No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Dynamic Optical Coherence Tomography in Dermatology
Abstract
Optical coherence tomography (OCT) represents a non-invasive imaging technology, which may be applied to the diagnosis of non-melanoma skin cancer and which has recently been shown to improve the diagnostic accuracy of basal cell carcinoma. Technical developments of OCT continue to expand the applicability of OCT for different neoplastic and inflammatory skin diseases. Of these, dynamic OCT (D-OCT) based on speckle variance OCT is of special interest as it allows the in vivo evaluation of blood vessels and their distribution within specific lesions, providing additional functional information and consequently greater density of data. In an effort to assess the potential of D-OCT for future scientific and clinical studies, we have therefore reviewed the literature and preliminary unpublished data on the visualization of the microvasculature using D-OCT. Information on D-OCT in skin cancers including melanoma, as well as in a variety of other skin diseases, is presented in an atlas. Possible diagnostic features are suggested, although these require additional validation.
... To address these limitations, recent advancements in non-invasive imaging have been fundamental. In particular, dynamic optical coherence tomography (D-OCT) excels in its ability to provide high-resolution three-dimensional images of the skin´s microvascular network to depths of up to 500 μm using near-infrared light [7,8]. This technology not only improves detection and diagnosis of AK but also deepens our insights into vascular involvement in disease development [8]. ...
... In particular, dynamic optical coherence tomography (D-OCT) excels in its ability to provide high-resolution three-dimensional images of the skin´s microvascular network to depths of up to 500 μm using near-infrared light [7,8]. This technology not only improves detection and diagnosis of AK but also deepens our insights into vascular involvement in disease development [8]. Until now, D-OCT research has focused on qualitative analysis of vessel morphologies, a method prone to inter-observer variability. ...
... Although a few published reports have quantitatively assessed vascular features in AK, they have typically focused on single parameters [15, 17]. These previous studies have described the presence of a reticular vascular network in AK with vessels of slightly larger diameter, and more superficially located than in healthy skin [7,8,15]. In contrast, our study´s more detailed approach using multiple quantitative parameters yielded more comprehensive insights into AK´s vascular network. ...
Clinical grading of actinic keratosis (AK) is based on skin surface features, while subclinical alterations are not taken into consideration. Dynamic optical coherence tomography (D-OCT) enables quantification of the skin´s vasculature, potentially helpful to improve the link between clinical and subclinical features. We aimed to compare microvascular characteristics across AK grades using D-OCT with automated vascular analysis. This explorative study examined AK and photodamaged skin (PD) on the face or scalp. AKs were clinically graded according to the Olsen Classification scheme before D-OCT assessment. Using an open-source software tool, the OCT angiographic analyzer (OCTAVA), we quantified vascular network features, including total and mean vessel length, mean vessel diameter, vessel area density (VAD), branchpoint density (BD), and mean tortuosity from enface maximum intensity projection images. Additionally, we performed subregional analyses on selected scans to overcome challenges associated with imaging through hyperkeratosis (each lesion group; n = 18). Our study included 45 patients with a total of 205 AKs; 93 grade I lesions, 65 grade II, 47 grade III and 89 areas with PD skin. We found that all AK grades were more extensively vascularized relative to PD, as shown by greater total vessel length and VAD (p ≤ 0.009). Moreover, AKs displayed a disorganized vascular network, with higher BD in AK I-II (p < 0.001), and mean tortuosity in AK II-III (p ≤ 0.001) than in PD. Vascularization also increased with AK grade, showing significantly greater total vessel length in AK III than AK I (p = 0.029). Microvascular quantification of AK unveiled subclinical, quantitative differences among AK grades I-III and PD skin. D-OCT-based microvascular assessment may serve as a supplement to clinical AK grading, potentially raising perspectives to improve management strategies.
... 2,3,5 Previous studies have reported that noninvasive imaging techniques such as optical coherence tomography (OCT), in vivo reflectance confocal microscopy (RCM) and line-field confocal optical coherence tomgoraphy show greater sensitivity and specificity than dermoscopy alone and may allow earlier diagnosis of NMSC. [6][7][8][9][10][11][12][13][14][15][16][17] OCT visualizes the skin up to a depth of at least 1 mm in cross-sectional and horizontal images, [18][19][20] while RCM visualizes the skin up to a depth of 250 μm at the cellular level in horizontal images 6,7,21 ; both devices use a low-power laser beam with emission of near-infra-red light into the tissue. 6,7,[18][19][20][21] In the present study, the authors examined the diagnostic performance of OCT and RCM in comparison with dermoscopy and also evaluated whether the combination of OCT and RCM can yield better diagnostic performance than that achieved with each method alone. ...
... [6][7][8][9][10][11][12][13][14][15][16][17] OCT visualizes the skin up to a depth of at least 1 mm in cross-sectional and horizontal images, [18][19][20] while RCM visualizes the skin up to a depth of 250 μm at the cellular level in horizontal images 6,7,21 ; both devices use a low-power laser beam with emission of near-infra-red light into the tissue. 6,7,[18][19][20][21] In the present study, the authors examined the diagnostic performance of OCT and RCM in comparison with dermoscopy and also evaluated whether the combination of OCT and RCM can yield better diagnostic performance than that achieved with each method alone. Furthermore, they examined if the addition of OCT and RCM can lead to improved management of suspicious lesions. ...
... 19,20 OCT generates a horizontal and an en-face image and can visualize the epidermis and dermis up to at least 1 mm depth. 18,19 OCT can therefore differentiate between different types of NMSC and its precursors and between different subtypes of BCC by showing the form of the tumour nests. [27][28][29][30][31] The use of dynamic OCT can aid in the diagnosis of melanocytic lesions and inflammatory diseases by visualization of the vessels, however due to the lower resolution, no cells are visible and therefore the benefit of OCT for these diagnoses is limited. ...
Background
Optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) can yield improved diagnostic accuracy of nonmelanoma skin cancer (NMSC) in comparison with dermoscopy alone.
Objectives
The aim of this study was to compare the diagnostic performance of OCT and RCM together and individually with that of dermoscopy.
Methods
Patients with lesions suspicious for NMSC were randomized into two groups in a prospective, single‐centre study. In the intervention group (IG), every lesion was examined with dermoscopy, OCT and RCM, while in the control group (CG), every lesion was examined with dermoscopy alone.
Results
A total of 365 lesions of 250 patients (105 female, 145 male) were included in the study. A total of 208 basal cell carcinomas (BCCs), 65 squamous cell carcinomas (SCCs) and 31 SCCs in situ were examined histologically. The IG involved significantly fewer biopsies than the CG (14 vs. 27, p = 0.029) and required fewer additional inpatient stays due to positive biopsy results (2 vs. 12, p = 0.001). For the diagnosis of BCC, diagnostic accuracy was 81% with dermoscopy, 84% with OCT, 83% with RCM and 85% with the combination of OCT and RCM (OCT/RCM). The diagnostic accuracy of OCT for BCC subtypes was as follows: superficial, 89%; nodular, 79%; sclerodermiform, 82%; and nodular‐cystic BCC, 75%. For the diagnosis of SCC, diagnostic accuracy was 85% with dermoscopy, 87% with OCT, 89% with RCM and 87% with OCT/RCM. For the diagnosis of in situ SCC, diagnostic accuracy was 87% with dermoscopy, 89% with OCT, 89% with RCM and 91% with OCT/RCM.
Conclusions
Diagnostic accuracy increased with OCT and RCM and was even higher when both methods were used together. OCT and RCM could facilitate optimization of lesion management by reducing the number of punch biopsies and reducing additional inpatient stays due to positive biopsy results.
... Hence ovoid, nests may be variable in reflectivity. Ovoid dermal structures with varying reflectivity are also a criterion for diagnosing SCC on OCT.16 Differentiating tumor nests of SCC and BCC on conventional OCT, therefore, remains challenging.16 Various studies have proposed that dynamic OCT (D-OCT), which visualizes vessel morphology based on speckle variance may be more suitable than conventional OCT for detecting SCC. ...
... Hence ovoid, nests may be variable in reflectivity. Ovoid dermal structures with varying reflectivity are also a criterion for diagnosing SCC on OCT.16 Differentiating tumor nests of SCC and BCC on conventional OCT, therefore, remains challenging.16 Various studies have proposed that dynamic OCT (D-OCT), which visualizes vessel morphology based on speckle variance may be more suitable than conventional OCT for detecting SCC. ...
... Various studies have proposed that dynamic OCT (D-OCT), which visualizes vessel morphology based on speckle variance may be more suitable than conventional OCT for detecting SCC. 16,17 D-OCT may visualize a diversified pattern of irregularly shaped and arranged vessels in SCC as opposed to centered and tumor island infiltrating vessels in BCC.16 Hence the addition of D-OCT to conventional OCT may be beneficial for differentiating between BCC and SCC in cases wherein ovoid dermal structures with varying reflectivity are present. coherence tomography only provides information on the gross architecture of the skin. ...
Optical coherence tomography (OCT), a non‐invasive diagnostic modality, may replace biopsy for diagnosing basal cell carcinoma (BCC) if a high‐confidence BCC diagnosis can be established. In other cases, biopsy remains necessary to establish a histopathological diagnosis and treatment regimen. It is, therefore, essential that OCT assessors have a high specificity for differentiating BCC from non‐BCC lesions. To establish high‐confidence BCC diagnoses, specific morphological BCC characteristics on OCT are used. This study aimed to review several cases of non‐BCC lesions that were misclassified as BCC by experienced OCT assessors, thereby providing insight into the causes of these misclassifications and how they may be prevented. The study population consisted of patients who had a histopathologically‐verified non‐BCC lesion. Patients from Maastricht University Medical Center+ from February 2021 to April 2021 were included in the study. Two independent OCT assessors assessed OCT scans. One OCT assessor recorded the presence or absence of validated morphological BCC characteristics. A false‐positive OCT test result was defined as certainty of BCC presence in a non‐BCC lesion. The frequency of misclassifications and the presence or absence of morphological BCC features are discussed. A total of 124 patients with non‐BCC lesions were included. Six patients were misclassified by both OCT assessors and are discussed in more detail. Histopathological diagnoses were squamous cell carcinoma ( n = 2/21), actinic keratosis ( n = 2/29), squamous cell carcinoma in situ/Bowen's disease ( n = 1/16), or interphase dermatitis ( n = 1/4). In all misclassified cases, multiple, apparent morphological BCC characteristics on OCT were present. Most non‐BCC lesions are recognized as such by OCT assessors. However, there remains a small risk that a high‐confidence BCC diagnosis is established in non‐BCC lesions wherein features mimicking validated BCC characteristics are present. Misclassification may be prevented by careful delineation of epidermal layers and good differentiation between dermal ovoid structures typical of BCC versus squamous cell carcinoma.
... Dynamic optical coherence tomography (D-OCT) stands as an established imaging method in the diagnosis of BCC, providing tumoral delimitation and an exact analysis of the vascular plexus. [7][8][9] The possible application of this technique in targeting and monitoring laser therapy of BCC is yet to be examined. ...
... This technique provided an enface field of view of 6 mm × 6 mm. OCT was used for the diagnosis of BCC, as previously described by Ulrich,7 and for evaluating tumour thickness and lateral extent. In addition, D-OCT was utilised to systematically evaluate the tumour-associated vascular plexus, providing estimates of the depth of the plexus and the density of blood vessels in tumour sites. ...
Background
Basal cell carcinomas (BCC) have classically been surgically removed. Alternative treatments for superficial BCC include local immunotherapy, topical chemotherapy and photodynamic therapy. Recent data suggest 1064 nm Nd:YAG laser as a new treatment for those lesions.
Dynamic optical coherence tomography (D‐OCT) is an established imaging procedure analysing BCC margins and its vascular plexus.
Objective
Our goal is to further evaluate 1064 nm Nd:YAG laser therapy of BCC as a potential alternative treatment, employing D‐OCT and histopathology to standardise effective treatment protocols.
Methods
In this retrospective cohort study, 50 histologically confirmed superficial and nodular BCC with tumour thickness ≤1 mm were treated with 1064 nm Nd:YAG laser. Initial D‐OCT scans were performed and repeated for 3 months posttreatment. Tumoral clearance was histologically confirmed and local adverse effects, patient tolerability and satisfaction were recorded. Clinical remission was evaluated after 1 year.
Results
Complete clearance was achieved in 78% of BCC (39/50) at a 3‐month follow‐up. Treatment failures were slightly more likely to correspond to superficial BCC (91%, 10/11) of thickness ≤0.5 mm (73%, 8/11), located on the trunk (64%, 7/11). No treated lesions presented scarring. Patient satisfaction and tolerability displayed excellent results. Remission at 1 year occurred in 100% of initially cleared BCC (35/35, four patients were lost to follow‐up due to nonmedical reasons).
Conclusion
OCT‐assisted 1064 nm Nd:YAG laser treatment of superficial BCC is a safe and effective method with excellent patient satisfaction, tolerability, practicability and cosmetic end result.
... With broadband infrared lasers (e.g., 1300 ± 100 nm), the OCT can provide theoretically 2-10 µm axial resolution tomographic structural images with depth information up to 2-3 mm in biological tissue [2]. In the past two decades, OCT has developed well in ophthalmology [3], dermatology [4] and intravascular imaging [5]. In the application of skin disease diagnosis and monitoring, OCT structural imaging has been used in non-melanoma skin cancer [6], basal cell carcinomas [7] and actinic keratosis [8]. ...
... I max is the maximum value in the images. MSE is the mean square error in (4). ...
Traditional high-quality OCTA images require multi-repeated scans (e.g., 4-8 repeats) in the same position, which may cause the patient to be uncomfortable. We propose a deep-learning-based pipeline that can extract high-quality OCTA images from only two-repeat OCT scans. The performance of the proposed image reconstruction U-Net (IRU-Net) outperforms the state-of-the-art UNet vision transformer and UNet in OCTA image reconstruction from a two-repeat OCT signal. The results demonstrated a mean peak-signal-to-noise ratio increased from 15.7 to 24.2; the mean structural similarity index measure improved from 0.28 to 0.59, while the OCT data acquisition time was reduced from 21 seconds to 3.5 seconds (reduced by 83%).
... Optical coherence tomography angiography (OCT-A) is method to directly visualize capillary-level vascular and structural features within skin in vivo, which has the potential to provide new insights into the pathophysiology, as well as dynamic changes of SSc skin [48]. OCT-A visualizes vasculatures from two separate layers of skin, the small capillaries of the superficial papillary dermis and the larger vessels of the deeper reticular dermis [49]. ...
... OCT-A imaging of the nailfold correlates with microvascular injury classically described by NVC [49]. The development of dynamic OCT is proposed a standardized imaging technique that could potentially provide a quantitative outcome measure in clinical trials and practice [50■■]. ...
Purpose of review:
Vascular assessment in systemic sclerosis (SSc) is included in classification criteria for this disease, thus routinely used in the evaluation of patients in which this diagnosis is being considered. In this review, imaging techniques for assessment of vascular involvement in SSc hands and skin are discussed.
Recent findings:
Longitudinal use of imaging techniques has important implications for understanding the progressive vasculopathy and fibrotic transition in SSc. Nailfold and oral capillaroscopy as well as laser speckle contrast analysis are established techniques for vascular functional assessment, but longitudinal use is challenged by equipment costs and clinical time constraints. Ultrasound techniques are well described but require technical training. Advances in mobile infrared thermography and optical coherence tomography could potentially provide a point-of-care, quantitative outcome measure in clinical trials and practice.
Summary:
The equipment cost, technical training, data standardization, and invasiveness of vascular assessment techniques that quantify morphological (microangiopathy) and functional (blood flow reduction) are critical for implementation into SSc clinical trials and practice to understand progressive vasculopathy, such as wound development.
... Discrete, regularly spaced dots can be observed on D-OCT in pigmented nevi, indicating the presence of vascularity. Nevertheless, in the context of melanoma, it is commonly observed that these vessels exhibit a more compact and disordered arrangement, characterized by irregular cylindrical forms when viewed in the vertical plane [46]. Recent research has demonstrated that Doppler optical coherence tomography (D-OCT) has the potential to contribute to the prognostication of patients with melanoma. ...
The prevalence of melanoma of the skin has seen a significant rise in recent decades, constituting approximately one-third of all diagnosed cancer cases. Melanoma, the most fatal variant among cutaneous malignancies, exhibits a 4% probability of occurrence over an individual’s lifetime. The increasing incidence and mortality rates of skin cancer impose a substantial burden on healthcare resources and the economy. In recent years, several optical modalities, including dermoscopy, reflectance confocal microscopy (RCM), optical coherence tomography, multiphoton excited fluorescence imaging, and dermatofluorescence, have been extensively studied and utilized to improve the non-invasive diagnosis of skin cancer. This review article provides an analysis of the approach employed in the recently developed optical non-invasive diagnostic technologies. It explores the clinical uses of these techniques, while also examining their respective advantages and disadvantages. Furthermore, the paper explores the possibility for additional advancements in these technologies in the future.
... 96 It has also been shown to have potential for monitoring therapy for skin disorders such as scleroderma, psoriasis, eczema, and wound healing. [96][97][98] The skin layers from the stratum corneum to the upper dermis, and skin appendages and blood vessels can be clearly imaged. 95 Although OCT has been shown to accurately image the development of actinic keratosis (AK), a precursor to squamous cell carcinoma (SCC), in patients of FST I-III, the majority of studies do not mention skin color and this is likely due to the perception that AK only affects people with light skin. ...
Significance
Skin color affects light penetration leading to differences in its absorption and scattering properties. COVID-19 highlighted the importance of understanding of the interaction of light with different skin types, e.g., pulse oximetry (PO) unreliably determined oxygen saturation levels in people from Black and ethnic minority backgrounds. Furthermore, with increased use of other medical wearables using light to provide disease information and photodynamic therapies to treat skin cancers, a thorough understanding of the effect skin color has on light is important for reducing healthcare disparities.
Aim
The aim of this work is to perform a thorough review on the effect of skin color on optical properties and the implication of variation on optical medical technologies.
Approach
Published in vivo optical coefficients associated with different skin colors were collated and their effects on optical penetration depth and transport mean free path (TMFP) assessed.
Results
Variation among reported values is significant. We show that absorption coefficients for dark skin are ∼6% to 74% greater than for light skin in the 400 to 1000 nm spectrum. Beyond 600 nm, the TMFP for light skin is greater than for dark skin. Maximum transmission for all skin types was beyond 940 nm in this spectrum. There are significant losses of light with increasing skin depth; in this spectrum, depending upon Fitzpatrick skin type (FST), on average 14% to 18% of light is lost by a depth of 0.1 mm compared with 90% to 97% of the remaining light being lost by a depth of 1.93 mm.
Conclusions
Current published data suggest that at wavelengths beyond 940 nm light transmission is greatest for all FSTs. Data beyond 1000 nm are minimal and further study is required. It is possible that the amount of light transmitted through skin for all skin colors will converge with increasing wavelength enabling optical medical technologies to become independent of skin color.
... Confocal microscopy requires high optical energy per volume element and only reaches a few tens of microns deep [18]. Optical coherence tomography (OCT) [19,20] and raster-scan optoacoustic mesoscopy (RSOM) reach deeper into the skin and can also extract vascular features. However, the optoacoustic method has deeper penetration and provides stronger contrast from the vasculature, holding the potential to become a widespread method for the study of skin morphology and function. ...
Ultra-wideband raster-scan optoacoustic mesoscopy (RSOM) is a novel modality that has demonstrated unprecedented ability to visualize epidermal and dermal structures
in-vivo
. However, an automatic and quantitative analysis of three-dimensional RSOM datasets remains unexplored. In this work we present our framework: Deep Learning RSOM Analysis Pipeline (DeepRAP), to analyze and quantify morphological skin features recorded by RSOM and extract imaging biomarkers for disease characterization. DeepRAP uses a multi-network segmentation strategy based on convolutional neural networks with transfer learning. This strategy enabled the automatic recognition of skin layers and subsequent segmentation of dermal microvasculature with an accuracy equivalent to human assessment. DeepRAP was validated against manual segmentation on 25 psoriasis patients under treatment and our biomarker extraction was shown to characterize disease severity and progression well with a strong correlation to physician evaluation and histology. In a unique validation experiment, we applied DeepRAP in a time series sequence of occlusion-induced hyperemia from 10 healthy volunteers. We observe how the biomarkers decrease and recover during the occlusion and release process, demonstrating accurate performance and reproducibility of DeepRAP. Furthermore, we analyzed a cohort of 75 volunteers and defined a relationship between aging and microvascular features
in-vivo
. More precisely, this study revealed that fine microvascular features in the dermal layer have the strongest correlation to age. The ability of our newly developed framework to enable the rapid study of human skin morphology and microvasculature in-vivo promises to replace biopsy studies, increasing the translational potential of RSOM.
... In BCC patients, OCT images showed a disorganised vascular plexus with tortuous vessels (Fig. 2C and SI Appendix, Fig. S6A), as previously published (35,36). Quantification revealed a signif icant increase in blood vessel density in the tumour compared to adjacent skin from the same patient (Fig. 2D). ...
Our understanding of how human skin cells differ according to anatomical site and tumour formation is limited. To address this, we have created a multiscale spatial atlas of healthy skin and basal cell carcinoma (BCC), incorporating in vivo optical coherence tomography, single-cell RNA sequencing, spatial global transcriptional profiling, and in situ sequencing. Computational spatial deconvolution and projection revealed the localisation of distinct cell populations to specific tissue contexts. Although cell populations were conserved between healthy anatomical sites and in BCC, mesenchymal cell populations including fibroblasts and pericytes retained signatures of developmental origin. Spatial profiling and in silico lineage tracing support a hair follicle origin for BCC and demonstrate that cancer-associated fibroblasts are an expansion of a POSTN + subpopulation associated with hair follicles in healthy skin. RGS5+ pericytes are also expanded in BCC suggesting a role in vascular remodelling. We propose that the identity of mesenchymal cell populations is regulated by signals emanating from adjacent structures and that these signals are repurposed to promote the expansion of skin cancer stroma. The resource we have created is publicly available in an interactive format for the research community.
... Optical coherence tomography (OCT) noninvasively provides micron-scale cross-sectional and 3D images of biological tissues in a wide variety of clinical applications, including ophthalmology 6,7 , cardiology 8-10 , endoscopy [11][12][13] , dermatology [14][15][16] , and dentistry [17][18][19] . OCM 20 , which integrates OCT and confocal detection, offers high resolution at an image penetration depth of around 500 µm, deep enough to image the larval, pupal, and adult Drosophila heart. ...
The heart of the fruit fly, Drosophila melanogaster , is a particularly suitable model for cardiac studies. Optical coherence microscopy (OCM) captures in vivo cross-sectional videos of the beating Drosophila heart for cardiac function quantification. To analyze those large-size multi-frame OCM recordings, human labelling has been employed, leading to low efficiency and poor reproducibility. Here, we introduce a robust and accurate automated Drosophila heart segmentation algorithm, called FlyNet 2.0+, which utilizes a long short-term memory (LSTM) convolutional neural network to leverage time series information in the videos, ensuring consistent, high-quality segmentation. We present a dataset of 213 Drosophila heart videos, equivalent to 604,000 cross-sectional images, containing all developmental stages and a wide range of beating patterns, including faster and slower than normal beating, arrhythmic beating, and periods of heart stop to capture these heart dynamics. Each video contains a corresponding ground truth mask. We expect this unique large dataset of the beating Drosophila heart in vivo will enable new deep learning approaches to efficiently characterize heart function to advance cardiac research.
... 1,2 Optical coherence tomography (OCT) is a noninvasive imaging device that visualizes the skin up to a depth of 1.5 mm and the morphology of vessels with dynamic OCT (DOCT). 3,4 Linefield confocal OCT (LC-OCT) is a combination of OCT and confocal microscopy (CM) 5 that enables threedimensional imaging of the skin up to a depth of 0.5 mm at the cellular level. 5 In this prospective case study, we examined CM with dermoscopy as established by Costa et al., 1,6 OCT and LC-OCT to describe common findings. ...
Background
Cutaneous metastases (CM) are a frequent finding in the follow‐up of malignant tumours.
Objectives
CM were examined with dermoscopy, optical coherence tomography (OCT), dynamic OCT and line‐field confocal OCT (LC‐OCT) to describe common findings.
Methods
In the University Hospital Carl Gustav Carus Dresden, Germany, 18 patients with 61 CM were examined with dermoscopy. CM (n = 43, 31 melanoma metastases, two metastases of renal carcinoma, five metastases of cutaneous squamous cell carcinoma and five metastases of pleomorphic dermal sarcoma) were examined with OCT (VivoSight® Michelson Diagnostics). Additional 18 melanoma metastases were examined with LC‐OCT (deepLive™; Damae Medical).
Results
CM were localized on the head, trunk, neck and limbs. Dermoscopy patterns were angioma‐like, nevus‐like nonglobular, nevus‐like globular, blue nevus‐like and unspecific. CM showed an ulceration, hyperkeratosis with increased entrance signal and disturbed architecture of the epidermis in OCT. In deeper metastases, the dermoepidermal junction (DEJ) was normal; in most cases it was disturbed. CM were visible as subepidermal hyporeflective roundish area, with septae, with either clear margin and shadowing or blurred margin. DOCT showed dot, coiled, serpiginous and branched vessels; there was a disarray in size and distribution and vessels were converging on the centre of the metastasis. In LC‐OCT, CM showed enhanced entrance signal and disturbed architecture of a thinned epidermis, ulceration, atypical honeycomb or cobblestone pattern as well as a broken DEJ. In the dermis, a hyporeflective roundish area with clusters of hyporeflective cells with septae, clear margin and clefting or blurred margin was visible; the hyporeflective area was surrounded by bundles of connective tissue. Subepidermal vessels differentiated in size and distribution. Inflammatory, dendritic and pagetoid cells were visible.
Conclusions
OCT and LC‐OCT may be useful tools for immediate diagnosis, localization of CM and monitoring under treatment in addition to conventional methods like ultrasound and histopathology.
... Adjacent tissue thermal damage can be minimized with adequate laser pulse duration, which does not exceed the target chromophore unit's thermal relaxation time 22 that depends on the size of the chromophore unit: less than 1 μs for isolated melanosomal cells of 7-μm size and 10 ms for cluster sizes of about 100 μm 24 . Vascularization increases by two folds according to optical coherence tomographic data in the CMN lesion 25 , promoting the use of 578-nm yellow CVL radiation to prevent recurrence by heating dysplastic vessels 26,27 . ...
Purpose
Palpebral congenital melanocytic nevi (PCMN) is a rare congenital skin lesion affecting the eyelids that can lead to cosmetic and psychological concerns and potential health risks such as malignancy. Several authors have analyzed therapeutical strategies to treat PCMN. However, there was no consensus in the literature. This systematic review aimed to evaluate the effectiveness, safety, and success of treatments of PCMN.
Methods
We conducted a systematic review following PRISMA guidelines from October 2022 to April 2023. We included all types of study designs that described or compared PCMN treatments and interventions, as well as histology, recurrence, adverse events, patient satisfaction, and malignant transformation. The search strategy was based on specific search words through the following databases: PubMed, Embase, Latin American and Caribbean Health Sciences Literature (Lilacs), Web of Science, and Scopus. Ongoing studies and gray literature studies were included.
Results
We analyzed 25 case reports with 148 participants. The effectiveness, success, and satisfaction with various treatments for PCMN depend on the specific treatment method and the individual patient’s case.
Conclusions
Most of the studies showed that surgical procedures (exeresis) are able to treat PCMN in the eyelid. The variability in outcomes emphasizes the importance of further research to better understand the most effective and safe approaches for treating congenital melanocytic nevi.
Key words
Nevus, Pigmented; Eyelid Neoplasms
... Optical coherence tomography data indicate up to two times increased vascularization in the area of CMN. 16 The induction of melanogenesis by endothelial cells indicates the advisability of remodeling of the vascular bed associated with hyperpigmentation to prevent CMN relapsing. 17 Yellow CVL radiation at 578 nm can be applied for selective heating of the dysplastic vessels in the CMN area, 18,19 which demonstrates increased vascularization. ...
Introduction: Congenital melanocytic nevus (CMN) is a severe challenge for dermatology. This pigmented skin lesion is undesirable for patients because of its localization in open areas of the body. Various visible and near-infrared laser systems and intense pulsed light (IPL) sources have been applied for CMN treatment. However, post-traumatic hyperpigmentation, structural changes, atrophy, and scarring due to non-specific thermal damage have been observed. Many patients have shown recurrence after treatment. Therefore, it highlights the need for testing new laser modalities for the management of CMN.
Methods: Two adult II Fitzpatrick phototype patients (a 55-year-old male and a 30-year-old female) with middle-sized facial CMN (on the forehead and lower eyelid) are presented. All patients were treated with dual-wavelength copper vapor laser (CVL) radiation at 511 nm and 578 nm wavelengths with a power ratio of 3:2. The average power was 0.7-0.85 W with an exposure time of 0.3 seconds. The spot size amounted to 1 mm.
Results: Both patients showed complete resolution of CMN after CVL treatments. CMN became crusted within a few days after the laser treatment and peeled off within seven days. No recurrences were observed during the follow-up period up to 24 months.
Conclusion: The middle-sized CMN can be successfully treated with dual-wavelength CVL radiation.
... The physical principle of operation of OCT is similar to ultrasound, with the only difference being that OCT uses optical radiation in the near infrared range (~1 µm) rather than acoustic waves to probe biological tissue. In dermatology, OCT can be used for investigations of skin cancer, inflammatory diseases and wound healing and applied as an assistance for planning and controlling various treatments, such as follicular unit extraction and drug delivery through nails and skin [31,32]. ...
The formation of a dense fibrous capsule around the foreign body and its contracture is the most common complication of biomaterial implantation. The aim of our research is to find out how the surface of the implant influences the inflammatory and fibrotic reactions in the surrounding tissues. We made three types of implants with a remote surface topography formed of polylactide granules with different diameters: large (100–200 µm), medium (56–100 µm) and small (1–56 µm). We placed these implants in skin pockets in the ears of six chinchilla rabbits. We explanted the implants on the 7th, 14th, 30th and 60th days and performed optical coherence tomography, and histological, immunohistochemical and morphometric studies. We examined 72 samples and compared the composition of immune cell infiltration, vascularization, the thickness of the peri-implant tissues, the severity of fibrotic processes and α-SMA expression in myofibroblasts. We analyzed the scattering coefficient of tissue layers on OCT scans. We found that implants made from large granules induced a milder inflammatory process and slower formation of a connective tissue capsule around the foreign body. Our results prove the importance of assessing the surface texture in order to avoid the formation of capsular contracture after implantation.
... For a microvascular evaluation of the vessels in each melanoma scan, the OCT-Fitter V2.1 (created by Marco Manfredi and Constantino Grana, Modena) was used at three standardized depths: 150, 300 and 500 µm [10]. For a standardized assessment, the previously described terminology by Ulrich et al. was applied on the D-OCT images [8,11]. At the three depths, the vessel density, diameter, distribution, orientation, pattern, branching and direction were analyzed. ...
Dermoscopy adds important information to the assessment of cutaneous melanoma, but the risk of progression is predicted by histologic parameters and therefore requires surgery and histopathologic preparation. Neo-vascularization is crucial for tumor progression and worsens prognosis. The aim of this study was the in vivo evaluation of blood vessel patterns in melanoma with dynamic optical coherence tomography (D-OCT) and the correlation with dermoscopic and histologic malignancy parameters for the risk assessment of melanoma. In D-OCT vessel patterns, shape, distribution and presence/type of branching of 49 melanomas were evaluated in vivo at three depths and correlated with the same patterns in dermoscopy and with histologic parameters after excision. In D-OCT, blood vessel density and atypical shapes (coils and serpiginous vessels) increased with higher tumor stage. The histologic parameters ulceration and Hmb45- and Ki67-positivity increased, whereas regression, inflammation and PD-L1-positivity decreased with risk. CD31, VEGF and Podoplanin correlated with D-OCT vasculature findings. B-RAF mutation status had no influence. Due to pigment overlay and the summation effect, the vessel evaluation in dermoscopy and D-OCT did not correlate well. In summary, atypical vessel patterns in melanoma correlate with histologic parameters for risk for metastases. Tumor vasculature can be noninvasively assessed using D-OCT before surgery.
... Optical coherence tomography angiography (OCTA) is an evolving optical imaging technique that facilitates the in vivo visualization of functional blood vessels by detecting OCT signal changes triggered by moving particles (such as red blood cells) [14][15][16]. With its non-invasive characteristics and highresolution capabilities [17,18], OCTA has swiftly found applications in scientific research and various clinical fields, including ophthalmology [19][20][21], dermatology [22,23], and stomatology [24][25][26][27]. Recently, OCTA's potential has been harnessed to visualize cerebral microcirculation in animal models [14,28,29]. ...
Purpose: This study aims to evaluate the capability of optical coherence tomography angiography (OCTA) for imaging the microvasculature within a critical bone defect, to longitudinally observe vascular alterations, and quantify the microvascular density and morphology in a model of a critical-sized defect.
Methods: An OCTA system was used to longitudinally monitor angiogenesis in four rat models presenting critical-sized defects with observations recorded on days 7, 14, and 28 post-defect creation. Simultaneously, angiogenesis in three additional rat models was evaluated through a conventional histological analysis involving hematoxylin and eosin staining.
Results: OCTA was successful in acquiring in vivo 3D vascular perfusion mapping within the critical-sized defect, and it allowed for quantitative analysis of the microvasculature’s density and morphology. The OCTA imagery of the blood microvasculature revealed a noticeable augmentation in the number and size of vessels, with more extensive vessel convergence observed on day 14 compared to both days 7 and 28. Complementing these observations, quantitative analysis demonstrated that the vessel area density (VAD) and maximum vascular diameter index (MVDI) were significantly larger on day 14 in comparison to measurements taken on days 7 and 28.
Conclusion: Leveraging its ability to capture high-resolution images, OCTA facilitated longitudinal monitoring of angiogenesis in models of critical-sized defects. Therefore, it potentially serves as a non-invasive experimental tool beneficial for bone regeneration research.
... In BCC patients, OCT images showed a disorganised vascular plexus with tortuous vessels ( Fig. 2C; SI Appendix, Fig. 6A), as previously published (34,35). Quantification revealed a significant increase in blood vessel density in the tumour compared to adjacent skin from the same patient (Fig. 2D). ...
Our understanding of how human skin cells differ according to anatomical site and tumour formation is limited. To address this we have created a multi-scale spatial atlas of healthy skin and basal cell carcinoma (BCC), incorporating in vivo optical coherence tomography, single cell RNA sequencing, spatial global transcriptional profiling and in situ sequencing. Computational spatial deconvolution and projection revealed the localisation of distinct cell populations to specific tissue contexts. Although cell populations were conserved between healthy anatomical sites and in BCC, mesenchymal cell populations including fibroblasts and pericytes retained signatures of developmental origin. Spatial profiling and in silico lineage tracing support a hair follicle origin for BCC and demonstrate that cancer-associated fibroblasts are an expansion of a POSTN + subpopulation associated with hair follicles in healthy skin. RGS5+ pericytes are also expanded in BCC suggesting a role in vascular remodelling. We propose that the identity of mesenchymal cell populations is regulated by signals emanating from adjacent structures and that these signals are repurposed to promote the expansion of skin cancer stroma. The resource we have created is publicly available in an interactive format for the research community.
Significance statement
Single cells RNA sequencing has revolutionised cell biology, enabling high resolution analysis of cell types and states within human tissues. Here, we report a comprehensive spatial atlas of adult human skin across different anatomical sites and basal cell carcinoma (BCC) - the most common form of skin cancer - encompassing in vivo optical coherence tomography, single cell RNA sequencing, global spatial transcriptomic profiling and in situ sequencing. In combination these modalities have allowed us to assemble a comprehensive nuclear-resolution atlas of cellular identity in health and disease.
... As a dermatology tool, OCTA can detect angiogenesis and various vascular patterns that may aid in the early detection of melanoma and basal cell carcinoma (BCC) [2,3]. In addition, OCTA can improve diagnostic accuracy by identifying changes in blood flow associated with inflammatory skin diseases [4]. ...
This study develops a handheld optical coherence tomography angiography (OCTA) system that uses a high-speed (200 kHz) swept laser with a dual-reference common-path configuration for stable and fast imaging. The common-path design automatically avoids polarization and dispersion mismatches by using one circulator as the primary system element, ensuring a cost-effective and compact design for handheld probe use. With its stable envelope (i.e., sub-µm shifts) and phase variation (corresponding to nm changes in axial displacement), the minimum detectable flow velocity is ∼ 0.08 mm/s in our experiment, which gives the common-path setup a high potential for application in a handheld OCTA system for clinical skin screening. In vivo skin structures and microvasculature networks on the dorsum of the hand and cheek of a healthy human are imaged successfully.
... It is a non-contact, non-invasive, imaging technique that perfectly combines high resolution and large imaging depth to achieve a biopsy-like role in histopathology [4]. Currently, OCT technology has been widely used in clinical diagnosis in medical fields, such as ophthalmology [5], dentistry [6] and dermatology [7], because of the advantages described above, but the use of this technology in fields such as GSM and other gynecological diseases is still rare. Therefore, it is necessary to develop the application of OCT technology in fields such as GSM. ...
Genitourinary syndrome of menopause (GSM) is a group of syndromes, including atrophy of the reproductive tract and urinary tract, and sexual dysfunction, caused by decreased levels of hormones, such as estrogen, in women during the transition to, or late stage of, menopause. GSM symptoms can gradually become severe with age and menopausal time, seriously affecting the safety, and physical and mental health, of patients. Optical coherence tomography (OCT) systems can obtain images similar to “optical slices” in a non-destructive manner. This paper presents a neural network, called RVM-GSM, to implement automatic classification tasks for different types of GSM-OCT images. The RVM-GSM module uses a convolutional neural network (CNN) and a vision transformer (ViT) to capture local and global features of the GSM-OCT images, respectively, and, then, fuses the two features in a multi-layer perception module to classify the image. In accordance with the practical needs of clinical work, lightweight post-processing is added to the final surface of the RVM-GSM module to compress the module. Experimental results showed that the accuracy rate of RVM-GSM in the GSM-OCT image classification task was 98.2%. This result is better than those of the CNN and Vit models, demonstrating the promise and potential of the application of RVM-GSM in the physical health and hygiene fields for women.
... OCT is a non-destructive, three-dimensional imaging technique with advantages such as cross-sectional, high-resolution, and real-time tissue imaging [17][18][19][20], and it is widely used in skin detection studies [6,[21][22][23][24]. In studies about skin diseases or damage, OCT is used in animal experiments. ...
Ultraviolet (UV) irradiation causes 90% of photodamage to skin and long-term exposure to UV irradiation is the largest threat to skin health. To study the mechanism of UV-induced photodamage and the repair of sunburnt skin, the key problem to solve is how to non-destructively and continuously evaluate UV-induced photodamage to skin. In this study, a method to quantitatively analyze the structural and tissue optical parameters of artificial skin (AS) using optical coherence tomography (OCT) was proposed as a way to non-destructively and continuously evaluate the effect of photodamage. AS surface roughness was achieved based on the characteristic peaks of the intensity signal of the OCT images, and this was the basis for quantifying AS cuticle thickness using Dijkstra’s algorithm. Local texture features within the AS were obtained through the gray-level co-occurrence matrix method. A modified depth-resolved algorithm was used to quantify the 3D scattering coefficient distribution within AS based on a single-scattering model. A multiparameter assessment of AS photodamage was carried out, and the results were compared with the MTT experiment results and H&E staining. The results of the UV photodamage experiments showed that the cuticle of the photodamaged model was thicker (56.5%) and had greater surface roughness (14.4%) compared with the normal cultured AS. The angular second moment was greater and the correlation was smaller, which was in agreement with the results of the H&E staining microscopy. The angular second moment and correlation showed a good linear relationship with the UV irradiation dose, illustrating the potential of OCT in measuring internal structural damage. The tissue scattering coefficient of AS correlated well with the MTT results, which can be used to quantify the damage to the bioactivity. The experimental results also demonstrate the anti-photodamage efficacy of the vitamin C factor. Quantitative analysis of structural and tissue optical parameters of AS by OCT enables the non-destructive and continuous detection of AS photodamage in multiple dimensions.
... Optical coherence tomography (OCT) is non-invasive optical imaging equipment developed based on the Michelson interferometer to visualize tomography information of tissues several millimeters deep below the surface [1]. Thanks to their real-time imaging capabilities and excellent axial and spatial resolution, optical interference tomography devices are used as major examination tools for ophthalmology, dermatology, oncology, and dentistry [2][3][4][5][6][7][8]. In addition to medical and biomedical applications, optical interference tomography devices are widely applied, including industrial and agricultural applications [9][10][11]. ...
... 17,18 In dermatology, the Dynamic-OCT has shown good ability to image different skin disease and its vascular component. [19][20][21] However, this is currently limited by relatively long scanning time and is yet to be commercially available. We propose a pilot study to evaluate whether commercially available OCTA designed for ophthalmological purpose can visualise the nailfold capillaries. ...
... Another imaging technique used in dermatology, optical coherence tomographic (OCT) imaging, is a specialized technique for 3D structural imaging that can better segment the skin layers. [68][69][70] Considering their advantages, PA and OCT imaging can be utilized in tandem to yield more accurate information. ...
Significance:
Corticosteroids-commonly prescribed medications for skin diseases-inhibit the secretion of vasodilators, such as prostaglandin, thereby exerting anti-inflammatory action by constricting capillaries in the dermis. The effectiveness of corticosteroids is determined by the degree of vasoconstriction followed by skin whitening, namely, the blanching effect. However, the current method of observing the blanching effect indirectly evaluates the effects of corticosteroids.
Aim:
In this study, we employed optical-resolution photoacoustic (PA) microscopy (OR-PAM) to directly visualize the blood vessels and quantitatively evaluate vasoconstriction.
Approach:
Using OR-PAM, the vascular density in mice skin was monitored for 60 min after performing each experimental procedure for four groups, and the vasoconstriction was quantified. Volumetric PA data were segmented into the papillary dermis, reticular dermis, and hypodermis based on the vascular characteristics obtained through OR-PAM. The vasoconstrictive effect of each skin layer was quantified according to the dermatological treatment method.
Results:
In the case of corticosteroid topical application, vasoconstriction was observed in the papillary ( 56.4 ± 10.9 % ) and reticular ( 45.1 ± 4.71 % ) dermis. For corticosteroid subcutaneous injection, constriction was observed solely in the reticular ( 49.5 ± 9.35 % ) dermis. In contrast, no vasoconstrictions were observed with nonsteroidal topical application.
Conclusions:
Our results indicate that OR-PAM can quantitatively monitor the vasoconstriction induced by corticosteroids, thereby validating OR-PAMs potential as a practical evaluation tool for predicting the effectiveness of corticosteroids in dermatology.
... 19,20 OCT employs a 1305-nm laser source that allows vertical optical step sections of ∼7 μm, with a lateral resolution of ∼10 μm and provides skin architectural information up to 1 mm depth within a FOV of 1 × 2 mm. 21,22 The handheld RCM and OCT devices were applied directly to the sampling areas just after the first tape strip(s) to avoid microorganism contamination [the first tape strip(s) were stored for future microbiome analysis] and after the final tape strip (Figure 2). At least one RCM vertical stack of horizontal images and at least one OCT raster of vertical images were acquired. ...
Background
Molecular skin profiling techniques, typically performed on skin samples taken by punch biopsy, have enhanced the understanding of the pathophysiology of atopic dermatitis (AD), thereby enabling the development of novel targeted therapeutics. However, punch biopsies are not always feasible or desirable, and novel minimally invasive methods such as skin tape stripping have been developed.
Aim
To develop, optimize and validate a novel tape stripping method guided by noninvasive in vivo skin imaging to sample atopic skin in children.
Methods
Skin tape stripping-based procedures were compared and optimized using data from 30 healthy controls (HCs: 5 adults, 25 children) and 39 atopic children. Evaluations were guided by high-resolution photography, reflectance confocal microscopy, optical coherence tomography and transepidermal water loss measurements. We assessed and compared adverse events (AEs), the time needed to perform the sampling and the cDNA levels obtained from the tapes.
Results
Tape stripping methods based on previously described protocols resulted in erosions in all participants and required a median time of 65 min to perform (range 60–70 min), but provided good cDNA yield. Shorter durations appeared less invasive but provided lower cDNA yield. The final optimized tape stripping protocol, using 11 tapes of 22 mm in diameter, each applied twice for 5 s with 90° rotation, did not produce significant AEs, was completed within a median time of 7 min (range 5–15 min) and provided good cDNA yield both in HCs and atopic children.
Conclusion
Our minimally invasive method is safe and reliable, and provides reproducible acquisition of cDNA in atopic children. In addition, it enables rapid sample collection, a crucial factor in clinical practice.
... The high-speed imaging of the OCT provides the surgeon with information on the proper placement of the stent, avoiding malapposition and large stent edge dissections [5,6]. The advent of SS-OCT greatly improves the quality of esophagus imaging and provides a great deal of help in predicting esophageal adenocarcinoma (EAC) [7,8]. OCT is also increasingly being used for imaging in vasculature [9][10][11]. ...
Optical Coherence Tomography (OCT) is widely used for endoscopic imaging in endoluminal organs because of its high imaging accuracy and resolution. However, OCT endoscopic imaging suffers from Non-Uniform Rotational Distortion (NURD), which can be caused by many factors, such as irregular motor rotation and changes in friction between the probe and the sheath. Correcting this distortion is essential to obtaining high-quality Optical Coherence Tomography Angiography (OCTA) images. There are two main approaches for correcting NURD: hardware-based methods and algorithm-based methods. Hardware-based methods can be costly, challenging to implement, and may not eliminate NURD. Algorithm-based methods, such as image registration, can be effective for correcting NURD but can also be prone to the problem of NURD propagation. To address this issue, we process frames by coarse and fine registration, respectively. The new reference frame is generated by filtering out the A-scan that may have the NURD problem by coarse registration. And the fine registration uses this frame to achieve the final NURD correction. In addition, we have improved the Features from Accelerated Segment Test (FAST) algorithm and put it into coarse and fine registration process. Four evaluation functions were used for the experimental results, including signal-to-noise ratio (SNR), peak signal-to-noise ratio (PSNR), mean squared error (MSE), and structural similarity index measure (SSIM). By comparing with Scale-invariant feature transform (SIFT), Speeded up robust features (SURF), Oriented FAST and Rotated BRIEF (ORB), intensity-based (Cross-correlation), and Optical Flow algorithms, our algorithm has a higher similarity between the corrected frames. Moreover, the noise in the OCTA data is better suppressed, and the vascular information is well preserved. Our image registration-based algorithm reduces the problem of NURD propagation between B-scan frames and improves the imaging quality of OCT endoscopic images.
... Still, neither conventional nor high-definition OCT [23,24] can visualize distinguishing features in melanocytic lesions [23,24]. D-OCT shows physiological blood flow changes [9], influences of topical treatments [39], and in vivo microvascularization in tumors, inflammatory, and degenerative dermatological conditions [22,40]. ...
Simple Summary
Nevi and melanomas are usually distinguished based on the current gold standard of a clinical-dermoscopic evaluation. Unclear cases, on the other hand, may require additional imaging. Optical coherence tomography (OCT) is a non-invasive imaging technique. It is routinely used for non-melanoma skin cancer but failed to recognize distinguishing features in melanocytic lesions. Dynamic OCT (D-OCT) visualizes microvascularization and has shown promise regarding non-melanoma skin cancer and melanomas. Currently, larger studies on nevi are lacking. Therefore, in this study, we described specific microvascular parameters in nevi and dysplastic nevi, compared them to melanomas, and evaluated D-OCT’s potential for differentiating melanocytic lesions. The addition to the clinical-dermoscopic examination may improve the diagnostic approach to unclear melanocytic lesions, limit unnecessary biopsies, and accelerate and individualize the treatment plan.
Abstract
Along with the rising melanoma incidence in recent decades and bad prognoses resulting from late diagnoses, distinguishing between benign and malignant melanocytic lesions has become essential. Unclear cases may require the aid of non-invasive imaging to reduce unnecessary biopsies. This multicentric, case-control study evaluated the potential of dynamic optical coherence tomography (D-OCT) to identify distinguishing microvascular features in nevi. A total of 167 nevi, including dysplastic ones, on 130 participants of all ages and sexes were examined by D-OCT and dermoscopy with a histological reference. Three blinded analyzers evaluated the lesions. Then, we compared the features to those in 159 melanomas of a prior D-OCT study and determined if a differential diagnosis was possible. We identified specific microvascular features in nevi and a differential diagnosis of melanomas and nevi was achieved with excellent predictive values. We conclude that D-OCT overcomes OCT´s inability to distinguish melanocytic lesions based on its focus on microvascularization. To determine if an addition to the gold standard of a clinical-dermoscopic examination improves the diagnosis of unclear lesions, further studies, including a larger sample of dysplastic nevi and artificial intelligence, should be conducted.
... Vascularity is seen on D-OCT in pigmented nevi as discrete, regularly spaced dots. However, in MM, these vessels typically show a denser and chaotic distribution, with irregular cylindrical shapes in the vertical section [66]. It has been found that D-OCT can aid in the prognosis of MM patients. ...
Skin cancer has shown a sharp increase in prevalence over the past few decades and currently accounts for one-third of all cancers diagnosed. The most lethal form of skin cancer is melanoma, which develops in 4% of individuals. The rising prevalence and increased number of fatalities of skin cancer put a significant burden on healthcare resources and the economy. However, early detection and treatment greatly improve survival rates for patients with skin cancer. Since the rising rates of both the incidence and mortality have been particularly noticeable with melanoma, significant resources have been allocated to research aimed at earlier diagnosis and a deeper knowledge of the disease. Dermoscopy, reflectance confocal microscopy, optical coherence tomography, multiphoton-excited fluorescence imaging, and dermatofluorescence are only a few of the optical modalities reviewed here that have been employed to enhance noninvasive diagnosis of skin cancer in recent years. This review article discusses the methodology behind newly emerging noninvasive optical diagnostic technologies, their clinical applications, and advantages and disadvantages of these techniques, as well as the potential for their further advancement in the future.
... [8,9] The use of noninvasive dermatoscopy (imaging of the skin, allowing statements concerning thickening of layers, epidermal organization, and borders of a lesion) or optical technologies, such as optical coherence tomography (noninvasive imaging test using light waves), may be helpful in improving diagnostic accuracy in some skin cancers. [10,11] Photodynamic visualization (fluorescent visualization of skin cancer extension after preparation with 5-aminolaevulinic acid and subject to photodynamic therapy [light exposure]) might also be beneficial for the identification of actinic keratosis, with histologic confirmation also being necessary in cases in which invasive skin cancer is suspected. [12] With both MM and NMSC, one confirms the diagnosis of a suspect lesion with skin biopsy and histopathological examination. ...
... Optical coherence tomography (OCT) is a fast, highresolution, in vivo imaging method with growing influence in the dermatological practice, especially in non-melanoma skin cancer (9)(10)(11)(12). The imaging technique of OCT is based on Michelson interferometry (13). ...
Biologic therapies are increasingly used to treat chronic inflammatory skin diseases such as psoriasis and atopic dermatitis. In clinical practice, scores based on evaluation of objective and subjective symptoms are used to assess disease severity, leading to evaluation of treatment goals with clinical decisions on treatment initiation, switch to another treatment modality or to discontinue current treatment. However, this visual-based scoring is relatively subjective and inaccurate due to inter- and intraobserver reliability. Optical coherence tomography (OCT) is a fast, high-resolution, in vivo imaging modality that enables the visualization of skin structure and vasculature. We evaluated the use of OCT for quantification and monitoring of skin inflammation to improve objective assessment of disease activity in patients with psoriasis and atopic dermatitis. We assessed the following imaging parameters including epidermal thickness, vascular density, plexus depth, vessel diameter, and vessel count. A total of four patients with psoriasis or atopic dermatitis were treated with biologic agents according to current treatment guidelines. OCT was used to monitor their individual treatment response in a target lesion representing disease activity for 52 weeks. Psoriatic and eczema lesions exhibited higher epidermal thickness, increased vascular density, and higher vessel count compared to uninvolved skin. An upward shift of the superficial vascular plexus accompanied by smaller vessel diameters was seen in psoriasis in contrast to atopic dermatitis, where larger vessels were observed. A response to biologic therapy was characterized by normalization of the imaging parameters in the target lesions in comparison to uninvolved skin during the observation period of 52 weeks. Optical coherence tomography potentially serves as an instrument to monitor biologic therapy in inflammatory skin diseases. Imaging parameters may enable objective quantification of inflammation in psoriasis or atopic dermatitis in selected representative skin areas. OCT may reveal persistent subclinical inflammation in atopic dermatitis beyond clinical remission.
... 3,4 This fundamental discordance is a gap that could be closed by the application of real-time histology evaluation by optical coherence tomography (OCT). OCT is a nondestructive, 3D microscopic imaging modality with cellular-level resolution 5 that is being applied currently in clinical ophthalmology 6 and dermatology 7 and is emerging in other specialties. 8,9 OCT provides a resolution and depth of field that is midway between traditional microscopy and clinical ultrasound. ...
Significance:
Real-time histology can close a variety of gaps in tissue diagnostics. Currently, gross pathology analysis of excised tissue is dependent upon visual inspection and palpation to identify regions of interest for histopathological processing. Such analysis is limited by the variable correlation between macroscopic and microscopic findings. The current standard of care is costly, burdensome, and inefficient.
Aim:
We are the first to address this gap by introducing optical coherence tomography (OCT) to be integrated in real-time during the pathology grossing process.
Approach:
This is achieved by our high-resolution, ultrahigh-speed, large field-of-view OCT device designed for this clinical application.
Results:
We demonstrate the feasibility of imaging tissue sections from multiple human organs (breast, prostate, lung, and pancreas) in a clinical gross pathology setting without interrupting standard workflows.
Conclusions:
OCT-based real-time histology evaluation holds promise for addressing a gap that has been present for >100 years.
... Previous descriptions with OCT and high-definition OCT in melanocytic lesions have had limited clinical applicability in the study of melanocytic lesions, owing to their insufficient resolution, which reduced their diagnostic sensitivity for detecting skin lesions such as melanoma. 39 Recently, dynamic OCT has been used to describe different patterns of vascularization in melanocytic tumours, which could be useful in evaluation of these lesions. 40 Moreover, Schuh et al. found that LC-OCT can be used to differentiate between naevi and melanoma, with 93% sensitivity and 100% specificity compared with RCM in diagnosing melanoma. ...
Background:
Line-field confocal optical coherence tomography (LC-OCT) is a new in vivo emerging technique which provides cellular resolution, imaging depth (400 μm) and produces real-time images in both the horizontal and vertical plane and in 3 dimensions (3D). No previous description of different subtypes of melanocytic lesions and their correlation with histopathology and reflectance confocal microscopy has been reported.
Objectives:
We aimed to describe the features of melanocytic lesions by LC-OCT and their correlation with histopathology and reflectance confocal microscopy (RCM).
Methods:
Selected melanocytic benign lesions and melanomas were imaged in vivo with RCM and LC-OCT at the Hospital Clinic of Barcelona. A minimum area of 4mm x 4mm (block image) at 4 depths (stratum granulosum, suprabasal, dermoepidermal-junction and upper dermis) were acquired with RCM and a minimum of 3 cubes with LC-OCT. Horizontal, vertical sections and 3D cubes of LC-OCT were matched with RCM Vivablock and histopathology with ~5 μm lateral resolution accuracy (the same cell nuclei were measured in X, Y and Z), and evaluated by three observers experienced in RCM and histopathology.
Results:
Twelve melanocytic tumors (2 in situ melanomas, 2 invasive melanomas, 4 atypical nevi, 2 intradermal nevi, one compound nevus and one junctional nevus) were included. A high correlation with 5 μm accuracy between RCM and LC-OCT was observed with each tumor. 3D images of melanocytic lesions were obtained with cellular resolution and correlated with both RCM and histopathology, allowing an understanding of the architecture and precise correlation at the cellular level with RCM. Similarities between LC-OCT and RCM for the described diagnostic features and in the architecture (nests of melanocytic cells, ringed and meshwork pattern, and cellular details of tumor cells as dendritic and pagetoid cells) were confirmed. The main advantage of diagnosis by RCM fixed probe was the capability to produce larger scans of the lesion using mosaicking compared to a LC-OCT handheld probe.
Conclusions:
LC-OCT allowed the architectural and cellular description of different types of melanocytic lesions. LC-OCT showed a high correlation with histopathology (vertical sections) and RCM (horizontal sections) in melanocytic lesions. Diagnostic criteria in RCM were similar to those in LC-OCT.
3D cell cultures are widely used in biomedical research for the recapitulation of in vivo microenvironments. Viability assessment and monitoring of these intricate conformations remain an open problem as standard cell viability protocols based on colorimetry or microscopy are not directly applicable to intact 3D samples. Optical coherence tomography (OCT) has been explored extensively for subsurface structural and quasi-functional analysis of 3D cell cultures and tissue. Recent studies of dynamic OCT as a source of cellular contrast have found qualitative associations with necrosis in cell spheroids, suggesting potential as a viability marker. We present empirical and validated evidence for dynamic OCT as a quantitative indicator of cell viability in 3D cultures. We analysed over 240 MCF-7 cancer cell spheroids with dynamic OCT and corresponding viability measurements using the trypan blue exclusion assay. Significant effects of common reagents Dimethyl sulfoxide (DMSO) and Phosphate-Buffered Saline (PBS) on OCT readouts were noted. We proposed a regression-based OCT brightness normalisation technique that removed reagent-induced OCT intensity biases and helped improve correspondence to the viability assay. These results offer a quantitative biological foundation for further advances of dynamic OCT as a novel non-invasive modality for 3D culture monitoring.
The prevalence of skin cancer has been increasing for the last few decades. Abnormal growth of cells forms skin lesions, which if not treated at the earliest, may turn into cancer. With the advancement in technology, computer-aided or remote diagnosis is possible, but a lot of efforts are required. An exclusive survey of the work done is required to consolidate the information regarding the various methods adopted to date and to ascertain future opportunities. In this paper, we have reviewed major works that have been proposed to automate the diagnosis of melanoma using dermoscopic images.
This article provides an overview of the progress made in skin imaging using two emerging imaging modalities, optical coherence tomography (OCT) and photoacoustic imaging (PAI). Over recent years, these technologies have significantly advanced our understanding of skin structure and function, offering non-invasive and high-resolution insights previously unattainable. The review begins by briefly describing the fundamental principles of how OCT and PAI capture images. It then explores the evolving applications of OCT in dermatology, ranging from diagnosing skin disorders to monitoring treatment responses. This article continues by briefly describing the capabilities of PAI imaging, and how PAI has been used for melanoma and non-melanoma skin cancer detection and characterization, vascular imaging, and more. The third section describes the development of multimodal skin imaging systems that include OCT, PAI, or both modes. A comparative analysis between OCT and PAI is presented, elucidating their respective strengths, limitations, and synergies in the context of skin imaging.
This chapter the reviews current and potential non-invasive laboratory (research) methods to assess the vascular dysfunction associated with Raynaud’s phenomenon (RP). Discussion encompasses prerequisites for imaging and measurement including the benefit of dynamic challenge in addition to baseline measurements. Techniques examined include laser Doppler modalities, infrared thermography, Doppler ultrasound, finger systolic pressure measurement and plethysmography. Each technique is described in terms of its theory, followed by a review of physiological and treatment studies in patients with RP. These techniques mainly assess blood flow (directly or indirectly) and oxygenation. These techniques are able to differentiate between patients with primary or secondary RP. Evidence suggests they are suitable techniques to monitor disease severity and response to treatment, although some require further validation. A more centralised approach to perfusion-based protocol design and analysis has enabled validation of certain methods paving the way for multicentre phase II clinical trials. Several new techniques offer further options for better differentiation between patient groups (recently with a focus on early secondary RP), ambulatory monitoring and measurement of other functional measures such as oxidative stress.
Port wine stain (PWS) is a congenital vascular malformation that commonly occurs on the face and neck. Currently, the main treatments for port wine stain are pulsed dye laser (PDL) and photodynamic therapy (PDT). However, the efficacy evaluation of PWS mostly relies on the subjective judgement of clinicians, and it is difficult to accurately respond to many small changes after treatment. Therefore, some non-invasive and efficient efficacy assessment methods are also needed. With the continuous development of technology, there are currently many visualisation instruments to evaluate PWS, including dermoscopy, VISIA-CR™ system, reflectance confocal microscopy (RCM), high-frequency ultrasound (HFUS), optical coherence tomography (OCT), Photoacoustic imaging (PAI), laser speckle imaging (LSI) and laser Doppler imaging (LDI). Among them, there are simple and low-cost technologies such as dermoscopy and the VISIA-CR™ system, but they may not be able to observe the deeper structures of PWS. At this time, combining techniques such as HFUS and OCT to increase penetration depth is crucial to evaluate PWS. In the future, the combination of these different technologies could help overcome the limitations of a single technology. This article provides a systematic overview of non-invasive methods for evaluating treatment efficacy in port wine stains and summarises their advantages and disadvantages.
This review examines the biological physics of intracellular transport probed by the coherent optics of dynamic light scattering from optically thick living tissues. Cells and their constituents are in constant motion, composed of a broad range of speeds spanning many orders of magnitude that reflect the wide array of functions and mechanisms that maintain cellular health. From the organelle scale of tens of nanometers and upward in size, the motion inside living tissue is actively driven rather than thermal, propelled by the hydrolysis of bioenergetic molecules and the forces of molecular motors. Active transport can mimic the random walks of thermal Brownian motion, but mean-squared displacements are far from thermal equilibrium and can display anomalous diffusion through Lévy or fractional Brownian walks. Despite the average isotropic three-dimensional environment of cells and tissues, active cellular or intracellular transport of single light-scattering objects is often pseudo-one-dimensional, for instance as organelle displacement persists along cytoskeletal tracks or as membranes displace along the normal to cell surfaces, albeit isotropically oriented in three dimensions. Coherent light scattering is a natural tool to characterize such tissue dynamics because persistent directed transport induces Doppler shifts in the scattered light. The many frequency-shifted partial waves from the complex and dynamic media interfere to produce dynamic speckle that reveals tissue-scale processes through speckle contrast imaging and fluctuation spectroscopy. Low-coherence interferometry, dynamic optical coherence tomography, diffusing-wave spectroscopy, diffuse-correlation spectroscopy, differential dynamic microscopy and digital holography offer coherent detection methods that shed light on intracellular processes. In health-care applications, altered states of cellular health and disease display altered cellular motions that imprint on the statistical fluctuations of the scattered light. For instance, the efficacy of medical therapeutics can be monitored by measuring the changes they induce in the Doppler spectra of living ex vivo cancer biopsies.
光学相干层析成像（OCT）能够无损获得微米级空间分辨率的样品截面信息，在眼科、血管内科等临床诊疗研究和应用中起到了重要的作用。利用 OCT 测量光场的幅度可以获得样本的三维结构信息，如眼底视网膜的分层结构，但对组织特异性、血流、力学特性等功能信息的作用有限。基于相位、偏振态、波长等光场参量的 OCT 功能成像技术应运而生，如多普勒 OCT、OCT 弹性成像、偏振敏感 OCT、可见光 OCT 等。其中，基于光场幅度动态变化的 OCT 功能成像技术具有显著的鲁棒性和系统复杂度优势，已经在临床无标记血管造影中获得成功。此外，应用于三维血流流速测量的动态光散射 OCT、具有无标记组织/细胞特异性显示能力的动态 OCT、能够监控热物理治疗温度场的 OCT 温度层析成像等，已经成为了 OCT 功能成像的技术前沿。综述基于光场幅度动态变化的 OCT 功能成像技术的原理、实现和应用，分析了所面临的技术挑战，并展望了未来发展方向。
Zusammenfassung
Kutane zystische Läsionen ( n = 35) wurden mit optischer Kohärenztomographie untersucht. Zysten waren sichtbar als hyporeflektive rundliche Raumforderung mit klarer Abgrenzung unter teils verdünnter Epidermis. Epidermalzysten, trichilemmale Zysten und Hidrozystome hatten einen linearen Rand, der das Zystenepithel darstellt, während mukoide Pseudozysten keinen linearen Rand aufwiesen. Trichilemmal- und Epidermoidzysten wiesen zudem einen hyperreflektiven Inhalt auf, welcher Keratin entspricht. Durch die Visualisierung des Randsaums und des Inhalts der Zyste war es möglich, zwischen verschiedenen Entitäten von Zysten zu differenzieren.
Purpose of review:
To describe the clinical significance of and the diagnostic approach to Raynaud phenomenon (RP) in the peripheral extremities and the heart.
Recent findings:
Nailfold capillaroscopy has recently been standardized in an expert consensus paper. Abnormal capillaroscopy in combination with specific autoantibody profiles and clinical signs are highly predictive of progression of RP to systemic sclerosis (SSc). Magnetic resonance imaging (MRI) can also perform tissue characterization of both the extremities and the heart. Microvascular wall abnormalities detected using nailfold capillaroscopy in patients with SSc may lead to deposition of erythrocyte-derived iron, due to microhemorrhages, which may predispose to fibrosis. MRI can assess the presence of iron using T2∗ measurements.
Summary:
RP is a hallmark of the microvasculopathy in SSc and can affect both the peripheral extremities and the heart. Nailfold capillaroscopy is the current gold standard for the evaluation of the peripheral microvasculature. Other imaging modalities include thermography, laser Doppler-derived methods, 99mTc-pertechnetate hand perfusion scintigraphy, power Doppler ultrasonography, dynamic optical coherence tomography, MRI, and photoacoustic imaging, but these are currently not widely used. Cardiac RP can be investigated with positron emission tomography or cardiovascular magnetic resonance, with the latter offering the additional possibility of tissue characterization and iron content quantification secondary to microhemorrhages.
Objectives:
A clinical study to investigate the effectiveness of pulsed dye laser (PDL) versus Nd:YAG laser in the treatment of telangiectasias, spider veins and cherry angiomas. Dynamic optical coherence tomography (D-OCT) was introduced as an innovative follow-up tool for evaluation of blood flow within superficial vessels and to allow visualization of morphological changes of the vasculature in vivo. The final aim of this study was to demonstrate a possible treatment benefit comparing both laser types.
Materials and methods:
Vessel structures of 102 skin lesions were documented photographically and dermoscopically. Subsequently, lesions were imaged using optical coherence tomography before laser therapy (a), directly after the treatment (p) and after a follow-up 4-6 weeks after laser treatment. All lesions were treated using either a 595 nm PDL or a 1064 nm Nd:YAG laser. Two main vessel parameters, namely density and diameter, and their possible changes during follow-up were observed in 150/300/500 µm penetration depth using D-OCT and were subsequently compared between both treatment groups. Other analyzed vessel parameters were depth of the plexus, mean diameter, mean density, top edge of the vessel, columns, and spikes.
Results:
Both laser types are suitable options for the treatment of vascular skin lesions, with the most significant effect on cherry angiomas. PDL shows better results treating smaller vessels in upper skin regions, in comparison to Nd:YAG laser, achieving better results on deeper vessels, like spider veins. Using the applied laser settings, there was no statistically significant effect on telangiectasias.
Conclusion:
D-OCT represents a new, noninvasive imaging method to evaluate blood flow and vessel morphology in the follow-up of telangiectasias, spider veins, and cherry angiomas, which underwent laser therapy.
Objectives:
Artificial dermal scaffold (ADS) has undergone rapid development and been increasingly used for treating skin wound in clinics due to its good biocompatibility, controllable degradation, and low risk of disease infection. To obtain good treatment efficacy, ADS needs to be monitored longitudinally during the treatment process. For example, scaffold-tissue fit, cell in-growth, vascular regeneration, and scaffold degradation are the key properties to be inspected. However, to date, there are no effective, real-time, and noninvasive techniques to meet the requirement of the scaffold monitoring above.
Materials and methods:
In this study, we propose to use optical coherence tomography (OCT) to monitor ADS in vivo through three-dimensional imaging. A swept source OCT system with a handheld probe was developed for in vivo skin imaging. Moreover, a cell in-growth, vascular regeneration, and scaffold degradation rate (IRDR) was defined with the volume reduction rate of the scaffold's collagen sponge layer. To measure the IRDR, a semiautomatic image segmentation algorithm was designed based on U-Net to segment the collagen sponge layer of the scaffold from OCT images.
Results:
The results show that the scaffold-tissue fit can be clearly visualized under OCT imaging. The IRDR can be computed based on the volume of the segmented collagen sponge layer. It is observed that the IRDR appeared to a linear function of the time and in addition, the IRDR varied among different skin parts.
Conclusion:
Overall, it can be concluded that OCT has a good potential to monitor ADS in vivo. This can help guide the clinicians to control the treatment with ADS to improve the therapy.
Imaging technology plays a critical role in clinical practice and modern medical research. Optical coherence tomography (OCT) enables a noninvasive and depth‐resolved in vivo volumetric visualization of internal microstructure of biology, has become one of the most innovative and fascinating optical imaging methods in the last decades. Besides, OCT angiography (OCTA) is an important functional modality of OCT, capable of label‐free generating images of vasculature perfusion down to capillary level within tissue beds. In this chapter, the overview and basic theory of OCT are presented, and the state‐of‐the‐art OCT technology and its applications are comprehensively summarized and highlighted. In addition, the OCTA combining shape, inverse SNR (iSNR) and decorrelation features (SID‐OCTA) is systematically reviewed, mainly including the OCTA contrast origins, SID‐OCTA imaging, quantification and applications.
Optical Coherence Tomography (OCT) is an emerging non-invasive method for oral diagnostics, proving to be a practicable device for epithelial and subepithelial evaluation. The potential validity of OCT in oral cancer assessment has been explored but, to date, there are very few investigations conducted with a systematic comparison between clinical/histological and OCT parameters, especially in strict reference to the anatomical site-codification of the oral mucosa. In this regard, our study performed a two-steps evaluation (in vivo OCT and histological investigations) of suspected OSCCs, progressively recruited, using as references the OCT images of the same site-coded healthy mucosa, to provide as much as possible site-specific determinants. Thirty histologically confirmed OSCCs were recruited. Specific OCT mucosal features (SEL—Stratified Epithelial Layer; BM—Basement Membrane; LP—Lamina Propria) were registered and processed using the SRQR (Standards for Reporting Qualitative Research) statement. The systematic dual descriptive OCT analysis revealed that OSCC scans present a complete alteration of epithelial (KL, SEL) and subepithelial (BM, LP) layers with a site-specificity characteristic; moreover, peculiar OCT configurations such as “icicle-like” structures could be strongly suggestive of neoplastic infiltration. This study supports the OCT use for the development of more specific optical structural models applied to oral carcinogenesis.
BACKGROUND Optical coherence tomography (OCT) is an optical imaging technique that may be useful
in diagnosis of non-melanoma skin cancer (NMSC).
OBJECTIVES To describe OCT features in NMSC such as actinic keratosis (AK) and basal cell carcinoma
(BCC) and in benign lesions and to assess the diagnostic accuracy of OCT in differentiating NMSC from
benign lesions and normal skin.
METHODS AND MATERIALS OCT and polarization-sensitive (PS) OCT from 104 patients were studied.
Observer-blinded evaluation of OCT images from 64 BCCs, 1 baso-squamous carcinoma, 39 AKs, two
malignant melanomas, nine benign lesions, and 105 OCT images from perilesional skin was performed;
50 OCT images of NMSC and 50 PS-OCT images of normal skin were evaluated twice.
RESULTS Sensitivity was 79% to 94% and specificity 85% to 96% in differentiating normal skin from
lesions. Important features were absence of well-defined layering in OCT and PS-OCT images and dark
lobules in BCC. Discrimination of AK from BCC had an error rate of 50% to 52%.
CONCLUSION OCT features in NMSC are identified, but AK and BCC cannot be differentiated. OCT
diagnosis is less accurate than clinical diagnosis, but high accuracy in distinguishing lesions from normal
skin, crucial for delineating tumor borders, was obtained.
The authors have indicated no significant interest with commercial supporters.
The diagnostic criteria for basal cell carcinoma (BCC) using optical coherence tomography (OCT) have been described previously, but the clinical value of these findings has been unknown.
The aim of this study was to investigate the diagnostic value of OCT for BCC in a typical clinical setting. The primary efficacy endpoint was a diagnosis of BCC for each lesion. Secondary endpoints were the diagnosis of other possible conditions.
This was an observational, prospective, multi-centre study in which consecutive patients with non-pigmented pink lesions suspicious for BCC underwent clinical assessment, dermoscopy, and OCT with the diagnosis recorded at each stage. Once all diagnoses had been recorded, histological results were disclosed. One hundred and sixty-four patients with 256 lesions were recruited. Histology was missing for 21 lesions, leaving 235 lesions in 155 patients for analysis.
Sixty per cent of lesions (141/235) were identified as BCC by histology. A slight increase of sensitivity was noted following OCT, which did not reach statistical significance. Specificity increased significantly from 28.6% by clinical assessment to 54.3% using dermoscopy and to 75.3% with the addition of OCT (p<0.0001). Positive predictive value for diagnosis of BCC using OCT was 85.2% (95% CI: 78.6 - 90.4); negative predictive value was 92.1% (95% CI: 83.6 - 97.0). The accuracy of diagnosis for all lesions increased from 65.8% with clinical evaluation to 76.2% following additional dermoscopy and to 87.4% with the addition of OCT.
OCT significantly improved diagnostic specificity for BCC compared to clinical assessment and dermoscopy alone. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
The ability to phenotype wounds for the purposes of assessing severity, healing potential and treatment is an important function of evidence-based medicine. A variety of optical technologies are currently in development for noninvasive wound assessment. To varying extents, these optical technologies have the potential to supplement traditional clinical wound evaluation and research, by providing detailed information regarding skin components imperceptible to visual inspection. These assessments are achieved through quantitative optical analysis of tissue characteristics including blood flow, collagen remodeling, hemoglobin content, inflammation, temperature, vascular structure and water content. Technologies that have, to this date, been applied to wound assessment include: near infrared imaging, thermal imaging, optical coherence tomography, orthogonal polarization spectral imaging, fluorescence imaging, laser Doppler imaging, microscopy, spatial frequency domain imaging, photoacoustic detection, and spectral/hyperspectral imaging. We present a review of the technologies in use or development for these purposes with three aims: 1) providing basic explanations of imaging technology concepts, 2) reviewing the wound imaging literature, and 3) providing insight into areas for further application and exploration. Noninvasive imaging is a promising advancement in wound assessment and all technologies require further validation. This article is protected by copyright. All rights reserved.
© 2015 by the Wound Healing Society.
We demonstrate the in vivo assessment of human scars by parametric imaging of birefringence using polarization-sensitive optical coherence tomography (PS-OCT). Such in vivo assessment is subject to artifacts in the detected birefringence caused by scattering from blood vessels. To reduce these artifacts, we preprocessed the PS-OCT data using a vascular masking technique. The birefringence of the remaining tissue regions was then automatically quantified. Results from the scars and contralateral or adjacent normal skin of 13 patients show a correspondence of birefringence with scar type: the ratio of birefringence of hypertrophic scars to corresponding normal skin is 2.2 +/- 0.2 (mean +/- standard deviation), while the ratio of birefringence of normotrophic scars to normal skin is 1.1 +/- 0.4. This method represents a new clinically applicable means for objective, quantitative human scar assessment. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
Optical coherence tomography (OCT) is a noninvasive imaging technique that allows real-time high-definition cross-sectional visualization of tissues. Conventional OCT was introduced in dermatology in 1997 and has shown benefit in evaluating malignant neoplasms and inflammatory skin disorders.¹,2 High-definition OCT (HD-OCT) scanners have recently been developed; they provide a higher resolution than conventional OCT and horizontal, in additional to vertical, sectional imaging, which conventional OCT does not provide.
Since its introduction in dermatology in the late 1990s optical coherence tomography (OCT) has been used to study many skin diseases, in particular non-melanoma skin cancer and it s precursors. Special attention has been paid to superficial basal cell carcinoma (BCC), and a number of smaller observational studies have been pub-lished. The diagnostic criteria for BCC of these studies are systematically reviewed. A systemic review of English language studies was performed using PubMed, Google Scholar and Royal Danish Library, to search for primary papers on OCT and BCC. The references of retrieved papers were searched by hand for further relevant papers. A total of 39 papers were identified (search date: 2014-01-15). 22 were excluded because they did not meet the inclusion criteria, leaving 17 papers for analysis. In 100 % of the studies, rounded dark structures in the upper dermis surrounded by a hyperreflective halo possibly surrounded by a hyporeflective border and disruption of epidermal layering were described. In 53 % of the reports a hypore-flective lateral tumour border was described. A range of other features were mentioned in a minority of the studies. It is suggested that these diagnostic criteria could be characteristic for identifying BCC lesions using OCT.
The formation of burn-scar tissue in human skin profoundly alters, among other things, the structure of the dermis. We present a method to characterize dermal scar tissue by the measurement of the near-infrared attenuation coefficient using optical coherence tomography (OCT). To generate accurate en face parametric images of attenuation, we found it critical to first identify (using speckle decorrelation) and mask the tissue vasculature from the three-dimensional OCT data. The resulting attenuation coefficients in the vasculature-masked regions of the dermis of human burn-scar patients are lower in hypertrophic (3.8±0.4 mm-1) and normotrophic (4.2±0.9 mm-1) scars than in contralateral or adjacent normal skin (6.3±0.5 mm-1). Our results suggest that the attenuation coefficient of vasculature-masked tissue could be used as an objective means to assess human burn scars.
High-definition optical coherence tomography (HD-OCT) is a non-invasive in vivo imaging technique with cellular resolution based on the principle of conventional optical coherence tomography. The objective of this study was to evaluate HD-OCT for its ability to identify architectural patterns and cytologic features of melanocytic lesions. All lesions were examined by one observer clinically and using dermoscopy. Cross-sectional HD-OCT images were compared with histopathology. En face HD-OCT images were compared with reflectance confocal microscopy (RCM). Twenty-six melanocytic lesions of 26 patients were imaged. Identification of architectural patterns in cross-sectional mode and cytologic features of pigmented cells in the epidermis, dermo-epidermal junction, papillary dermis, and superficial reticular dermis in the en face mode was possible by HD-OCT. HD-OCT provides morphological imaging with sufficient resolution and penetration depth to discriminate architectural patterns and cytologic features of pigmented cells in epidermis and dermis. The method appears to offer the possibility of additional three-dimensional structural information complementary to that of RCM, albeit at a slightly lower lateral resolution. The diagnostic potential of HD-OCT regarding malignant melanoma is not high enough for ruling out a diagnosis of malignant melanoma.
The lateral resolution of Fourier domain optical coherence tomography (FD-OCT) systems is limited by the depth of focus that can be achieved over the desired imaging depth at the chosen wavelength. Various solutions have been proposed such as Bessel beams and computational methods; however these suffer from various practical drawbacks. We present a novel optical set-up involving multiple optical channels that does not suffer from these drawbacks and delivers at least double the resolution of a single beam system. The theory of this approach is discussed, also the realisation in a practical laboratory system, measurement results and initial application in assessing oesophageal cancers and pre-cancers.
Background:
Skin involvement is of major prognostic value in systemic sclerosis (SSc) and often the primary outcome in clinical trials. Nevertheless, an objective, validated biomarker of skin fibrosis is lacking. Optical coherence tomography (OCT) is an imaging technology providing high-contrast images with 4 μm resolution, comparable with microscopy ('virtual biopsy'). The present study evaluated OCT to detect and quantify skin fibrosis in SSc.
Methods:
We performed 458 OCT scans of hands and forearms on 21 SSc patients and 22 healthy controls. We compared the findings with histology from three skin biopsies and by correlation with clinical assessment of the skin. We calculated the optical density (OD) of the OCT images employing Matlab software and performed statistical analysis of the results, including intraobserver/interobserver reliability, employing SPSS software.
Results:
Comparison of OCT images with skin histology indicated a progressive loss of visualisation of the dermal-epidermal junction associated with dermal fibrosis. Furthermore, SSc affected skin showed a consistent decrease of OD in the papillary dermis, progressively worse in patients with worse modified Rodnan skin score (p<0.0001). Additionally, clinically unaffected skin was also distinguishable from healthy skin for its specific pattern of OD decrease in the reticular dermis (p<0.001). The technique showed an excellent intraobserver and interobserver reliability (intraclass correlation coefficient >0.8).
Conclusions:
OCT of the skin could offer a feasible and reliable quantitative outcome measure in SSc. Studies determining OCT sensitivity to change over time and its role in defining skin vasculopathy may pave the way to defining OCT as a valuable imaging biomarker in SSc.
In scars arising from burns, objective assessment of vascularity is important in the early identification of pathological scarring, and in the assessment of progression and treatment response. We demonstrate the first clinical assessment and automated quantification of vascularity in cutaneous burn scars of human patients in vivo that uses optical coherence tomography (OCT). Scar microvasculature was delineated in three-dimensional OCT images using speckle decorrelation. The diameter and area density of blood vessels were automatically quantified. A substantial increase was observed in the measured density of vasculature in hypertrophic scar tissues (38%) when compared against normal, unscarred skin (22%). A proliferation of larger vessels (diameter≥100 μm) was revealed in hypertrophic scarring, which was absent from normal scars and normal skin over the investigated physical depth range of 600 μm. This study establishes the feasibility of this methodology as a means of clinical monitoring of scar progression.
Vascular endothelial growth factor (VEGF) is known to play a critical role in the development of non-melanoma skin cancers. VEGF is a potent pro-angiogenic factor and it is elevated in mouse and human skin tumors. The use of transgenic and knockout mice has shown that VEGF is essential for tumor development in multiple models of skin carcinogenesis and, until recently, the mechanism of action has been primarily attributed to the induction of angiogenesis. However, additional roles for VEGF have now been discovered. Keratinocytes can respond directly to VEGF, which could influence skin carcinogenesis by altering proliferation, survival, and stemness. In vivo studies have shown that loss of epidermal VEGFR-1 or neuropillin-1 inhibits carcinogenesis, indicating that VEGF can directly affect tumor cells. Additionally, VEGF has been shown to promote tumor growth by recruiting macrophages to skin tumors, which likely occurs through VEGFR-1. Overall, these new studies show that VEGF carries out functions beyond its well-established effects on angiogenesis and highlight the need to consider these alternative activities when developing new treatments for non-melanoma skin cancer.
A technique called optical coherence tomography (OCT) has been developed
for noninvasive cross-sectional imaging in biological systems. OCT uses
low-coherence interferometry to produce a two-dimensional image of
optical scattering from internal tissue microstructures in a way that is
analogous to ultrasonic pulse-echo imaging. OCT has longitudinal and
lateral spatial resolutions of a few micrometers and can detect
reflected signals as small as ~10-10 of the incident optical
power. Tomographic imaging is demonstrated in vitro in the peripapillary
area of the retina and in the coronary artery, two clinically relevant
examples that are representative of transparent and turbid media,
respectively.
The inhibition of VEGF signaling with antibodies or small molecules achieves clinical benefits in diverse solid malignancies. Nonetheless, therapeutic effects are usually not sustained, and most patients eventually succumb to progressive disease, indicating that antiangiogenic strategies require additional optimization. Vaccination with lethally irradiated, autologous tumor cells engineered to secrete granulocyte-macrophage colony stimulating factor (GM-CSF) and antibody blockade of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) trigger a tumor vasculopathy in some long-term responding subjects. These reactions are characterized by disrupted tumor blood vessels in association with lymphocyte and granulocyte infiltrates and zonal areas of ischemic tumor necrosis. However, the mechanisms underlying this immune-mediated destruction of the tumor vasculature remain to be clarified. Here, we show that GM-CSF-secreting tumor cell vaccines and CTLA-4 blockade elicit a functionally important humoral reaction against multiple angiogenic cytokines. Antibodies to angiopoietin-1 and angiopoietin-2 block Tie-2 binding, downstream signaling, endothelial cell tube formation, and macrophage chemotaxis. Antibodies to macrophage inhibitory factor (MIF) attenuate macrophage Tie-2 expression and matrix metalloproteinase-9 (MMP-9) production. Together, these results delineate an immunotherapy-induced host response that broadly targets the angiogenic network in the tumor microenvironment.
The cutaneous microcirculation is organized as two horizontal plexuses. One is situated 1-1.5 mm below the skin surface and the other is at the dermal-subcutaneous junction. Ascending arterioles and descending venules are paired as they connect the two plexuses. From the upper layer, arterial capillaries rise to form the dermal papillary loops that represent the nutritive component of the skin circulation. There are sphincter-like smooth muscle cells at the point where the ascending arterioles divide to form the arteriolar component of the upper horizontal plexus. At the dermal-subcutaneous junction, there are collecting veins with two cusped valves that are oriented to prevent the retrograde flow of blood. Laser Doppler flowmetry has demonstrated vasomotion of red cell flux localized to the sites of ascending arterioles. The simultaneous recording by laser Doppler flowmetry of red cell flux and the concentration of moving red blood cells from individual sites allows one to construct topographic maps of these two values. These two maps, based on initial studies using correlative skin biopsies, can define 1 mm3 volumes of skin that are predominantly arteriolar in composition, venular in composition, or essentially devoid of all microvascular elements. The electron and light microscopic features that define the microvascular segments, when coupled with that ability of laser Doppler flowmetry to define the predominant microvascular segments under the probe, allow one to study both the mechanisms of normal physiologic states and the pathogenetic mechanisms underlying pathologic skin disorders in which the microvasculature plays a predominant role.
We report the first application of high-speed fiber-based polarization sensitive optical coherence tomography (PS-OCT) to image burned tissue in vivo. Thermal injury denatures collagen in skin and PS-OCT can measure the reduction in collagen birefringence using depth resolved changes in the polarization state of light propagated in, and reflected from, the tissue. Stokes vectors were calculated for each point in a scan and birefringence relative to incident polarization determined using four incident polarization states. Using a high-speed fiber-based PS-OCT system on rat skin burned for varying periods of time, a correlation between birefringence and actual burn depth determined by histological analysis was established. In conclusion, PS-OCT has potential use for noninvasive assessment of burn depth.
Optical coherence tomography (OCT) is a high-speed, three-dimensional optical imaging technique that provides cross-sectional images of tissue microstructure with contrast based on the changes in the optical properties (refractive index) of the tissue. In contrast to conventional microscopy, OCT provides the ability to image tissue with resolution on the order of 10 μm within the first 1–2 mm from the tissue surface to provide nondestructive tissue analysis. The ability to acquire non- and minimally invasive depth-resolved microscopic images at speeds ≥ 100 frames per second has propelled OCT as a viable clinical and research tool for various fields including the assessment of ophthalmic, cardiovascular, gastrointestinal, and pulmonary diseases. In this article, we describe image formation and important considerations required to read and utilize OCT imaging and then review the ability to visualize pathology and pathophysiology within these organ systems in vivo.
Background:
Brimonidine is a selective α2 adrenergic receptor agonist with potent vasoconstrictive activity topically used for treatment of facial flushing and erythema caused by rosacea. Direct evidence for the in vivo morphology changes in skin vessels induced by topical application of brimonidine is limited. Dynamic optical coherence tomography is a novel technology that combines conventional OCT with information on flow and thereby provides supplementary information about the microvasculature. Dynamic OCT is non-invasive and creates high-resolution in vivo images of skin to a depth of maximum 2 mm.
Objective:
The objective of this study was to examine and describe micro-morphological skin vessel changes in normal skin exposed to brimonidine gel using Dynamic OCT.
Materials and methods:
A total of 35 healthy subjects from three European clinical dermatology centres were included in the study. A normal skin area on the cheek was marked and clinically photographed. Brimonidine gel 0.33% was applied on the area and chromaticity measurements; laser speckle measurements and Dynamic OCT images were acquired at baseline and 60 min after application. The images were subsequently described in detail and quantitatively analysed.
Results:
All the measurement tools (chromaticity, laser speckle, Dynamic OCT showed highly significant (P < 0.001) quantitative differences in blood flow before and after the application of brimonidine. In 58% of the subjects the Dynamic OCT images showed notable changes in the morphology of the blood vessel network after application of brimonidine including a marked reduction in the abundance and the diameter of the blood vessels.
Conclusion:
The vascular constriction induced by topical brimonidine gel 0.33% was visualized in vivo by Dynamic OCT and confirmed by quantitative measurements and analyses. This study shows that Dynamic OCT can detect characteristic morphological changes in the vessels and may potentially aid the monitoring of treatment effects on skin vessels following topical or laser treatment.
Preliminary studies have described morphological features of basal cell carcinoma (BCC) imaged by high-definition optical coherence tomography (HD-OCT) and suggested that this technique may aid in its diagnosis and management. However, systematic studies evaluating the accuracy of HD-OCT for the diagnosis of BCC are lacking.
The aim of this study was to identify three-dimensional (3-D) HD-OCT features able i) to distinguish BCC from clinical BCC imitators and ii) to discriminate between the most common BCC subtypes. Based on these particular features, a diagnostic algorithm will be suggested.
A total of 50 histopathologically confirmed BCCs (18 superficial, 19 nodular, 13 infiltrative) were imaged by HD-OCT at the centre of the lesion prior to standard surgical excision and subsequent histopathological analysis. Fifty images of clinical BCC imitators were also retrieved as a 'pitfalls' group.
The simultaneous presence of grey/dark subepidermal (hemi-spherical) or intradermal lobulated structure(s) presenting a typical cockade feature in both HD-OCT modes was a significant feature for BCC diagnosis. Features discriminating between BCC subtypes were location of the roof of BCC lobules, vascular pattern of the papillary plexus and stretching effect on the stroma. Clinical BCC imitators such as actinic keratosis, compound and intradermal naevi, amelanotic melanoma, sebaceous hyperplasia and small haemangioma could be differentiated from BCC by means of HD-OCT.
This study provides a thorough description of 3-D HD-OCT features that can permit discrimination of BCC from clinical BCC imitators and differentiation of BCC subtypes. Based on these features, a diagnostic algorithm is proposed which requires additional validation, but enhances current understanding of the morphological correlates of HD-OCT images in skin.
© 2015 European Academy of Dermatology and Venereology.
High-definition optical coherence tomography (HD-OCT) scanners have recently been developed. We assessed micromorphological HD-OCT correlates of benign naevi (BN) and malignant melanoma (MM). 28 BN and 20 MM were studied using HD-OCT and histology. Epidermal honeycomb/cobblestone pattern, regular junctional cell nests, and edged papillae are more often observed in BN, whereas fusion of rete ridges, pagetoid cells and junctional and/or dermal nests with atypical cells are more frequently seen in MM. A high overlap of HD-OCT features in BN and MM was observed and in 20% of MM we did not find evidence for malignancy in OCT images at all. Using HD-OCT it is possible to visualize architectural and cellular alterations of melanocytic skin lesions. The overlap of HD-OCT features seen in BN and MM and the absence of suspicious HD-OCT features in some MM represents an important limitation of HD-OCT affecting the sensitivity of HD-OCT in diagnosing MM. High-definition optical coherence tomography and the corresponding vertically sectioned histology of a compound naevus.
Background:
Collagen deposition disorders such as hypertrophic scars, keloids and scleroderma can be associated with significant stigma and embarrassment. These disorders often constitute considerable impairment to quality of life, with treatment posing to be a substantial challenge. Optical coherence tomography (OCT) provides a non-invasive, easily applicable bedside optical imaging method for assessment of the skin. It is hypothesized that OCT imaging may be useful in assessing fibrosis to avoid additional biopsies that could potentially worsen the scarring.
Method:
Thirty-three patients with ordinary scars, hypertrophic scars, keloid scarring, lichen sclerosus et atrophicus and localized or systemic scleroderma were recruited for this pilot study. Affected tissue and adjacent healthy skin were scanned using OCT and digitally photographed. Density measurements were performed in ImageJ on OCT images from scleroderma patients, both systemic and morphea (10 patients), keloid patients (10 patients) and healthy skin adjacent to keloids (10 patients).
Results:
OCT images of scarring diseases showed varying degrees of disruption to the skin architecture. OCT characteristics were identified for each lesion type. Hypertrophic scars displayed an increased vascularity and signal-rich bands correlating to excessive collagen deposition. Keloids depicted a disarray of hyper-reflective areas primarily located in the upper dermis. Additionally, the dermis displayed a heterogeneous morphology without indications of any vascular supply or lymphatic network. In contrast to keloids, scleroderma displayed a more cohesive backscattering indicating a difference in density of collagen or other dermal structures. OCT images demonstrated no significant differences between mean density measurements in OCT images of scleroderma, keloid and healthy skin (P = 0.07).
Conclusion:
The OCT imaging appears to identify different scarring mechanisms, and therefore be of potential use in the assessment of outcomes following non-invasive therapy of e.g. early or progressive lesions.
Background: Patients with moderate to severe rosacea often seek treatment to reduce erythema and vascular markings. Few studies have looked at the effectiveness of the novel treatment, brimonidine topical gel 0.33%, trademark name Mirvaso®, in the treatment of rosacea. We report the use of optical coherence tomography (OCT) scanning to monitor the effectiveness of Mirvaso® on in vivo skin. OCT is a non-invasive optical imaging technique that can provide high-resolution imaging of vessel and cellular morphology. OCT may be useful as a pre-treatment assessment tool for identifying possible morphologic features in the skin that may serve as outcome predictors. OCT may also serve as a monitoring tool in the treatment of rosacea.
Objective: To examine and describe how OCT skin morphology changes when exposed to brimonidine topical gel 0.33% in the treatment of erythematotelangiectatic rosacea.
Methods: Normal in vivo telangiectasias and erythematous patches and papules were examined prior to treatment clinically, dermatoscopically, and through OCT scans. Brimonidine topical gel 0.33% was applied to the face and OCT images were acquired at defined time intervals: baseline; immediately (<5 minutes) after application; 4 hours after application; and after 2 weeks' once daily application. OCT morphology was then described.
Results: OCT imaging showed an increase in the mean gray value (MGV), a measure of dermal reflectivity, corresponding to a decrease in dermal edema. MGV measurements for the nasal telangiectasia were: baseline, MGV 10,471 (standard deviation [SD] 6,847); immediate, MGV 15,634 (SD 8,983); after 4 hours, MGV 16,357 (SD 7,647); and after 2 weeks, MGV 15,505 (SD 6,870). MGV measurements for the chin erythema were: baseline, MGV 8,850 (SD 4,969); immediate, MGV 10,799 (SD 5,266); after 4 hours, MGV 12,419 (SD 6,714); and after 2 weeks, MGV 13,395 (SD 6,170). No significant change in vessel lumen diameter was appreciated. Vessel lumen diameter for the facial papule ranged from 0.13 mm at baseline, 0.09 mm immediately after treatment, 0.09 mm after 4 hours, and 0.11 mm after 2 weeks.
Conclusions: OCT scanning showed a decrease in the dermal hyporeflectivity of the dermis consistent with a decrease in dermal edema. The OCT scans obtained did not show any significant change in vessel lumen diameter. These results may reflect an increase in vascular tone, which can be attributable to the clinical improvement and decreased erythema noted in the patient. This technology could potentially be used for the non-invasive in vivo monitoring of other topical treatments.
J Drugs Dermatol. 2014;13(7):821-826.
Background:
The current guidelines for the management of basal cell carcinoma (BCC) suggest a different therapeutic approach according to histopathologic subtype. Although dermatoscopic and confocal criteria of BCC have been investigated, no specific studies were performed to evaluate the distinct reflectance confocal microscopy (RCM) aspects of BCC subtypes.
Objectives:
To define the specific dermatoscopic and confocal criteria for delineating different BCC subtypes.
Methods:
Dermatoscopic and confocal images of histopathologically confirmed BCCs were retrospectively evaluated for the presence of predefined criteria. Frequencies of dermatoscopic and confocal parameters are provided. Univariate and adjusted odds ratios were calculated. Discriminant analyses were performed to define the independent confocal criteria for distinct BCC subtypes.
Results:
Eighty-eight BCCs were included. Dermatoscopically, superficial BCCs (n=44) were primarily typified by the presence of fine telangiectasia, multiple erosions, leaf-like structures, and revealed cords connected to the epidermis and epidermal streaming upon RCM. Nodular BCCs (n=22) featured the classic dermatoscopic features and well outlined large basaloid islands upon RCM. Infiltrative BCCs (n=22) featured structureless, shiny red areas, fine telangiectasia, and arborizing vessels on dermatoscopy and dark silhouettes upon RCM.
Limitations:
The retrospective design.
Conclusion:
Dermatoscopy and confocal microscopy can reliably classify different BCC subtypes.
Background
Dermatoscopy increases both sensitivity and specificity for melanoma diagnosis. Reflectance confocal microscopy (RCM) is a non invasive technique which complements dermatoscopy, in the evaluation of equivocal lesions at cellular resolution.Objectives
The purpose of the study was to prospectively determine the potential impact of confocal microscopy when implemented in a routine melanoma diagnosis workflow.Patients and methodsPatients referred to a single Melanoma Clinic were consecutively enrolled. At dermatoscopy, patients were referred to one of the following pathways: 1- No further examination; 2- RCM examination: atypical lesion/s were referred for either: i) RCM Documentation (lesions with consistent suspicious clinical/dermatoscopic criteria, already qualified and scheduled for surgical excision) or ii) RCM Consultation for equivocal lesions, where RCM diagnosis would determine lesion definite outcome (excision or digital follow-up).ResultsRCM examination was performed for 41% of 1005 patients enrolled. In 2/3 of these cases RCM influenced the lesion outcome. The systematic application of RCM for equivocal lesions saved over 50% benign lesions from unnecessary excision. The number needed to excise (NNE) a melanoma was 6.8 with RCM examination, compared to a hypothetical 14.6 without RCM evaluation.ConclusionRCM as a second level –level examination to dermatoscopy proved to be highly accurate in diagnosis and reduced the number of unnecessary excisions. Improved accuracy, considering that RCM enabled the detection of the 6 melanomas (2%) in the group of 308 lesions eligible for follow-up, also minimizes the risk of referring a melanoma to digital dermatoscopy monitoring, and potentially losing the patient to follow-up.This article is protected by copyright. All rights reserved.
High-definition optical coherence tomography (HD-OCT) scanners have recently been developed providing significantly higher resolution than conventional OCT.
To assess the relationship between recently defined histopathological HD-OCT correlates of basal cell carcinomas (BCC) and possible predictors for the most common tumour subtypes.
For HD-OCT imaging, we used the Skintell(®) device (Agfa Healthcare, Mortsel, Belgium). Twenty-five BCCs were histopathologically (including vertical as well horizontal haematoxylin and eosin and Alcian blue sectioning) confirmed and correlated with HD-OCT images.
In the en-face mode, lobulated nodules were seen in 21 of the 25 lesions (84%), peripheral rimming in 18 (25/72%), epidermal disarray also in 18 (25/72%) and variably refractile stroma in 22 BCC (25/88%). In the slice imaging mode, we observed in 19 of 25 (76%) a BCC destruction of layering. Both in the slice and en-face mode a significant correlation was observed between peritumoural rimming and grey/dark oval structures and lobulated nodules. Alcian blue stains showed peritumoural mucin deposits correlating with peripheral rimming around the tumour nodules. In a logistic regression model, we neither observed for solid BCC nor for superficial BCC subtypes significant independent micromorphological HD-OCT predictors.
In agreement with recent studies we have demonstrated that HD-OCT using slice and en-face imaging modes can visualize histopathological correlates of BCC, and potentially aid non-invasive diagnostics. However, using HD-OCT correlates assessed it was not possible to predict superficial or solid BCC subtypes. For the first time we have shown that peripheral rimming is a HD-OCT correlate of peritumoural mucin deposition. This article is protected by copyright. All rights reserved.
Photodynamic therapy with methyl aminolaevulinate (MAL-PDT) is a widely used non-invasive treatment modality for non-melanoma skin cancer (NMSC). The outcome of MAL-PDT is usually primarily evaluated clinically. Optical coherence tomography (OCT) is a non-invasive imaging technology based on interferiometry. OCT has been proven to provide high accuracy in identifying NMSC lesions and performing thickness measurements of thin tumours.
To describe the OCT morphology in in-vivo NMSC lesions during MAL-PDT treatment and to investigate the use of OCT in evaluating the response of MAL-PDT treated NMSC lesions METHODS: A total of 18 biopsy-proven basal cell carcinomas and actinic keratoses were monitored by OCT during 2 sessions of MAL-PDT treatment. At 3-months follow-up the patients were assessed both by OCT and clinically. If the clinical and OCT evaluation came to different conclusions on recurrence of the lesion, patients were followed more closely at clinical appointments for up to one year after the PDT treatment RESULTS: All lesions displayed at least one OCT characteristic before MAL-PDT treatment. At 3 months follow-up, recurrence was suspected clinically in 5/18 cases, with OCT in 7/18 cases. OCT correctly identified all of the partial responses also found by the clinical examinations. In both cases where recurrence was only found in OCT, this was subsequently confirmed by histology.
Our study suggests that OCT identified 29% more recurrences than clinical examination alone. OCT can detect subclinical residual NMSC lesions after MAL-PDT treatment and may therefore be an accurate tool for early detection of residual lesional tissue.
Optical coherence tomography (OCT) is a non-invasive imaging modality that is transforming clinical diagnosis in dermatology and other medical fields. OCT provides a cross-sectional evaluation of the epidermis and dermis and allows in vivo imaging of skin collagen. Upregulated collagen content is a key feature of fibrotic skin diseases. These diseases are often managed by the practitioner's subjective assessment of disease severity and response to therapies. The purpose of this review is to provide an overview of the principles of OCT and present available evidence on the ability of OCT to image skin collagen in vivo for the diagnosis and management of diseases characterized by skin fibrosis. We review OCT studies that characterize the collagen content in normal skin and fibrotic skin diseases including systemic sclerosis and hypertrophic scars secondary to burn, trauma, and other injury. We also highlight several limitations of OCT and suggest enhancements to improve OCT imaging of skin fibrosis. We conclude that OCT imaging has the potential to serve as an objective, non-invasive measure of collagen's status and disease progression for use in both research trials and clinical practice. The future use of OCT imaging as a quantitative imaging biomarker of fibrosis will help identify fibrosis and facilitate clinical examination in monitoring response to treatment longitudinally without relying on serial biopsies. The use of OCT technology for quantification of fibrosis is in the formative stages and we foresee tremendous growth potential, similar to the ultrasound development paradigm that evolved over the past 30 years.
To explore the application of optical coherence tomography (OCT) imaging of basal cell carcinomas (BCC) and actinic keratosis (AK) before, during and after imiquimod treatment and the ability of OCT to predict treatment outcome.
The study subjects were 20 patients with biopsy-verified BCC (9) or AK (11). Patients were OCT-scanned before, after 1 and 4 weeks of imiquimod treatment and after 3 months. Lesions were identified clinically and with OCT. Thickness and morphology of the lesions were recorded at each visit. Any remaining lesions were biopsied at follow-up.
Complete data sets were available for 16 patients (8 women and 8 men aged 52-82 years), four in-compliant patients were excluded. OCT identified all lesions. Previously suggested OCT-criteria identified 5/8 BCCs. Crusting, ulceration and active treatment significantly reduced image quality. All BCCs cleared, but at follow-up residual structures were seen clinically in 4 cases. OCT and histology both ruled out residual BCC. For AKs significant thinning occurred after 1 week of treatment (P = 0.04). Imiquimod cleared 2/8 AKs, and significantly decreased the thickness of all lesions (P = 0.02).
OCT could identify superficial BCC and AK before treatment. Monitoring during imiquimod treatment revealed impaired image quality most likely caused by inflammation, crusting and ulceration. On follow-up, OCT showed thinning of AKs indicating effect of treatment. All treated BCCs cleared, but where residual tissue was suspected clinically this could be ruled out by OCT.
Burn depth determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS- OCT), to assess burn depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.
The monitoring of wound-healing processes is indispensable for the therapeutic effectiveness and improved care of chronic wounds. Histological sections provide the best morphological assessment of wound recovery, but cause further tissue destruction and increase the risk of infection. Therefore, it is reasonable to apply a diagnostic tool that allows a non-invasive and reliable observation of morphological changes in wound healing.
Optical coherence tomography (OCT) is an imaging technique for in vivo evaluation of skin diseases with a resolution close to histopathology. The aim of this study was to investigate whether OCT is suited to display the phases of wound healing. For this purpose, six patients with chronic wounds were objectively characterized by OCT during a period of 2 weeks.
Comparable results between histological findings and OCT were achieved. OCT allowed the detection of partial loss of the epidermis, vasoconstriction, vasodilatation and epithelialization.
Consequently, OCT could be a potential non-invasive diagnostic tool for the characterization and monitoring of cutaneous wound-healing processes over time.
Vascular malformations commonly occur in the facial region, and can be associated with significant stigma and embarrassment. Studies have shown that even recommended light-based treatments do not always result in complete clearance. This indicates the need for more accurate pre-treatment assessment of vessel morphology to optimize treatment settings and identify possible morphological predictors of the outcome. Fourteen patients (six males, eight females, and aged 37-66 years) with the diagnosis of telangiectasias were enrolled and were all scanned with OCT and digitally photographed before and minutes after IPL treatment. OCT images of the telangiectasias before treatment were displayed as hyporeflective/signal poor bands clearly demarcated from the surrounding tissue. Minutes after treatment, OCT images demonstrated two different reactions. (1) Narrow hyperreflective bands surrounding the vessels, which may indicate edema or insufficient coagulation. (2) Hyperreflective signals within the lumen of the vessels, compatible with the expected irreversible microthrombus formation in the vessels. OCT imaging is capable of real-time assessment of tissue damage during light and laser treatment, including visualization of the perivascular changes. This may offer a more dynamic, more complete understanding of the efficacy and potential outcome of the treatment process. It is hypothesized that these immediate changes may correlate to longer-term treatment outcome.
Summary Background With the continued development of noninvasive therapies for basal cell carcinoma (BCC) such as photodynamic therapy and immune therapies, noninvasive diagnosis and monitoring become increasingly relevant. High-definition optical coherence tomography (HD-OCT) is a high-resolution imaging tool, with micrometre resolution in both transversal and axial directions, enabling visualization of individual cells up to a depth of around 570 μm, and filling the imaging gap between conventional optical coherence tomography (OCT) and reflectance confocal microscopy (RCM).
Objectives We sought to determine the feasibility of detecting BCC by this technique using criteria defined for RCM and conventional OCT and compared with histology.
Methods In this pilot study skin lesions of 21 patients with a histologically proven BCC were imaged by HD-OCT just before excision and images analysed qualitatively.
Results Features for four different BCC subtypes were described in both transverse and axial directions. In general, these features were subepidermal or intradermal aggregations of cells. These islands or trabeculae were surrounded by a less refractile border corresponding with palisading and peritumoral mucin production. There was a pronounced architectural disarray of the epidermis. A variably refractile stroma together with abundant dilated peritumoral blood vessels was present. These features were comparable with histological features for each patient.
Conclusions Using features already suggested by RCM and conventional OCT, the study implies that HD-OCT facilitates in vivo diagnosis of BCC and allows the distinction between different BCC subtypes for increased clinical utility.
BACKGROUND
The prognosis of squamous cell carcinoma (SCC) of the skin is directly related to the development of metastases or local recurrence. This is affected by numerous factors, most of which are independent: clinical tumor size, histopathologic tumor thickness, depth of penetration, degree of cell differentiation, degree of keratinization, location, and immunosuppression. The determination of whether desmoplasia, previously described in only one case of SCC, constitutes an additional prognostic factor was the objective of this study.METHODS
The study was performed prospectively on 594 SCCs from 509 patients. All of the factors mentioned earlier were present. Forty-four SCCs were identified by light microscopy as desmoplastic due to their prominent trabecular growth patterns, narrow columns of atypical epithelial cells, and marked desmoplastic stromal reaction, in some cases with perineural and perivascular invasion. Follow-up ranged from 4 to 10 years (median, 5.3 years).RESULTSAll tumors in the study patient population were treated using the paraffin section method of micrographic surgery. The 44 desmoplastic SCCs were found to metastasize 6 times more often than the remaining 550 tumors (22.7% vs. 3.8%), with 10 times as many local recurrences (27.3% vs. 2.6%).CONCLUSIONS
Desmoplasia is a highly significant (P < 0.001) prognostic factor for SCCs and is associated with the development of metastases or recurrence. Cancer 1997; 79:915-9. © 1997 American Cancer Society.
Non-melanoma skin cancer (NMSC) is rarely fatal but is now the most common malignancy occurring in white populations, accounting for 70% of the cost of managing skin cancer. Optical coherence tomography (OCT) has the potential to improve diagnostic accuracy and help delineate pre-surgical margins in NMSC. Its widespread clinical acceptance awaits the accumulation of evidence from studies of direct histological comparisons.
In this study, seventy-eight subjects presenting with skin lesions, including 28 NMSCs, were imaged using the VivoSight® OCT scanner and a biopsy taken. Haemotoxylin and eosin stained histology sections were compared with the OCT images.
The depth of superficial basal cell carcinoma (BCC) lesions (<1 mm) can be measured accurately using OCT. A low-strength OCT signal at the periphery of the cell nests seen in superficial and nodular BCC is identified as corresponding to cellular palisading. A weak inverse linear correlation (r2 = 0.3) is found between the optical attenuation coefficient measured on OCT and the nuclear-cytoplasmic ratio (N/C) of cells determined from histology.
OCT has clinical value in providing accurate dimensional measurement of superficial BCC and in identifying the presence of peripheral palisading in nodular BCC.
The accurate determination of burn depth is critical in the clinical management of burn wounds. Polarization-sensitive optical coherence tomography (PS-OCT) has been proposed as a potentially non-invasive method for determining burn depth by measuring thermally induced changes in the structure and birefringence of skin, and has been investigated in pre-clinical burn studies with animal models and ex vivo human skin. In this study, we applied PS-OCT to the in-vivo imaging of two pediatric burn patients. Deep and superficial burned skins along with contralateral controls were imaged in 3D. The imaging size was 8 mm × 6 mm × 2 mm in width, length, and depth in the air respectively, and the imaging time was approximately 6 s per volume. Superficially burned skins exhibited the same layered structure as the contralateral controls, but more visible vasculature and reduced birefringence compared to the contralateral controls. In contrast, a deeply burned skin showed loss of the layered structure, almost absent vasculature, and smaller birefringence compared to superficial burns. This study suggested the vasculature and birefringence as parameters for characterizing burn wounds.
Background:
Optical coherence tomography (OCT) is an optical imaging technique that may be useful in diagnosis of non-melanoma skin cancer (NMSC).
Objectives:
To describe OCT features in NMSC such as actinic keratosis (AK) and basal cell carcinoma (BCC) and in benign lesions and to assess the diagnostic accuracy of OCT in differentiating NMSC from benign lesions and normal skin.
Methods and materials:
OCT and polarization-sensitive (PS) OCT from 104 patients were studied. Observer-blinded evaluation of OCT images from 64 BCCs, 1 baso-squamous carcinoma, 39 AKs, two malignant melanomas, nine benign lesions, and 105 OCT images from perilesional skin was performed; 50 OCT images of NMSC and 50 PS-OCT images of normal skin were evaluated twice.
Results:
Sensitivity was 79% to 94% and specificity 85% to 96% in differentiating normal skin from lesions. Important features were absence of well-defined layering in OCT and PS-OCT images and dark lobules in BCC. Discrimination of AK from BCC had an error rate of 50% to 52%.
Conclusion:
OCT features in NMSC are identified, but AK and BCC cannot be differentiated. OCT diagnosis is less accurate than clinical diagnosis, but high accuracy in distinguishing lesions from normal skin, crucial for delineating tumor borders, was obtained.
Background/aims: Optical coherence tomography (OCT) is a non-invasive technique for morphological investigation of tissue. Since its development in the late 1980s it is mainly used as a diagnostic tool in ophthalmology. For examination of a highly scattering tissue like the skin, it was necessary to modify the method. Early studies on the value of OCT for skin diagnosis gave promising results.
Methods: The OCT technique is based on the principle of Michelson interferometry. The light sources used for OCT are low coherent superluminescent diodes operating at a wavelength of about 1300 nm. OCT provides two-dimensional images with a scan length of a few millimeters (mm), a resolution of about 15 μm and a maximum detection depth of 1.5 mm. The image acquisition can be performed nearly in real time. The measurement is non-invasive and with no side effects.
Results: The in vivo OCT images of human skin show a strong scattering from tissue with a few layers and some optical inhomogeneities. The resolution enables the visualization of architectural changes, but not of single cells. In palmoplantar skin, the thick stratum corneum is visible as a low-scattering superficial well defined layer with spiral sweat gland ducts inside. The epidermis can be distinguished from the dermis. Adnexal structures and blood vessels are low-scattering regions in the upper dermis. Skin tumors show a homogenous signal distribution. In some cases, tumor borders to healthy skin are detectable. Inflammatory skin diseases lead to changes of the OCT image, such as thickening of the epidermis and reduction of the light attenuation in the dermis. A quantification of treatment effects, such as swelling of the horny layer due to application of a moisturizer, is possible. Repeated measurements allow a monitoring of the changes over time.
Conclusion: OCT is a promising new bioengineering method for investigation of skin morphology. In some cases it may be useful for diagnosis of skin diseases. Because of its non-invasive character, the technique allows monitoring of inflammatory diseases over time. An objective quantification of the efficacy and tolerance of topical treatment is also possible. Due to the high resolution and simple application, OCT is an interesting addition to other morphological techniques in dermatology.
Tumor cell extravasation is a critical step in the metastatic cascade and requires interaction between the tumor cell and the endothelium. Although cancer progression depends on a complex network of mechanisms, including inflammation and coagulation, the involvement of tumor-induced endothelium activation and the subsequent release of procoagulatory factors in this process are not well understood. Using tissue sections from patients with malignant melanoma, immunofluorescence studies for the presence of von Willebrand factor (VWF) clearly demonstrated endothelium activation and the formation of ultra-large VWF fibers in these patients. In vitro analyses revealed that supernatants from highly invasive melanoma cells induced an acute endothelium activation measured by VWF, P-selectin, and angiopoietin-2 release. Proteome profiling identified vascular endothelial growth factor A (VEGF-A) as the main mediator of endothelium activation. Inhibition and knock-down of VEGF-A in melanoma cells led to a rigorous decrease in VWF exocytosis. Selective small-interfering RNA to matrix metalloproteinase-2 (MMP-2) inhibited endothelium activation, and this effect correlated with reduced VEGF-A content in the supernatants of melanoma cells. Further experiments showed that active MMP-2 regulates VEGF-A in melanoma cells on a transcriptional level via an integrin αvβ5/phosphoinositide-3-kinase-dependent pathway. In conclusion, these results indicate an important role of VEGF-A in acute endothelium activation and provide clear evidence that MMP-2 plays a pivotal role in the autocrine regulation of VEGF-A expression in melanoma cells.
Background Optical coherence tomography (OCT) allows real-time, in vivo examination of basal cell carcinoma (BCC). A new high definition OCT with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode offers additional information in the diagnosis of BCC and may potentially replace invasive diagnostic biopsies.
Objectives To define the characteristic morphologic features of BCC by using high definition optical coherence tomography (HD-OCT) compared to conventional histology.
Methods A total of 22 BCCs were examined preoperatively by HD-OCT in the en-face and slice imaging mode and characteristic features were evaluated in comparison to the histopathological findings.
Results The following features were found in the en-face mode of HD-OCT: lobulated nodules (20/22), peripheral rimming (17/22), epidermal disarray (21/22), dilated vessels (11/22) and variably refractile stroma (19/22). In the slice imaging mode the following characteristics were found: grey/dark oval structures (18/22), peripheral rimming (13/22), destruction of layering (22/22), dilated vessels (7/22) and peritumoural bright stroma (11/22). In the en-face mode the lobulated structure of the BCC was more distinct than in the slice mode compared to histology.
Conclusion HD-OCT with a horizontal and vertical imaging mode offers additional information in the diagnosis of BCC compared to conventional OCT imaging and enhances the feasibility of non-invasive diagnostics of BCC.
As angiogenesis is essential for tumor growth and metastasis, controlling tumor-associated angiogenesis is a promising tactic in limiting cancer progression. The tumor microenvironment comprises numerous signaling molecules and pathways that influence the angiogenic response. Understanding how these components functionally interact as angiogenic stimuli or as repressors and how mechanisms of resistance arise is required for the identification of new therapeutic strategies. Achieving a durable and efficient antiangiogenic response will require approaches to simultaneously or sequentially target multiple aspects of the tumor microenvironment.
Nonmelanoma skin cancer refers to a broad class of tumors, including actinic keratosis, basal cell carcinoma, and squamous cell carcinoma, and as a group these are the most frequent cancers occurring in light skinned humans. In contrast to the rarity of amelanotic melanoma, nonmelanoma skin cancer commonly lacks pigmentation. Although these tumors rarely cause death related to metastases, they commonly destroy underlying tissues and should be removed at the earliest possible stage. Dermoscopy improves the clinical diagnosis of nonpigmented skin tumors by allowing the visualization of specific vascular structures that are usually not visible to the naked eye. Dermoscopic vascular patterns of several nonmelanocytic nonpigmented skin tumors, such as sebaceous hyperplasia, seborrheic keratosis, clear cell acanthoma, Bowen disease, or nodular cystic basal cell carcinoma are highly specific, allowing a ready diagnosis in most cases. Others, such as actinic keratosis, pyogenic granuloma, or uncommon adnexal tumors, may be difficult to differentiate even with the aid of dermoscopy. For this reason, general guidelines have been established to assist in making the most appropriate management decision. In the second part of this review of dermoscopic vascular structures of nonpigmented skin tumors, the dermoscopic patterns associated with benign and malignant nonmelanocytic skin tumors and recommendations for the management of these tumors will be discussed.
Dermoscopy is a noninvasive tool that can be helpful in the diagnosis of nonpigmented skin tumors. This is because dermoscopy permits the visualization of key vascular structures that are usually not visible to the naked eye. Much work has concentrated on the identification of specific morphologic types of vessels that allow a classification into melanocytic versus nonmelanocytic and benign versus malignant nonpigmented skin tumors. Among a broad spectrum of different types of vascular patterns, six main morphologies can be identified. These are comma-like, dotted, linear-irregular, hairpin, glomerular, and arborizing vessels. With some exceptions, comma, dotted, and linear irregular vessels are associated with melanocytic tumors, while the latter three vascular types are generally indicative of keratinocytic tumors. Aside from vascular morphology, the architectural arrangement of vessels within the tumor and the presence of additional dermoscopic clues are equally important for the diagnosis. This article provides a general overview of the dermoscopic evaluation of nonpigmented skin tumors and is divided into two parts. Part I discusses the dermoscopic vascular patterns of benign and malignant melanocytic skin tumors. Part II discusses the dermoscopic vascular patterns of benign and malignant nonmelanocytic nonpigmented skin tumors. In each part, additional special management guidelines for melanocytic and nonmelanocytic nonpigmented skin tumors, respectively, will be discussed.
Optical coherence tomography (OCT) is an emerging imaging technology based on light reflection. It provides real-time images with up to 2-mm penetration into the skin and a resolution of approximately 10 microm. It is routinely used in ophthalmology. The normal skin and its appendages have been studied, as have many diseases. The method can provide accurate measures of epidermal and nail changes in normal tissue. Skin cancer and other tumors, as well as inflammatory diseases, have been studied and good agreement found between OCT images and histopathological architecture. OCT also allows noninvasive monitoring of morphologic changes in skin diseases and may have a particular role in the monitoring of medical treatment of nonmelanoma skin cancer. The technology is however still evolving and continued technological development will necessitate an ongoing evaluation of its diagnostic accuracy. Several technical solutions are being pursued to further improve the quality of the images and the data provided, and OCT is being integrated in multimodal imaging devices that would potentially be able to provide a quantum leap to the imaging of skin in vivo.
To identify criteria for the diagnosis of squamous cell carcinoma (SCC) and actinic keratosis (AK) by in vivo reflectance confocal microscopy (RCM).
Prospective RCM imaging of lesions suspected clinically and/or dermoscopically to be SCC or AK, followed by RCM assessment of the biopsy-proven SCCs and AKs.
Private skin cancer clinic, Plantation, Florida. Patients A total of 38 lesions in 24 patients were assessed, including 7 AKs, 25 SCCs in situ, 3 invasive SCCs, and 3 keratoacanthomas. Interventions Prior to undergoing biopsy, all lesions were assessed by RCM.
Mosaic RCM images at the stratum corneum level revealed scale in 29 SCCs (95%) and in all 7 AKs. Polygonal nucleated cells at the stratum corneum were seen in 3 SCCs (10%) and 1 AK (14%). All 38 cases displayed an atypical honeycomb and/or a disarranged pattern of the spinous-granular layer of the epidermis; round nucleated cells were seen in the spinous-granular layer in 20 SCCs (65%) and 1 AK (14%). Round blood vessels in the superficial dermis were seen in 28 SCCs (90%) and 5 AKs (72%).
An increasing frequency of abnormal RCM features can be observed across the spectrum of keratinocytic neoplasias. The presence of an atypical honeycomb or a disarranged pattern of the spinous-granular layer, round nucleated cells at the spinous-granular layer, and round blood vessels traversing through the dermal papilla are the key RCM features of SCC.
The prognosis of squamous cell carcinoma (SCC) of the skin is directly related to the development of metastases or local recurrence. This is affected by numerous factors, most of which are independent: clinical tumor size, histopathologic tumor thickness, depth of penetration, degree of cell differentiation, degree of keratinization, location, and immunosuppression. The determination of whether desmoplasia, previously described in only one case of SCC, constitutes an additional prognostic factor was the objective of this study.
The study was performed prospectively on 594 SCCs from 509 patients. All of the factors mentioned earlier were present. Forty-four SCCs were identified by light microscopy as desmoplastic due to their prominent trabecular growth patterns, narrow columns of atypical epithelial cells, and marked desmoplastic stromal reaction, in some cases with perineural and perivascular invasion. Follow-up ranged from 4 to 10 years (median, 5.3 years).
All tumors in the study patient population were treated using the paraffin section method of micrographic surgery. The 44 desmoplastic SCCs were found to metastasize 6 times more often than the remaining 550 tumors (22.7% vs. 3.8%), with 10 times as many local recurrences (27.3% vs. 2.6%).
Desmoplasia is a highly significant (P < 0.001) prognostic factor for SCCs and is associated with the development of metastases or recurrence.
Optical coherence tomography (OCT) is a new diagnostic method for tissue characterization.
We investigated normal and pathologic structures in human skin in several locations to evaluate the potential application of this technique to dermatology.
Based on the principle of low-coherence interferometry, cross-sectional images of the human skin can be obtained in vivo with a high spatial resolution of about 15 microns. Within a penetration depth of 0.5 to 1.5 mm, structures of the stratum corneum, the living epidermis, and the papillary dermis can be distinguished.
Different layers could be detected that were differentiated by induction of experimental blisters and by comparison with corresponding histologic sections. Furthermore, OCT images of several skin diseases and tumors were obtained.
OCT is a promising new imaging method for visualization of morphologic changes of superficial layers of the human skin. It may be useful for noninvasive diagnosis of bullous skin diseases, skin tumors, and in vivo investigation of pharmacologic effects.
Although the pathological features of basal cell carcinoma are well known, there is no generally agreed classification of the subtypes of this tumour. Certain histological subtypes are associated with indistinct clinical margins, inadequate primary excisions and frequent recurrences, and these must be recognized and reported by pathologists so that the most appropriate therapy is given. The current classification of subtypes of basal cell carcinoma is discussed and reference made to the rarer forms of this tumour.