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Three-dimensional ultrasound imaging of the rotator cuff: Spatial compounding and tendon thickness measurement
Abstract
Three-dimensional (3-D) volume reconstructions of the shoulder rotator cuff were generated from freehand ultrasound (US) scans acquired with a magnetic tracking system. Image stacks acquired with lateral overlap from multiple acoustic windows were spatially compounded to provide an extended representation of the rotator cuff tendons. A semiautomated technique was developed for measuring rotator cuff thickness from the 3-D compound volumes. Scans of phantoms and volunteer subjects were used to evaluate the accuracy and repeatability of the thickness measurements. For an in vitro phantom with known thickness, the mean difference between the true value and the automatic measurements was 0.05 +/- 0.28 mm. Thickness measurements made manually from 2-D images and automatically from 3-D volumes were different by 0.03 +/- 0.44 mm in vitro and -0.06 +/- 0.36 in vivo. Repeated thickness measurements in vivo differed by 0.06 +/- 0.36 mm. The 3-D measurement technique offers a promising method for evaluating rotator cuff tendons.
... Ils ont estimé l'erreur moyenne du modèle à 0.45 mm.Il est intéressant de noter qu'ils ont enveloppé la prothèse avec de la pâte à modeler. Cette dernière est, d'un point de vue radiologique, équivalent à l'os.Plusieurs autres auteurs(Leotta, D. and R. Martin (2000),Prevrhal et al. (1999), Kirket al. (2001)) utilisent comme objet d'étude le fantôme de dimensions connues. Constatant, par ailleurs, que le principe reste toujours comparable à ce qui a déjà été présenté, nous portons maintenant notre intérêt vers d'autres méthodes qui considèrent des formes irrégulières et des dimensions inconnues. ...
... enue.Nous remarquons que les marqueurs sont de dimensions assez importantes pour modifier la précision des mesures. En fait, le positionnement précis de l'outil de mesure devient difficile. Par confre, l'utilisation de plusieurs mesures et manipulateurs permet d'obtenir une moyenne de lectures qui permet d'obtenir une bonne précision et exactitude.Leotta et Martin (2000) évaluent la capacité de l'imagerie 3D par ulfrasons pour la mesure d'épaisseur de tendon. Leur approche utilise à la fois un fantôme et un fémur humain. Le fantôme est un tube de 5cm de diamèfre avec une paroi d'épaisseur uniforme. Le fémur est placé à l'intérieur et le tout est balayé par ulfrasons. Cette méthode présente l'avantage d' ...
... The Pnn method, which belongs to the forward reconstruction class of methods, has been extensively discussed in the literature [3], [5], [9], [15], [16], [19], [24]- [29]. ...
... In most cases, however, the average value is used because of its smoothing or speckle-reducing nature. volumes reconstructed us-ing average values appear to be less noisy than volumes reconstructed using maximum values, which can be explained by the spatial compounding effect [5], [23]. Using average values also has a useful property of preserving the gray-value histogram of the underlying data, which may be practical for additional post-processing steps performed on the ultrasound volume. ...
... Spatial compounding in two dimensions [14], [15] or three dimensions [16], [17] typically means averaging the intensities at common points of intersection without regarding the imaging geometry. In [18], a 3-D volume compounding method was proposed to reconstruct the shoulder rotator cuff. This method accommodated the ultrasound beam direction for fusing dense ultrasound volumes. ...
... We have sparse data (typically, data are acquired at a 3-6 rotational increment), and therefore a voxel (intensity) based compounding approach is not feasible. Instead, in this paper, we use an adaptation of [18] to do feature-based compounding. We first segment endocardial feature points in the 2-D T data, then fuse all the feature points from multiple acoustic windows in a 3-D reference frame using a compounding weight determined by the imaging geometry. ...
A new method is proposed to reconstruct and analyze the left ventricle (LV) from multiple acoustic window three-dimensional (3-D) ultrasound acquired using a transthoracic 3-D rotational probe. Prior research in this area has been based on one acoustic window acquisition. However, the data suffers from several limitations that degrade the reconstruction and reduce the clinical value of interpretation, such as the presence of shadow due to bone (ribs) and air (in the lungs) and motion of the probe during the acquisition. In this paper, we show how to overcome these limitations by automatically fusing information from multiple acoustic window sparse-view acquisitions and using a position sensor to track the probe in real time. Geometric constraints of the object shape, and spatiotemporal information relating to the image acquisition process, are used in new algorithms for 1) grouping endocardial edge cues from an initial image segmentation and 2) defining a novel reconstruction method that utilizes information from multiple acoustic windows. The new method has been validated on a phantom and three real heart data sets. In the phantom study, one finger of a latex glove was scanned from two acoustic windows and reconstructed using the new method. The volume error was measured to be less than 4%. In the clinical case study, 3-D ultrasound and magnetic resonance imaging (MRI) scanning were performed on the same healthy volunteers. Quantitative ejection fractions (EFs) and volume-time curves over a cardiac cycle were estimated using the new method and compared to cardiac MRI measurements. This showed that the new method agrees better with MRI measurements than the previous approach we have developed based on a single acoustic window. The EF errors of the new method with respect to MRI measurements were less than 6%. A more extensive clinical validation is required to establish whether these promising first results translate to a method suitable for routine clinical use.
... The Pnn method, which belongs to the forward reconstruction class of methods, has been extensively discussed in the literature [3], [5], [9], [15], [16], [19], [24]- [29]. ...
... In most cases, however, the average value is used because of its smoothing or speckle-reducing nature. volumes reconstructed us-ing average values appear to be less noisy than volumes reconstructed using maximum values, which can be explained by the spatial compounding effect [5], [23]. Using average values also has a useful property of preserving the gray-value histogram of the underlying data, which may be practical for additional post-processing steps performed on the ultrasound volume. ...
A new method for 3-D ultrasound volume reconstruction using tracked freehand 3-D ultrasound is proposed. The method is based on solving the forward volume reconstruction problem using direct interpolation of high-resolution ultrasound B-mode image frames. A series of ultrasound B-mode image frames (an image series) is acquired using the freehand scanning technique and position sensing via optical tracking equipment. The proposed algorithm creates additional intermediate image frames by directly interpolating between two or more adjacent image frames of the original image series. The target volume is filled using the original frames in combination with the additionally constructed frames. Compared with conventional volume reconstruction methods, no additional filling of empty voxels or holes within the volume is required, because the whole extent of the volume is defined by the arrangement of the original and the additionally constructed B-mode image frames. The proposed direct frame interpolation (DFI) method was tested on two different data sets acquired while scanning the head and neck region of different patients. The first data set consisted of eight B-mode 2-D frame sets acquired under optimal laboratory conditions. The second data set consisted of 73 image series acquired during a clinical study. Sample volumes were reconstructed for all 81 image series using the proposed DFI method with four different interpolation orders, as well as with the pixel nearest-neighbor method using three different interpolation neighborhoods. In addition, volumes based on a reduced number of image frames were reconstructed for comparison of the different methods' accuracy and robustness in reconstructing image data that lies between the original image frames. The DFI method is based on a forward approach making use of a priori information about the position and shape of the B-mode image frames (e.g., masking information) to optimize the reconstruction procedure and to reduce computation times and memory requirements. The method is straightforward, independent of additional input or parameters, and uses the high-resolution B-mode image frames instead of usually lower-resolution voxel information for interpolation. The DFI method can be considered as a valuable alternative to conventional 3-D ultrasound reconstruction methods based on pixel or voxel nearest-neighbor approaches, offering better quality and competitive reconstruction time.
... Clearly this approach works correctly when the B-scans are quasiparallel; however, under other circumstances, for example, when the volume consists of several sweeps in different directions, the selection of a representative Key frame may be difficult to do, or such a representative frame may even not exist; in addition, it will usually not be the best solution in terms of minimizing the amount of data needed to represent the scanned volume. As far as the grid spacing is concerned, several authors pose the problem as a trade-off between resolution and size of the reconstructed volume (Barry et al. 1997; Rohling et al. 1998; Leotta and Martin 2000) and the specific value is chosen a priori. The third step deals with the reconstruction itself (i.e., resampling the information into a regular grid). ...
... As is stated by Rohling et al. (1997), every freehand system has to deal with compounding in some manner, because it is almost unavoidable that the scan planes intersect. A great activity has been carried out regarding spatial US compounding (Burckhardt 1978; Wagner et al. 1988 ) and, more specifically, in 3-D freehand ultrasound (Detmer et al. 1994; Rohling et al. 1998; Leotta and Martin 2000). Averaging has been traditionally the compounding operation, because the speckle signal may be partially filtered out; theoretically, the improvement in the signal to noise ratio (SNR) may reach proportionality with the number of samples that are averaged. ...
Several techniques have been described in the literature in recent years for the reconstruction of a regular volume out of a series of ultrasound (US) slices with arbitrary orientations, typically scanned by means of US freehand systems. However, a systematic approach to such a problem is still missing. This paper focuses on proposing a theoretical framework for the 3-D US volume reconstruction problem. We introduce a statistical method for the construction and trimming of the sampling grid where the reconstruction will be carried out. The results using in vivo US data demonstrate that the computed reconstruction grid that encloses the region-of-interest (ROI) is smaller than those obtained from other reconstruction methods in those cases where the scanning trajectory deviates from a pure straight line. In addition, an adaptive Gaussian interpolation technique is studied and compared with well-known interpolation methods that have been applied to the reconstruction problem in the past. We find that the proposed method numerically outperforms former proposals in several control studies; subjective visual results also support this conclusion and highlight some potential deficiencies of methods previously proposed.
... The major sources of error in 3D reconstruction are the scanning procedure itself and the segmentation process postscanning that outlines the area of interest. The accuracies of similar 3D ultrasound systems have been assessed in vitro on isolated cadaver muscles (Delcker et al. 1999) and on phantom measurements (Leotta and Martin 2000;Ferrari et al. 2006), but not in situ. Repeatability has been investigated in vitro (Delcker et al. 1999) and for the rotator cuff tendons in humans in situ (Leotta and Martin 2000). ...
... The accuracies of similar 3D ultrasound systems have been assessed in vitro on isolated cadaver muscles (Delcker et al. 1999) and on phantom measurements (Leotta and Martin 2000;Ferrari et al. 2006), but not in situ. Repeatability has been investigated in vitro (Delcker et al. 1999) and for the rotator cuff tendons in humans in situ (Leotta and Martin 2000). ...
Muscle morphology determines muscle function. An objective method to determine muscle volume in vivo will facilitate understanding of basic muscle function and will also provide a valuable tool for the clinician to assess the effectiveness of treatment. In this method-validation study, it is hypothesised that a freehand 3-D ultrasonography system provides a noninvasive method that allows the determination of muscle volume with high accuracy and precision. To test the hypotheses, repeated measurements were performed (1) on cadaver muscles in situ, (2) isolated muscles and (3) live animals. Volume measurements performed with 3-D ultrasonography were compared with measurements based on computed tomography and the water displacement method. The results of this study showed that 3-D ultrasound provided excellent precision and accuracy in the measurements on the isolated muscles and good precision in vivo. It is concluded that 3-D ultrasonography is an innovative technique that allows objective determination of muscle volume in vivo. (E-mail:[email protected]
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... Spatial compounding in two dimensions [14], [15] or three dimensions [16], [17] typically means averaging the intensities at common points of intersection without regarding the imaging geometry. In [18], a 3-D volume compounding method was proposed to reconstruct the shoulder rotator cuff. This method accommodated the ultrasound beam direction for fusing dense ultrasound volumes. ...
... We have sparse data (typically, data are acquired at a 3–6 rotational increment), and therefore a voxel (intensity) based compounding approach is not feasible. Instead, in this paper, we use an adaptation of [18] to do feature-based compounding. We first segment endocardial feature points in the 2-D T data, then fuse all the feature points from multiple acoustic windows in a 3-D reference frame using a compounding weight determined by the imaging geometry. ...
... The 2-D images were reformatted into a 3-D gray-scale volume based on the 3-D position and orientation of each image. 50 A total of 4740 2-D images were acquired, and an isotropic volume of 283 Â 281 Â 100 voxels was reconstructed at 1-mm resolution. The echo interface of the aberrating layer was manually outlined at 4mm steps in the reconstructed volume data, 49 and the outlines were processed to create a 3-D mesh reconstruction of the aberrating layer surface. ...
Phase aberration induced by soft tissue inhomogeneities often complicates high-intensity focused ultrasound (HIFU) therapies by distorting the field and, previously, we designed and fabricated a bilayer gel phantom to reproducibly mimic that effect. A surface pattern containing size scales relevant to inhomogeneities of a porcine body wall was introduced between gel materials with fat- and muscle-like acoustic properties—ballistic and polyvinyl alcohol gels. Here, the phantom design was refined to achieve relevant values of ultrasound absorption and scattering and make it more robust, facilitating frequent handling and use in various experimental arrangements. The fidelity of the interfacial surface of the fabricated phantom to the design was confirmed by three-dimensional ultrasound imaging. The HIFU field distortions—displacement of the focus, enlargement of the focal region, and reduction of focal pressure—produced by the phantom were characterized using hydrophone measurements with a 1.5 MHz 256-element HIFU array and found to be similar to those induced by an ex vivo porcine body wall. A phase correction approach was used to mitigate the aberration effect on nonlinear focal waveforms and enable boiling histotripsy treatments through the phantom or body wall. The refined phantom represents a practical tool to explore HIFU therapy systems capabilities.
... The second case (ABS2) was scanned in B-mode at weeks 2, 3 and 4 with the 3D image capture system. These tracked scans were used to create gray-scale volume reconstructions by compiling the series of 2D images in a regular 3D grid (Leotta and Martin 2000). The total number of images collected were 1212, 1783, and 341 for the scans at weeks 1 through 3, respectively. ...
Abscesses are walled-off collections of infected fluids that often develop as complications in the setting of surgery and trauma. Abscess care depends on size, location, composition and complexity, among other patient factors. The goal of this work is to describe, using the latest ultrasound imaging technologies, the progression of abscess development in a porcine animal model. Intramuscular or subcutaneous injections of bacteria plus dextran particles as an irritant led to identifiable abscesses over a 2- to 3-week period. The abscesses were imaged at least weekly with B-mode, 3D B-mode, shear-wave elastography (SWE) and color flow imaging. Mature abscesses were characterized by a well-defined core of varying echogenicity surrounded by a hypoechoic capsule that was highly vascularized on Doppler imaging. Size and shape changes during development were quantified with 3D imaging. With SWE, the lesion stiffness varied interiorly and generally decreased over time. These ultrasound features potentially provide biomarkers to facilitate improved selection of treatment strategies for abscesses.
... Returning to the ultrasound images, the 2D images were reconstructed in a regular 3D grid using spatial tracking data to create a gray-scale volume; technique details can be found in the references (Leotta and Martin 2000). The borders of the abscess and the two treatment regions were manually outlined in a series of planes viewed in orthogonal directions, and the 2D outlines were used to construct a 3D surface for each object using the MeshLab software package (Cignoni, et al. 2008). ...
Infected abscesses are walled-off collections of pus and bacteria. They are a common sequela of complications in the setting of surgery, trauma, systemic infections, and other disease states. Current treatment is typically limited to antibiotics with long-term catheter drainage, or surgical wash-out when inaccessible to percutaneous drainage or unresponsive to initial care efforts. Antibiotic resistance is also a growing concern. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. In particular, short pulses of focused ultrasound ( i . e ., histotripsy) generate mechanical damage through localized cavitation, representing a potential new paradigm for treating abscesses non-invasively, without the need for long-term catheterization and antibiotics. In this pilot study, boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses developed in a novel porcine model. Ultrasound imaging was used to evaluate abscess maturity, for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. Cavitation histotripsy was more successful in reducing the bacterial load while having a smaller treatment volume compared with boiling histotripsy. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.
... Although the 2D matrix array and free-hand scanning were utilized for the diagnosis of RCT [24], [25], their use is limited to only research purposes and cannot be used further due to the high cost of the hardware and difficulty in configuration. Therefore, a 3D US system for clinical use, which is capable of offering a large field of view for a 3D US image with a reasonable cost, should be developed for the quantitative analysis of the RCT region. ...
Rotator cuff tear (RCT) is a common injury that causes pain and disability in adults. The quantitative diagnosis of the RCT can be crucial in determining a treatment plan or monitoring treatment efficacy. Currently, only a few diagnosis tools, such as magnetic resonance imaging (MRI) and ultrasound imaging (US), are utilized for the diagnosis. Specifically, US exhibited comparable performance with MRI while offering a readily available diagnosis of RCTs at a lower cost. However, three-dimensional(3D) US and analysis of the regions are necessary to enable a better diagnosis of RCTs. Therefore, we developed a wide-field 3D US platform with a semi-automatic 3D image segmentation algorithm for 3D quantitative diagnosis of RCTs. The 3D US platform is built based on a conventional 2D US system and obtains 3D US images via linear scanning. With respect to 3D segmentation algorithm based on active contour model, frequency compounding and anisotropic diffusion methods were applied, and their effects on segmentation were discussed. The platform was used for clinical examination after evaluating the platform via the RCT-mimicking phantoms. As verified by the Dice coefficient(average DC: 0.663, volume DC: 0.723), which was approximately up to 50% higher than that obtained with conventional algorithms, the RCT regions segmented by the developed algorithm significantly matched the ground truth. The results indicated that the wide-field 3D US platform with the 3D segmentation algorithm can constitute a useful tool for improving the accuracy in the diagnosis of RCTs, and can eventually lead to better determination of treatment plans and surgical planning.
... Indeed, MRIs have been shown to be ineffective at revealing partial-thickness tears. [13][14][15][16] In fact, multiple studies have reported that MRA is far more diagnostically effective for detecting full-and partial-thickness rotator cuff but especially small full-thickness tears. [11,16,17] A previous meta-analysis [18] that utilized 65 articles suggested that MRA could provide the accuracy in detecting full-thickness tears; however, Co et al [19] contradicts this finding indicating that MRA is only applied in the cases where patients possessed labral abnormalities, as MRA only improves the sensitivity and specificity by 3% to 4% when compared with either US or MRI. ...
Background:
Numerous quantitatively based studies measuring the accuracy of 3D shoulder ultrasound (US) for the diagnosis of rotator cuff tears remain inconclusive. In order to determine how effective 3D shoulder US is for detecting rotator cuff tears, a meta-analysis was performed systematically.
Methods:
Six electronic databases, PubMed/Medline, Embase, Cochrane Library, CNKI, VIP data, and Wanfang data, were utilized to retrieve articles praising the diagnostic value of 3D shoulder US for use in detecting rotator cuff tears. After screening and diluting out the articles that met inclusion criteria to be used for statistical analysis, the pooled evaluation indexes including sensitivity, specificity, and diagnostic odds ratio (DOR) as well as the summary receiver operating characteristic curve (SROC) were calculated utilizing Meta-Disc v.1.4.
Results:
Screening determined that out of 4220, 7 studies involving a total of 282 patients were deemed viable for inclusion in the meta-analysis. The results of the analysis showed that the sensitivity and specificity were at 94% and 83%, respectively, with a DOR of 60.06, Q* index of 0.9058 and the area under SROC of 0.9609. Additionally, a satisfactory accuracy of 3D shoulder US was observed in detecting full- and partial-thickness rotator cuff tears.
Conclusion:
This meta-analysis suggests that 3D shoulder US is very effective and highly accurate to detect full-thickness rotator cuff tears, but may lack accuracy in the diagnosis of partial tears.
... The reference lists of the included articles were searched for any additional papers, with no additional papers identified. Six articles were excluded (AC Gellhorn, 2013;Arend et al., 2014;Leotta and Martin, 2000;Malanga et al., 2012;Ryan et al., 2013;Shen and Li, 2012) after screening the full text of the identified articles for reasons outlined in figure 2.The final number of articles included in this review was 22. Study ...
Background:
Diagnostic ultrasound (US) is a commonly used imaging modality for visualising tendon pathology and morphology. In comparison to magnetic resonance imaging (MRI), diagnostic US is perceived to have a higher risk of error when evaluating tendon size.
Aim:
To systematically assess the evidence regarding the Intra rater and Inter rater reliability of diagnostic US measurements of tendon size.
Data sources:
Eight electronic databases were searched using an agreed set of keywords. Studies which investigated the reliability of tendon size (thickness or cross sectional area) using diagnostic US were eligible.
Results:
Combined Inter rater and Intra rater ICC values for tendon thickness ranged from 0.45 to 0.99. Combined Inter rater and Intra rater ICC values for tendon cross-sectional area (CSA) ranged from 0.58 to 0.92. Overall, Intra rater ICC values (0.59-0.99) were marginally higher than Inter rater values (0.45-0.99) across all tendon sites. Percentage co-efficient of variation (CV%) for tendon thickness and CSA ranged from 0 to 35% across all tendons. Percentage standard error of the mean SEM% values for tendon thickness ranged from 3.33% to 7.39%.
Conclusions:
The findings of this review suggest diagnostic US measures of tendon size are reliable, both in terms of relative and absolute reliability. However, the findings must be considered in light of the presence of tendon abnormalities in a large percentage of asymptomatic populations.
... These images were reformatted into a regular 3D grid using a volume reconstruction algorithm. 8,9 A 3D surface model of the blood vessel was then generated from traced borders of the vessel lumen. 10,11 Calculation of Blood Flow Velocity Computational fluid dynamics modeling was applied to the carotid artery to calculate 4-dimensional (4D) flow velocity fields (spatially 3D and temporally resolved) inside the vascular lumen. ...
Objective:
Duplex ultrasound scanning with B-mode imaging and both color Doppler and Doppler spectral waveforms is relied upon for diagnosis of vascular pathology and selection of patients for further evaluation and treatment. In most duplex ultrasound applications, classification of disease severity is based primarily on alterations in blood flow velocities, particularly the peak systolic velocity (PSV) obtained from Doppler spectral waveforms. We developed a duplex ultrasound simulator for training and assessment of scanning skills.
Methods:
Duplex ultrasound cases were prepared from 2-dimensional (2D) images of normal and stenotic carotid arteries by reconstructing the common carotid, internal carotid, and external carotid arteries in 3 dimensions and computationally simulating blood flow velocity fields within the lumen. The simulator displays a 2D B-mode image corresponding to transducer position on a mannequin, overlaid by color coding of velocity data. A spectral waveform is generated according to examiner-defined settings (depth and size of the Doppler sample volume, beam steering, Doppler beam angle, and pulse repetition frequency or scale). The accuracy of the simulator was assessed by comparing the PSV measured from the spectral waveforms with the true PSV which was derived from the computational flow model based on the size and location of the sample volume within the artery.
Results:
Three expert examiners made a total of 36 carotid artery PSV measurements based on the simulated cases. The PSV measured by the examiners deviated from true PSV by 8% ± 5% (N = 36). The deviation in PSV did not differ significantly between artery segments, normal and stenotic arteries, or examiners.
Conclusion:
To our knowledge, this is the first simulation of duplex ultrasound that can create and display real-time color Doppler images and Doppler spectral waveforms. The results demonstrate that an examiner can measure PSV from the spectral waveforms using the settings on the simulator with a mean absolute error in the velocity measurement of less than 10%. With the addition of cases with a range of pathologies, this duplex ultrasound simulator will be a useful tool for training health-care providers in vascular ultrasound applications and for assessing their skills in an objective and quantitative manner.
... Over the last three decades, there have been numerous studies on spatial compounding for the improvement of medical ultrasound data. There have been reports on the effectiveness of real-time spatial compounding on numerous anatomical structures such as the breast (Entrekin et al., 1999;Huber et al., 2002;Seo et al., 2002), the thyroid gland (Shapiro et al., 2001), the abdomen and pelvis (Oktar et al., 2003;Kim et al., 2004), the rotator cuff (Leotta & Martin, 2000b), the vascular (Kofoed et al., 2001) and the musculoskeletal system (Lin et al., 2002). There have also been a number of studies on novel 2D (Hernandez et al., 1996;Jespersen et al., 1998Jespersen et al., , 2000Behar et al., 2003;Bashford & Morse, 2006) as well as 3D (Moskalik et al., 1995;Rohling et al., 1997;Krucker et al., 2000;Leotta & Martin, 2000a;Liu et al., 2004) spatial alignment and compounding methods. ...
Cardiovascular diseases (CVDs) constitute a leading cause of death, including premature
death, in the developed world. The early diagnosis and treatment of CVDs is therefore of
great importance. Modern imaging modalities enable the quantification and analysis of the
cardiovascular system and provide researchers and clinicians with valuable tools for the
diagnosis and treatment of CVDs. In particular, echocardiography offers a number of
advantages, compared to other imaging modalities, making it a prevalent tool for assessing
cardiac morphology and function. However, cardiac ultrasound images can suffer from a
range of artifacts reducing their image quality and diagnostic value. As a result, there is great
interest in the development of processing techniques that address such limitations.
This thesis introduces and quantitatively evaluates four methods that enhance clinical cardiac
ultrasound data by utilising information which until now has been predominantly
disregarded. All methods introduced in this thesis utilise multiple partially uncorrelated
instances of a cardiac cycle in order to acquire the information required to suppress or
enhance certain image features. No filtering out of information is performed at any stage
throughout the processing. This constitutes the main differentiation to previous data
enhancement approaches which tend to filter out information based on some static or
adaptive selection criteria.
The first two image enhancement methods utilise spatial averaging of partially uncorrelated
data acquired through a single acoustic window. More precisely, Temporal Compounding
enhances cardiac ultrasound data by averaging partially uncorrelated instances of the imaged
structure acquired over a number of consecutive cardiac cycles. An extension to the notion of
spatial compounding of cardiac ultrasound data is 3D-to-2D Compounding, which presents a
novel image enhancement method by acquiring and compounding spatially adjacent (along
the elevation plane), partially uncorrelated, 2D slices of the heart extracted as a thin angular
sub-sector of a volumetric pyramid scan. Data enhancement introduced by both approaches
includes the substantial suppression of tissue speckle and cavity noise. Furthermore, by
averaging decorrelated instances of the same cardiac structure, both compounding methods
can enhance tissue structures, which are masked out by high levels of noise and shadowing,
increasing their corresponding tissue/cavity detectability.
The third novel data enhancement approach, referred as Dynamic Histogram Based Intensity
Mapping (DHBIM), investigates the temporal variations within image histograms of
consecutive frames in order to (i) identify any unutilised/underutilised intensity levels and
(ii) derive the tissue/cavity intensity threshold within the processed frame sequence.
Piecewise intensity mapping is then used to enhance cardiac ultrasound data. DHBIM
introduces cavity noise suppression, enhancement of tissue speckle information as well as
considerable increase in tissue/cavity contrast and detectability.
A data acquisition and analysis protocol for integrating the dynamic intensity mapping along
with spatial compounding methods is also investigated. The linear integration of DHBIM and
Temporal Compounding forms the fourth and final implemented method, which is also
quantitatively assessed. By taking advantage of the benefits and compensating for the
limitations of each individual method, the integrated method suppresses cavity noise and
tissue speckle while enhancing tissue/cavity contrast as well as the delineation of cardiac
tissue boundaries even when heavily corrupted by cardiac ultrasound artifacts.
Finally, a novel protocol for the quantitative assessment of the effect of each data
enhancement method on image quality and diagnostic value is employed. This enables the
quantitative evaluation of each method as well as the comparison between individual
methods using clinical data from 32 patients. Image quality is assessed using a range of
quantitative measures such as signal-to-noise ratio, tissue/cavity contrast and detectability
index. Diagnostic value is assessed through variations in the repeatability level of routine
clinical measurements performed on patient cardiac ultrasound scans by two experienced
echocardiographers. Commonly used clinical measures such as the wall thickness of the
Interventricular Septum (IVS) and the Left Ventricle Posterior Wall (LVPW) as well as the
cavity diameter of the Left Ventricle (LVID) and Left Atrium (LAD) are employed for
assessing diagnostic value.
... Bereits in anderen Studien zeigte sich, dass die 3D-Darstellung der Rotatorenmaschette eine hohe Übereinstimmung mit der 2D-Darstellung hat [110]. Wallny ...
Zur Diagnostik von Rupturen der Rotatorenmanschette wird häufig die im Vergleich zur Sonografie deutlich kostenintensivere Magnetresonanztomografie durchgeführt. Ein Grund hierfür ist, dass es zum Teil schwierig ist, standardisierte statische Sonografie-Bilder zu gewinnen, was die reproduzierbare, untersucherunabhängige diagnostische Information verringert. Ziel des ersten Teils der Arbeit war es einerseits, zu analysieren, ob mit der 3D-Sonografie diese Probleme verringert werden könnten und andererseits die Sensitivität mit dem 2D-Ultraschall zur Diagnostik von Komplett- und Partialrupturen zu vergleichen. Bei der Untersuchung von 114 Patienten konnten mit dem 3D-Ultraschall Rupturen der Rotatorenmanschette gut dargestellt werden. Der Vergleich zwischen 2D- und 3D-Ultraschall ergab keinen statistisch signifikanten Unterschied zwischen beiden Verfahren für die Diagnostik von Komplett- und Partialrupturen. Ein Vorteil war die Möglichkeit der untersucherunabhängigen simultanen Auswertung von drei standardisierten Schnittebenen zu einem späteren Zeitpunkt. Bei der Verwendung biodegradierbarer Anker zur Fixierung von Weichteilen können ossäre Reaktionen auftreten. Ziel war es, die frühen Reaktionen des umgebenden Gewebes auf einen Poly-(L-co-D/L-Lactid) 70/30 Anker im Vergleich zu einem Titananker im Schafsknochen zu analysieren. Innerhalb von 20 Wochen nach Implantation zeigte sich keinerlei Verlust von Knochensubstanz im Bereich des distalen Schafsfemur bei Ankern aus Titan oder aus Polylactid. Vielmehr zeigte sich eine ausgeprägte Neuformation von spongiösem Knochen in die Implantathohlräume vor allem für das biodegradierbare Material. Daher sollten neben materialbedingten Ursachen auch biomechanische Ursachen wie zyklische Belastungen für mögliche Osteolysen in Betracht gezogen werden. Die arthroskopische subacromiale Dekompression (ASD) ist ein häufig durchgeführtes Verfahren zur Therapie von Subachromialsyndromen. Es sollten die eigenen Ergebnisse seit 1993 unter Berücksichtigung von Nebendiagnosen sowie die Möglichkeit, verschiedene Scores und VAS auch telefonisch erheben zu können, analysiert werden. Die Untersuchung von 422 Schultern zwischen 1,5 und 9,5 Jahren (durchschnittlich 4,8 Jahre) nach der Operation zeigte, dass die ASD mit überwiegend guten und sehr guten subjektiven und objektiven Resultaten (ca. 75%) ein zuverlässiges operatives Verfahren ist. Im Gegensatz zu einem laufenden Rentenverfahren hatten Rupturen der Rotatorenmanschette zum Zeitpunkt der Operation keinen negativen Einfluss auf das Operationsergebnis. Bei Nichtbeachtung der Pathologie des superioren Labrums und bei Rezidivoperation kam es zu einem erhöhten Anteil an Therapieversagern. Die telefonische Erhebung verschiedener Schulter-Scores (ausgenommen Constant-Score) und der VAS lieferte valide Resultate, die eine klinische Untersuchung entbehrlich machen und insbesondere bei Langzeitstudien eine wesentlich höhere Nachuntersuchungsrate ermöglichen. Das Konzept der winkelstabilen Osteosynthese ermöglicht eine weichteilschonende, minimal-invasive Frakturstabilisierung. Um eine sichere Verankerung von winkelstabilen Schrauben zu erreichen, ist eine korrekte Positionierung der Schraube in der Platte erforderlich. In biomechanischen Testungen konnte gezeigt werden, dass bei einer geringen Abweichung des Insertionswinkels winkelstabiler Schrauben von bis zu 5° vom optimalen Winkel immer noch eine hohe Stabilität der Schrauben-/Plattenverbindung gewährleistet war. Ab einem Winkel von über 5° kam es zu einer signifikanten Abnahme der Festigkeit dieser Verbindung. Um eine optimale Festigkeit der Verbindung Schraube/Platte zu erreichen und das Risiko der Schraubenlockerung zu minimieren, ist die konsequente Benutzung eines Zielgerätes zu empfehlen. Die klinische Nachuntersuchung von 53 Patienten mit winkelstabiler Osteosynthese bei proximaler Humerusfraktur zeigte eine mit der Literatur vergleichbare Komplikationsrate bei verringertem sekundären Dislokationsrisiko. Es zeigte sich aber auch die Problematik dieser Fakturen mit langer Nachbehandlungsdauer und dem Risiko einer Humeruskopfnekrose im Verlauf. Winkelstabile Implantate ermöglichten eine sichere Stabilisierung von proximalen Humerusfrakturen, konnten jedoch eine insuffiziente Anwendung - wie eine fehlerhafte Verankerung der Kopfverriegelungsschrauben - nicht kompensieren. Erhöht war das Risiko einer Schraubenperforation durch die Sinterung des Kopfes auf das rigide Implantat.
... The reference lists of the included articles were searched for any additional papers, with no additional papers identified. Six articles were excluded (AC Gellhorn, 2013;Arend et al., 2014;Leotta and Martin, 2000;Malanga et al., 2012;Ryan et al., 2013;Shen and Li, 2012) after screening the full text of the identified articles for reasons outlined in figure 2.The final number of articles included in this review was 22. Study ...
... The reference lists of the included articles were searched for any additional papers, with no additional papers identified. Six articles were excluded (AC Gellhorn, 2013;Arend et al., 2014;Leotta and Martin, 2000;Malanga et al., 2012;Ryan et al., 2013;Shen and Li, 2012) after screening the full text of the identified articles for reasons outlined in figure 2.The final number of articles included in this review was 22. Study ...
Pathological tendons are known to increase their AP diameter. Ultrasound is an important complementary technique to MRI for assessment of musculoskeletal disorders. Although systematic reviews have confirmed its reliability for the measurement of muscle thickness, no such reviews exist to examine the reliability of US measures of tendon dimensions.
To systematically review the literature on the reliability of Real-time ultrasound to assess tendon dimensions including thickness and cross sectional area in human limbs.
A comprehensive review of electronic databases was performed by two reviewers using agreed range of keywords. Randomised clinical trials which investigated inter or intra rater reliability of real time ultrasound was included in this review. The Quality Appraisal of Reliability Studies (QAREL) checklist was used to assess risk of bias.
Included studies performed ultrasound analysis in a range of clinical settings.
698 Symptomatic and asymptomatic participants, mean age range: 17.5-73 years.
Tendon thickness of a range of upper and lower limb tendons was assessed using real time ultrasound in both transverse and longitudinal planes by physiotherapists, sonographers and other unspecified investigators.
Inter and Intra rater reliability of tendon thickness measures using estimates of both reliability and precision using intraclass correlation coefficients (ICC's) and coefficients of variation (CVs), coefficient of variation (CV%) limits of agreement (LOA), pearsons correlation coefficient (r2) and 95% confidence intervals (95% CI).
Assessment of the risks of bias indicated 15/16 chosen studies was of high quality. ICC values for inter and intra rater reliability ranged from (0.55-0.99), LOA ranged from (0.35-3.50 mm), r2 ranged from (0.43-0.92), 95% CI ranged from (0.43-0.98), CV% ranged from (0-14.44%).
The use of real time ultrasound method for assessing upper and lower limb tendon thickness has moderate-to-good level reliability. The findings of which may have important implications for management of tendon disorders.
... 1,2,5,6 La historia clínica y examen físico pueden ser suficientes para tener un diagnóstico presuntivo, pero para precisar el tipo de lesión es necesario realizar un estudio complementario de imágenes. 7,11,12,18,19 Existen diversos métodos imagenólogicos para apoyar los diagnósticos de patología del MR. En nuestro medio, la ecografía de alta resolución es la primera elección, debido a las ventajas de ser un examen de rápida realización, no invasivo y de bajo costo. ...
To analyze the preoperative shoulder ultrasound (US) findings in patients with a diagnosis of rotator cuff (RC) tear and correlate them with the arthroscopic findings.
Retrospective analysis of a consecutive series of patients with a diagnosis of RC pathology in whom US was performed and who underwent surgery (shoulder arthroscopy). The US/arthroscopic findings were correlated with Fisher's and chi2 tests.
The total number of patients was 53. We identified US/arthroscopic correlation in 22/34 cases for the total tears (64.7%) and in 7/19 cases for the partial tears (36.8%) (p = 0.048). Overall correlation (total and partial tears) was seen in 29/53 patients (54.7%). Of the 24 patients without correlation, 11 (45.8%) had ultrasound reports of tendinitis; 75% of the cases in this group had findings of partial supraspinous tear during arthroscopy (p = 0.006).
US shows an appropriate correlation with the diagnosis of RC total tear confirmed with arthroscopy, and the correlation is significantly lower for partial tears. In cases of an ultrasound-diagnosed lesion, such as tendinitis, most cases showed a partial tear during arthroscopy.
... Different combinations of the diverse signals were also investigated for compounding purpose [Jespersen et al 2000]. Spatial compounding has also been utilized recently in three-dimensional imaging [Krucker et al 2000, Leotta and Martin 2000]. So far we have discussed the application of spatial diversity and compounding to enhance the visibility of an object/target by scanning the object from different spatial locations and then combining the diverse signals. ...
Ultrasonic tissue characterization aims at improving the ability of ultrasound to classify benign and malignant masses. The akagami distribution was recently proposed to model the statistics of the envelope of the backscattered echo from tissue. Its parameters demonstrated an ability to discriminate benign and malignant masses in breast tissue. However, there is a need to improve the performance of the parameters to reach clinically acceptable standards and also to eliminate any influence of variation in operator gain settings during scanning, time-gain compensation settings, location of the mass, depth and frequency dependent attenuation characteristics and size of the range cell on the parameters while performing the classification. In this research, diversity techniques have been investigated to achieve these goals. Analytical results explaining the improvement in the ability of the parameters to separate different scattering conditions have been derived and tested through computer simulation and experiments on tissue-mimicking phantoms. The technique is then applied to classify in vivo breast masses as benign or malignant. Frequency diversity and compounding are specifically applied to normalize both the parameters of the Nakagami distribution making them insensitive to any of the variations described above. A combination of normalized Nakagami parameters at the site from spatially diverse images of a mass, similar to spatial compounding, is performed to improve the ability to discriminate benign and malignant masses along with a theoretical explanation of why such a combination is likely to improve the classification performance. ROC analysis is undertaken to evaluate the performance of the parameters before and after diversity and compounding. Additional parameters conveying information about the sharpness of the boundary and scattering characteristics at the site are combined with the normalized Nakagami parameter after spatial compounding, improving the area under the ROC curve z A to 0.87 and reaching a sensitivity and specificity of 95% and 70% respectively. The performance of this parameter-based approach requiring minimal clinical intervention exceeded that of the radiologist encouraging its application for automated classification and also as an adjunct to x-ray mammography in reducing unnecessary biopsies.
... In contrast, 2-D arrays analogous to 1-D linear arrays with 128 to 256 elements would need 128 2 to 256 2 , or 16,384 to 65,536 elements to scan a rectilinear, boxshaped volume. A 3-D system having this type of 2-D linear array could improve guidance of breast biopsies, assessment of disease in the carotid artery, and evaluation of musculoskeletal injuries [5][6][7]. Currently, it has not been demonstrated whether the same technology used to develop fully sampled 2-D phased arrays with less than 5,000 elements can be realistically applied to 2-D transducer arrays with significantly larger element counts. Alternative solutions for 3-D imaging requiring as many as 65,000 2-D array elements should be explored. ...
Very large element counts (16,000-65,000) are required for 2-D arrays for 3-D rectilinear imaging. The difficulties in fabricating and interconnecting 2-D arrays with a large number of elements (>5,000) have limited the development of suitable transducers for 3-D rectilinear imaging. In this paper, we propose an alternative solution to this problem by using a dual-layer transducer array design. This design consists of 2 perpendicular 1-D arrays for clinical 3-D imaging of targets near the transducer. These targets include the breast, carotid artery, and musculoskeletal system. This transducer design reduces the fabrication complexity and the channel count, making 3-D rectilinear imaging more realizable. With this design, an effective N x N 2-D array can be developed using only N transmitters and N receivers. This benefit becomes very significant when N becomes greater than 128, for example. To demonstrate feasibility, we constructed a 4 x 4 cm prototype dual-layer array. The transmit array uses diced PZT-5H elements, and the receive array is a single sheet of undiced P[VDF-TrFE] copolymer. The receive elements are defined by the copper traces on the flexible interconnect circuit. The measured -6 dB fractional bandwidth was 80% with a center frequency of 4.8 MHz. At 5 MHz, the nearest neighbor crosstalk of the PZT array and PVDF array was -30.4 +/- 3.1 dB and -28.8 +/- 3.7 dB, respectively. This dual-layer transducer was interfaced with an Ultrasonix Sonix RP system, and a synthetic aperture 3-D data set was acquired. We then performed offline 3-D beamforming to obtain volumes of nylon wire targets. The theoretical lateral beamwidth was 0.52 mm compared with measured beamwidths of 0.65 mm and 0.67 mm in azimuth and elevation, respectively. Then, 3-D images of an 8 mm diameter anechoic cyst phantom were also acquired.
... Spatial compounding of ultrasound images allows more complete bone visualization when different view angles are used, and real-time spatial compounding as well as extended field of view ultrasound have been applied to the shoulder, knee, and Achilles tendon. Freehand ultrasound imaging with spatial compounding, using a magnetic tracker, has been used as an alternative to MRI to measure rotator cuff thickness [47]. ...
The biomechanical interaction between the residual limb and the prosthetic socket determines the quality of fit of the socket in lower limb prosthetics. An understanding of this interaction and the development of quantitative measures to predict the quality of fit of the socket are important for optimal socket design. Finite-element modeling is used widely for biomechanical modeling of the limb/socket interaction and requires information on the internal and external geometry of the residual limb. Volumetric imaging methods such as X-ray computed tomography, magnetic resonance imaging, and ultrasound have been used to obtain residual limb shape information. Of these modalities, ultrasound has been introduced most recently and its development for visualization in prosthetics is the least mature. This paper reviews ultrasound image acquisition and processing methods as they have been applied in lower limb prosthetics.
Abscesses are walled-off collections of infected fluids that often develop as complications in the setting of surgery and trauma. Treatment is usually limited to percutaneous catheterization with a course of antibiotics. As an alternative to current treatment strategies, a histotripsy approach was developed and tested in a novel porcine animal model. The goal of this article is to use advanced ultrasound imaging modes to extract sonographic features associated with the progression of abscess development in a porcine model. Intramuscular or subcutaneous injections of a bi-microbial bacteria mixture plus dextran particles as an irritant led to identifiable abscesses over a 2 to 3 wk period. Selected abscesses were imaged at least weekly with B-mode, 3-D B-mode, shear-wave elastography and plane-wave Doppler imaging. Mature abscesses were characterized by a well-defined core of varying echogenicity surrounded by a hypoechoic capsule that was highly vascularized on Doppler imaging. 3-D imaging demonstrated the natural history of abscess morphology, with the abscess becoming less complex in shape and increasing in volume. Furthermore, shear-wave elastography demonstrated variations in stiffness as phlegmon becomes abscess and then liquefies, over time. These ultrasound features potentially provide biomarkers to aid in selection of treatment strategies for abscesses.
Infected abscesses are walled-off collections of pus and bacteria. They are a common sequela of complications in the setting of surgery, trauma, systemic infections and other disease states. Current treatment is typically limited to antibiotics with long-term catheter drainage, or surgical washout when inaccessible to percutaneous drainage or unresponsive to initial care efforts. Antibiotic resistance is also a growing concern. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. In particular, short pulses of focused ultrasound (i.e., histotripsy) generate mechanical damage through localized cavitation, representing a potential new paradigm for treating abscesses non-invasively, without the need for long-term catheterization and antibiotics. In this pilot study, boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses developed in a novel porcine model. Ultrasound imaging was used to evaluate abscess maturity for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. Cavitation histotripsy was more successful in reducing the bacterial load while having a smaller treatment volume compared with boiling histotripsy. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.
2-D spatial compounding has long been investigated to reduce speckle in ultrasound images. To further reduce speckle, several 3-D spatial compounding studies using 1-D and 1.5 D arrays with mechanical translation and position tracking have been reported. However, the fixed elevational focus and mechanical translation can degrade image quality in elevation. Using 2-D arrays, a better elevational resolution can be achieved with electronic focusing. Furthermore, 2-D arrays can generate greater number of independent images than 1-D arrays and the need for mechanical scanning is eliminated.
In this paper, we present our 3-D spatial compounding images of two gel-based contrast phantoms and one resolution phantom. These images were acquired using a prototype 4 cm × 4 cm ultrasonic row-column prototype 2-D array operating at 5 MHz. Compounding nine decorrelated volumes showed a speckle signal-to-noise ratio (SNR) improvement of 2.68. The average improvement of the lesion contrast-to-noise ratio (CNR) was 2.45. However, using a smaller aperture to generate these volumes worsened the lateral resolution as predicted by theory.
We developed a duplex ultrasound simulator for training and assessment of scanning skills. We used the simulator to test examiner performance in the measurement of flow velocities in dialysis access fistulas. Test cases were created from 3-D ultrasound scans of two dialysis access fistulas by reconstructing 3-D blood vessel models and simulating blood flow velocity fields within the lumens. The simulator displays a 2-D B-mode or color Doppler image corresponding to transducer position on a mannequin; a spectral waveform is generated according to Doppler sample volume location and system settings. Examiner performance was assessed by comparing the measured peak systolic velocity (PSV) with the true PSV provided by the computational flow model. The PSV measured by four expert examiners deviated from the true value by 7.8 ± 6.1%. The results indicate the ability of the simulator to objectively assess an examiner's measurement accuracy in complex vascular targets.
Plaque in the carotid artery is typically formed at the bifurcation in the neck, but in contrast to most other vessels in the body, rather than the reduction in lumen diameter it is risk of embolization of small blood vessels in the brain, i.e. the risk of stroke, that is the primary cause for concem. The carotid artery can be visualized with extra-vascular ultrasound and the main parameters of this scanning situation is considered in this chapter, including aspects of the degradation due to the medium between transducer and plaque. The ultrasound images are affected by variations in gray scale value due to speckle and angle-dependence and due to intervening anisotropic tissue. Spatial compound imaging is introduced and it is shown with in vitro and in vivo examples how the speckle can be reduced this way. Error sources and potential problems are discussed. For the in vitro investigations, it is shown how the tissue types in the plaque can be determined by scanning the plaque casted into an agar block and subsequently cutting this block at given calibration marker locations. Both anatomical and histological images can then be obtained at the same scan plane as that of the ultrasound image. Finally, future techniques for classification ofplaque tissue with extra-vascular ultrasound is discussed.
Objective
The purpose of this study was to compare the effects of manual therapy with exercise to kinesiotaping with exercise for patients with subacromial impingement syndrome.
Methods
Randomized clinical before and after trial was used. Fifty-four patients diagnosed as having subacromial impingement syndrome who were referred for outpatient treatment were included. Eligible patients (between 30 and 60 years old, with unilateral shoulder pain) were randomly allocated to 2 study groups: kinesiotaping with exercise (n = 28) or manual therapy with exercise (n = 26). In addition, patients were advised to use cold packs 5 times per day to control for pain. Visual analog scale for pain, Disability of Arm and Shoulder Questionnaire for function, and diagnostic ultrasound assessment for supraspinatus tendon thickness were used as main outcome measures. Assessments were applied at the baseline and after completing 6 weeks of related interventions.
Results
At the baseline, there was no difference between the 2 group characteristics (P > .05). There were significant differences in both groups before and after treatment in terms of pain decrease and improvement of Disability of Arm and Shoulder Questionnaire scores (P < .05). No difference was observed on ultrasound for tendon thickness after treatment in both groups (P > .05). The only difference between the groups was at night pain, resulting in favor of the kinesiotaping with exercise group (P < .05).
Conclusion
For the group of subjects studied, no differences were found between kinesiotaping with exercise and manual therapy with exercise. Both treatments may have similar results in reducing pain and disability in subacromial impingement in 6 weeks.
The shoulder is among the most difficult joints to image well using ultrasound, likely contributing to the wide range of reported success of ultrasound in diagnosing rotator cuff tears. Using well defined techniques and criteria, recent studies have demonstrated very favorable results in detecting rotator cuff pathology using ultrasound. Special attention must be given to the potential pitfalls due to tendon curvature and the complex anatomy of the rotator cuff, as well as to using appropriate equipment. Current literature demonstrates a sensitivity of 91 to 95% and approximately 90% specificity and accuracy in the assessment of both partial‐ and full‐thickness tears using ultrasound.
Technical advances in ultrasound imaging are expected to further expand the role of ultrasound in the evaluation of rotator cuff pathology by offering improved image quality and reducing its inherent operator dependence. These include tissue harmonic imaging, extended field‐of‐view imaging, and 3‐dimensional imaging. The real‐time nature of ultrasound permits dynamic assessment of shoulder stability, tendon subluxations, as well as allowing accentuation of cuff tears. This review will covers the sonographic anatomy, scanning techniques, and pathology of the rotator cuff and long head of biceps tendons, emphasizing recent advances in ultrasound technology as these apply to the rotator cuff. Examples of the sonographic appearances following cuff repair and in the presence of a shoulder replacement will also be included.
This paper discusses and researches the influence of shoulder movement direction on different shoulder activities movements. Then present recommend of therapy treatment is based on findings. This research is divided into two parts. First, to find out effective shoulder movement direction that may be more effective therapy, emphasized on influence of range of shoulder motion. Second, indicate and estimate movement direction when and how shoulder muscles are used. Therefore, those findings in this paper can help us to avoid further hurts and can improve effect of therapy treatment. The experiment includes 5 groups, 50 normal people with healthy shoulders, are observed, aging from 40 to 60. There are 5 different kinds of shoulder movement direction, including shoulder abduction, forward flexion, backward extension, shoulder external rotation, and shoulder internal rotation. Based on individual group, patients would do one assigned shoulder movement direction, 3 to 5 minutes a time, twice a day, and total 4 weeks. Results indicate that there is interaction of treatment between shoulder abduction and forward flexion. In other words, when shoulder abduction is effective, range of motion of shoulder abduction increases, as well as range of motion of forward flexion. Doing flexion also increases range of motion of forward flexion and shoulder abduction. On the other hand, there is also interactive rotation and shoulder internal rotation. The results of EMG indicate that not only fewer muscles are used, but also smaller powers are released, because observed estimated IEMG become smaller. Therefore, muscles become stronger.
The shoulder is one of the most common applications of musculoskeletal US due to the high incidence of rotator cuff disorders
related to increasing aging and sporting activities. Many papers dealing with the US scanning technique of the rotator cuff
tendons have already been published in the radiological, rheumatologic and orthopaedic literature and US is now widely recognized
as an accurate means to evaluate rotator cuff disease (Ptasznik 2001; Bouffard et al. 2000; Brasseur et al. 2000; Thain and Adler 1999; Bretzke et al. 1985; Collins et al. 1987; Crass et al. 1985; Hall 1986; Middleton et al. 1984; Middleton et al. 1986b; Mack et al. 1988a; Middleton 1989; Seibold et al. 1999; Teefey et al. 2000; Naredo et al. 2002). With appropriate equipment and skilled hands, this technique provides assessment of rotator cuff pathology with high sensitivity
and specificity in the diagnosis of both partial and fullthickness tears with some specific advantages over MR imaging, such
as higher resolution capabilities and the ability to examine tissues in both static and dynamic states and with the patient
in different positions.
Hintergrund Ziel der hier durchgeführten prospektiven Studie ist die Feststellung der diagnostischen Sicherheit der dreidimensionalen (3D-)Sonographie bei Meniskusläsionen. Material und Methoden Es wurden 34 Sonographien (11,7-MHz-Linearschallkopf) unter Einsatz der 3D-Rekonstruktion klinisch vermuteter Meniskusläsionen durchgeführt. Im Vorfeld erfolgte die Anfertigung einer MRT, deren Bilder und Befund dem Untersucher nicht bekannt war. Der vom anfertigenden Radiologen erstellte Befund wurde zur späteren Auswertung herangezogen. Die Situation am Meniskus wurde arthroskopisch festgestellt und als Referenz herangezogen. Ergebnisse Arthroskopisch fanden sich 10 Außen- und 47 Innenmeniskusläsionen unterschiedlicher Lokalisationen. Die Sensitivität (0,5–0,78) und Spezifität (0,75–0,95) der beiden Untersuchungsverfahren war insgesamt vergleichbar. Schlussfolgerung Die Ultraschalltechnik inklusive 3D-Rekonstruktion und hoch auflösendem Schallkopf in der Hand des Erfahrenen erreicht eine ähnlich gute Diagnosesicherheit wie die MRT in einer allgemein radiologischen Untersuchung.
The present study aimed to quantify the thickness of articular cartilage (Tc) in vitro using both conventional and real-time spatial compound B-mode ultrasonography (US) with a clinically used transducer and to evaluate the accuracy of measurement by comparing the results with values obtained microscopically. Femoral condyle samples were obtained from a 6-month-old pig and a 3-year-old pig. B-mode US images with conventional imaging and real-time spatial compound imaging (RTSCI) of osteochondral blocks were acquired. Tc determined using US (Tc-US) was measured from line data parallel to US beam direction acquired from B-mode images with an objective method for determining cartilage surface and bone-cartilage interfaces at the peak brightness values. Tc was also determined under microscopy (Tc-optical) using the corresponding points from US measurement. Tc-US was compared with Tc-optical to assess accuracy. Tc-US correlated significantly with Tc in both conventional imaging and RTSCI (r = 0.961, 0.976, respectively). Bland-Altman plots showed mean differences between Tc-optical and Tc-US were -0.0073 mm and 0.0139 mm with standard deviations of 0.171 mm and 0.131 mm for conventional imaging and RTSCI, respectively. Our results show that Tc-US measurement using B-mode US allows accurate measurement of Tc. Considering correlation coefficients between Tc-US and Tc-optical, RTSCI US may offer higher accuracy for measuring Tc than conventional methods when an objective tissue border determination algorithm is used, even though both showed good accuracy in our study.
2-D spatial compounding has long been investigated to reduce speckle in ultrasound images. To further reduce speckle, several 3-D spatial compounding studies using 1-D and 1.5 D arrays with mechanical translation and position tracking have been reported. However, the fixed elevational focus and mechanical translation can degrade image quality in elevation. Using 2-D arrays, a better elevational resolution can be achieved with electronic focusing. Furthermore, 2-D arrays can generate greater number of independent images than 1-D arrays and the need for mechanical scanning is eliminated.
In this paper, we present our 3-D spatial compounding images of two gel-based contrast phantoms and one resolution phantom. These images were acquired using a prototype 4 cm × 4 cm ultrasonic row-column prototype 2-D array operating at 5 MHz. Compounding nine decorrelated volumes showed a speckle signal-to-noise ratio (SNR) improvement of 2.68. The average improvement of the lesion contrast-to-noise ratio (CNR) was 2.45. However, using a smaller aperture to generate these volumes worsened the lateral resolution as predicted by theory.
The objective of the study was to compare the diagnostic reliability of 3D US with MR arthrography in diagnosing supraspinatus tendon tears, with arthroscopic findings used as the standard.
In a prospective study 50 patients who later underwent arthroscopic surgery of the rotator cuff were examined pre-operatively by 3D US with MR arthrography. The presence or absence of a full- or partial-thickness supraspinatus tendon tear and the tear size as demonstrated by each imaging and arthroscopy was recorded. The tear size was divided into three grades: small (<1 cm), medium (1-3 cm), and large (>3 cm).
The arthroscopic diagnosis was a full-thickness tear in 40 patients, partial-thickness tears in 5, and intact supraspinatus tendon in 5. 3D US correctly diagnosed 35 out of 40 full-thickness tears and MR arthrography 39 out of 40 full-thickness tears. Regarding partial-thickness tears, 3D US underestimated 2 cases as no tear and overestimated 1 case as a full-thickness tear. MR arthrography underestimated 1 case as a partial-thickness tear and overestimated 2 cases as full-thickness and partial-thickness tears respectively. 3D US and MR arthrography yield a sensitivity for full-thickness tears of 87.5% and 97.5% with specificity of 90.0% and 90.0%. Based on the grading system, 3D US measurements correctly predicted the tear size of 23 (65.7%) of the 35 full-thickness tears and MR arthrography 30 (75.0%) of the 39 full-thickness tears.
Three-dimensional ultrasound seems to be a promising imaging modality comparable to MR arthrography for the assessment of the supraspinatus tendon tears.
It is possible to evaluate the size of rotator cuff tears by ultrasonography (US) or magnetic resonance imaging. However, there are only a few reports on the imaging assessment of the configuration of cuff tears, which could provide important preoperative information that assists performing an optimal anatomical repair. The purpose of this study was to determine quantitatively the reproducibility of three-dimensional US in the assessment of rotator cuff tear configuration.
Ten embalmed cadaveric shoulders with rotator cuff tears were examined. After resecting the proximal humerus with the rotator cuff, we put it in water and scanned it using high-resolution US with a three-dimensional linear probe. Actual tear lengths and widths were compared with sonographic measurements (Pearson correlation coefficient). By superimposing the real photographic image on the reconstructed three-dimensional image, we calculated the concordance rate (ratio of the concordance area to the tear area).
The actual tear length (16.6 +/- 7.1 mm; mean +/- SD) and width (8.4 +/- 4.4 mm) were correlated with the tear length (16.4 +/- 7.5 mm) and width (8.2 +/- 4.4 mm) measured from reconstructed three-dimensional ultrasonograms (r = 0.998 and 0.994, respectively). The mean concordance rate was 91.4%, indicating that almost exactly the same configuration was reconstructed by US.
Three-dimensional US is useful for evaluating the configuration of rotator cuff tears. This is the first report to quantify the similarity between the configuration evaluated by US and the actual configuration. Using this method, we can visualize the configuration of rotator cuff tears preoperatively, facilitating optimal repair design.
The aim of this study was to visualise the fetal heart in dynamic three dimensions (4-D) during an ultrasound (US) scan (online), rather than after (offline). With special pairing and sequential setting to minimise interference between two scanners, umbilical arterial Doppler waveforms (UADWs) from one scanner were used as an online motion gating source to trigger simultaneous 3-D cardiac structural data acquisition by another. Of 25 data sets from 10 fetuses, 18 were acquired in 15 to 30 s per set with ≥ 50% Doppler waveforms efficiently converted to triggering signals. Of 15 valid 4-D data sets, 10 were reconstructed in 2 to 20 min, compared to over 2 h previously reported (mainly for offline gating). Fine structures (including chordae tendinae and trabecular muscles) were depicted in six sets. The main problems in degrading 4-D images were extensive shadowing (6) from bony structures during rigid mechanical scanning, and random motion artefacts (6) from prolonged setting-up time with a complex combination of several systems. Integration of these systems is, therefore, recommended. (E-mail:[email protected]
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Image compounding reduces the artifacts inherent in ultrasound imaging, but accurate matching of images for compounding depends on their accurate placement in the compound image plane. A method is presented to reduce displacement errors during compounding of ultrasound B-scans of a normal human shank. A genetic algorithm was used to place matching B-scans in the compound image. The method was tested on a phantom and was shown to reduce, but not eliminate, mismatches due to the displacement of B-scans from their original position in the compound image plane. The results can be extended to applications in lower-limb prosthetics, where ultrasound imaging can be used to visualise the internal geometry of amputees' residual limbs.
Classification of masses in ultrasonic B-mode images of the breast tissue using "normalized" parameters of the Nakagami distribution was recently investigated. The technique, however, did not yield performances that were comparable to those of an experienced radiologist, and utilized only a single image for tissue characterization. Because radiologists commonly use two to four images of a mass for characterization, a similar procedure is developed here. A simple summation of the normalized Nakagami parameters from two different images of a mass is utilized for classification as benign or malignant. The performance of the normalized Nakagami parameters before and after the summation has been carried out through a receiver operating characteristic (ROC) study. The bootstrap procedure has been utilized to compute the mean and SD of the ROC area, A(z), obtained for each parameter. It has been observed that combining normalized Nakagami parameters from two images of the mass may help to improve classification performance over that from utilizing the parameters of just a single image. The performance of this automated parameter-based approach appears to match that of a trained radiologist.
Classification of breast masses in ultrasonic B-scan images is undertaken using a multiparameter approach. The parameters are generated on the basis of a non-Rayleigh statistic model of the backscattered envelope from the breast tissue. They can be computed automatically with minimal clinical intervention once the location of the mass is known. A new discriminant is developed that combines these parameters linearly. It is seen that this new discriminant performs classification of masses into benign or malignant better than the classification by any one of the individual parameters. The data set studied consisted of 99 cases (70 patients with benign masses and 29 patients with malignant masses). The areas under the receiver operating characteristic (ROC) curves (Az) and statistical attributes of the areas were studied to establish the enhancement in performance. The Az value after combining all the parameters was found to be 0.8701. Upon combining this parameter with the level of suspicion (LOS) scores of a radiologist, the performance is further enhanced with an area under the (empirical) ROC of 0.94 having an operating point at a sensitivity of 0.965 and specificity of 0.87. It is suggested that this automated approach may hold promise as a means of classifying breast masses.
The purpose was to evaluate the inter-visit, inter-observer and intra-observer variation of quantitative and qualitative tendon examinations in vivo for a cohort of asymptomatic volunteers. Eleven healthy male subjects were recruited. The following tendons were assessed by ultrasonography: Achilles tendon, patellar tendon, triceps tendon, extensor pollicis longus, flexor carpi radialis and supraspinatus. For each tendon a quantitative measurement of tendon size was made at a predefined anatomical location. Two experienced sonologists, blind to one another's findings, evaluated each of the tendons independently. Each tendon was evaluated on two occasions 1 week apart. No difference was found to be attributed to variation in tendon size between visits. Inter-observer variation was a source of error with intra-subject, inter-visit measurements proving more reproducible. There was some significant variation between observers. This variation was more marked with some tendon measures than others. Inter-observer variation for triceps, flexor carpi radialis and supraspinatus was most marked. Minimum detectable change in tendons varied from 13 to 57% depending on the plane of scanning and the tendon being examined. Good reproducibility of quantitative tendon measurements can be achieved within a study using two observers by following a defined scanning protocol. However, it is recommended that the same observer perform serial assessments. The data allow minimal detectable changes in tendon size to be calculated.
With this study we aimed to determine the reliability of ultrasound imaging in depicting the normal anatomy of the distal biceps tendon in human cadaver specimens and to provide an accurate visualisation of ruptures of the distal biceps tendon in healthy volunteers.
The distal biceps tendons of six whole-arm human cadaver specimens were investigated. The tendons were subsequently marked with a biopsy needle and re-examined. In addition, ultrasound imaging of the distal biceps tendon was performed in 25 healthy volunteers (50 sonograms). All examinations were carried out using linear ultrasonic transducers of various frequencies (5 - 13.5 MHz). The sonographic images were submitted to two experienced examiners for analysis.
Positive identification of the tendon was achieved in all cases. The best results were achieved using 7.5 MHz transducers. Our study also suggests that the medial longitudinal scan and the articular transversal scan are a definite prerequisite for a correct diagnosis in the region of the distal biceps tendon. The dynamic examination is very useful to visualise the tendon with sufficient accuracy.
Based on this study, ultrasound imaging is recommended as the method of choice for visualisation of the distal biceps tendon if performed with the necessary accuracy.
The aim of this prospective study was the evaluation of preoperative three-dimensional ultrasound in detecting meniscal lesions compared to preoperative MRI.
A total of 34 patients with clinical signs of meniscal lesions were examined preoperatively (11.7 MHz linear transducer) using the 3-D technique. Before ultrasound, MRI was performed, the results of which were unknown to the ultrasound examiner. The basis of the MRI result was the radiologist's written report. Arthroscopically the meniscal situation was noted and taken as reference.
At arthroscopy there were 10 lateral meniscal lesions at different locations and 47 medial meniscal lesions at different locations. The sensitivity (0.5-0.78) and specificity (0.75-0.95) of both imaging methods were overall comparable.
Ultrasound with the three-dimensional technique and high-resolution transducer in the hands of an experienced operator gives results comparable to the MRI interpretation by a general radiologist in detecting meniscal lesions.
The aim of this prospective study was to evaluate preoperative three-dimensional ultrasound scans for the detection of meniscal lesions with a special focus on interobserver reliability.
Forty one patients with clinical signs of meniscal lesions were preoperatively examined by ultrasound using the 3-D technique (11.7 MHz linear transducer). The 3-D dataset was stored and examined by a second orthopaedic surgeon. The second ultrasound examiner was blinded to the results of the first. Any meniscal pathology was confirmed arthroscopically and documented.
At arthroscopy eight lateral meniscal lesions and 57 medial meniscal lesions were detected at different locations. The sensitivity and specificity of the original ultrasound examination was acceptable whereas the results of the second ultrasound session were not as sensitive.
Three-D-ultrasound with a high resolution transducer, in the hands of an experienced operator, provides acceptable results in the detection of meniscal lesions, however, analysis of the volume dataset from the 3-D ultrasound investigation indicates that it does not offer sufficient accuracy for clinical use.
The management of patients with signs and symptoms referable to the rotator cuff depends on the presence of cuff injury and the size of the tear. Treatment options include conservative nonsurgical management for patients with an intact or partially torn cuff, arthroscopic decompression of the coracoacromial space for those not responding to nonsurgical management, and a range of surgical techniques to repair full-thickness tears. This study was designed to determine whether sonographic evaluation with classification of the extent of cuff injury is accurate for purposes of treatment planning.
Preoperative sonography of the rotator cuff was performed on 225 patients, and findings were classified into intact, partial tear, small full-thickness tear, large full-thickness tear, and massive tear groups. Surgical correlation with the predicted sonographic classification was provided by arthroscopic inspection or open surgery.
The sonographic findings were surgically confirmed for 206 (92%) of the 225 patients. More extensive cuff injury was encountered during surgery than had been predicted sonographically in 11 patients (5%); less extensive injury than predicted was found during surgery in eight patients (4%).
Our results show a high correlation between the sonographic classification of rotator cuff injury and the surgical findings. The selection of appropriate treatment programs can be reliably based on the sonographic classification.
OBJECTIVE. The management of patients with signs and symptoms referable to the rotator cuff depends on the presence of cuff Injury and the size of the tear. Treat- ment options include conservative nonsurgical management for patients with an intact or partially torn cuff, arthroscopic decompression of the coracoacromial space for those not responding to nonsurgical management, and a range of surgical tech- niques to repair full-thickness tears. This study was designed to determine whether sonographic evaluation with classification of the extent of cuff injury is accurate for purposes of treatment planning. SUBJECTS AND METHODS. Preoperative sonography of the rotator cuff was per- formed on 225 patients, and findings were classified into intact, partial tear, small full- thickness tear, large full-thickness tear, and massive tear groups. Surgical correlation with the predicted sonographic classification was provided by arthroscopic inspec- tion or open surgery. RESULTS. The sonographic findings were surgically confirmed for 206 (92%) of the 225 patients. More extensive cuff injury was encountered during surgery than had been predicted sonographically in 11 patients (5%); less extensive injury than pro- dicted was found during surgery in eight patients (4%). CONCLUSION. Our results show a high correlation between the sonographic clas- sificatlon of rotator cuff injury and the surgical findings. The selection of appropriate treatment programs can be reliably based on the sonographic classification.
In stereotactic neurosurgery, computed tomography (Cr) and magnetic resonance (MR) images are registered in a coordinate system defined with respect to the skull. By intraoperatively tracking the coordinate position of a surgical instrument, various displays can be formed which show the position of the instrument in the MR and/or Cr images. However, the accuracy of this display varies because intracranial structures may shift or warp from their position prior to surgery. Ultrasonic imaging systems provide real-time images of the brain, but structures in these images are difficult to interpret because the images are based on ultrasonic echoes. A method has been developed for the real-time registration of these images. With this registration, software continuously updates a corresponding image constructed from the set of MR and/or Cr images used for guidance. By developing this second view of the structures in the ultrasound image, the surgeon can easily interpret the ultrasound image, and it becomes possible to determine the extent of the intra-operative structure shift between the two images.
Reconstruction techniques currently used for forming pulse-echo compound scan images are reviewed. A computer based system for acquiring and storing the pulse-echo data in video line-mode form, (i.e. the detected echo waveform and deflection co-ordinates for each transmitted pulse) is described in both its hardware and software aspects.
The performance of peak detected, minimum detected, integrated and averaged reconstruction on point targets is illustrated and discussed. The properties of the various techniques in reconstructing clinical data obtained from the pregnant uterus, abdomen and breast are outlined and future clinical applications suggested.
This site introduces the application of factor analysis to chemical data. The tutorial, which uses data from a UV absorbance experiment, is designed for undergraduate chemistry students.
Vita. Thesis (M.S.)--Washington University, 1993. Dept. of Electrical Engineering. Includes bibliographical references.
The UI Octoson can provide accurate compound and simple scan cross sectional views of the heart. Sections taken in the transverse, sagittal, and other planes normal and parallel to the long axis of the heart are useful for providing full information that may be obtained by the examination. The views allow the visualization and measurement of most major structures of the heart, giving a more complete description of the geometry of the heart.
High-resolution ultrasound is an imaging technique with increasing applications in the musculoskeletal system. With the development of high-frequency, realtime transducers, detailed images of small superficial structures can be provided. Tendons, muscles, and subcutaneous tissues can be assessed for disruption, masses, or fluid collections. Foreign bodies can be localized to guide surgical excision. Increased use of this diagnostic tool may lead to new applications as the technology improves.
The signal intensity patterns of rotator cuff lesions at magnetic resonance (MR) imaging were evaluated in 80 patients who had surgical correlation and in 13 asymptomatic individuals (14 shoulders). Six cadaver shoulders were examined with MR, and histologic correlation was obtained in four. All studies were performed at 1.5 T with a flexible circular surface coil. The accuracy of MR imaging in detection of full-thickness cuff tears (31 patients) was 0.95 and of partial thickness tears (16 patients), 0.84. The most common and accurate pattern for full-thickness cuff tears (22 of 31 tears) was a region of intense signal seen on T2-weighted images. Less often the torn region consisted of an extremely degenerated and attenuated tendon with moderate signal intensity or was obscured by low-signal-intensity scar. The intense signal pattern on T2-weighted images was also accurate, although a less common finding (seven of 16 cases), in the diagnosis of partial tears. Tendinitis was recognized as focal or diffuse regions of increased signal intensity or a nonhomogeneous pattern of increased signal often associated with tendinous enlargement. In some patients, manifestations of subacromial-subdeltoid bursitis was present. Tendon degeneration was also manifested as regions of increased signal intensity. Some similarity and overlap of signal patterns of partial interstitial tears, tendinitis, and tendon degeneration are observed.
The purpose of this study was to determine the accuracy of ultrasonography in the detection of rotator cuff tears. In a prospective study of 41 patients, the ultrasound results could be compared with the combined results of (CT) arthrography, arthroscopy and operation. The sensitivity of sonography in detecting partial and total rotator cuff tears was 86%, the specificity 91%, the positive predictive value 96% and the negative predictive value 73%. In spite of the relatively small size of this series, our results are comparable with those of most other studies. Based on these results, sonography can provide a non-invasive, rapid and inexpensive diagnostic method for screening patients with shoulder complaints. A disadvantage of the method is its long learning curve.
Use of multiple look directions, that is, compound imaging, has been shown previously to increase detection of specular reflectors and averaging of speckle noise in gray-scale images, often at the expense of spatial resolution and other misregistration errors. In color flow imaging, additional view angles can fill in vessels missed due to Doppler angle dropout and increase quantitative and visual Doppler accuracy by triangulation or a simple peak-frequency-shift combination algorithm. Image registration and unwarping throughout multiple three-dimensional (3D) volume sets should correct for many refraction artifacts, motion between and during compounded image sets and even, possibly, positioning errors between image sets, acquired months apart, to display growth of abnormalities. The registration described here does not provide sufficient accuracy for formation of enhanced coherent apertures, but shows promise in some cases to provide superior compound images and possibly comparisons of current and prior studies. In this study, the breast is stabilized by mild compression between a flat plate and a scanning membrane. Registration and unwarping is performed retrospectively on two separate volumetric data sets by defining pairs of corresponding points and, in some cases, line and plane segments. Three-dimensional linear affine transforms are performed using identified points, lines and planes. 3D nonlinear warped transforms are also possible given adequate numbers of identifiable points. More than two data sets are registered by selecting one as the standard, and registering the remainder to match. The most appropriate algorithm, such as averaging or maximum amplitude, may be used to combine the data sets for display. Significant success has been achieved in compound display of a test object and of the breast in vivo, even when there was relative motion or warping between image sets. In pulse-echo imaging, homologous feature registration for compounding appears to have advantages over mechanically registered compounding methods previously employed in the breast and significant increases in lesion and structural conspicuity are noted due to a reduction in speckle noise. The improvements from compounding in 3D, surface-rendered Doppler imaging of vasculature are striking.
A spatial compounding system has been designed to improve the quality of B-mode echographic images. It consists of constructing an improved image from the combination of several different images of the same cross-sectional plane. The "final" image is constructed by the registration and the superposition of the "original" images. For this, the relative position in the space of the original images has to be known. The use of a localization articulated arm, on which the ultrasonic probe is fixed, makes this possible. The main advantages of the technique are, on one hand, the elimination of the acoustic shadows following a strong reflector structure and, on the other hand, the reduction of the speckle generated in echographic images. The method of reconstruction has been validated on agar gel phantoms and provides good accuracy. In vivo experiments on human beings have also been performed. Acoustic shadows caused by bones in cross-sectional images of the thigh and the arm are eliminated. All the contours of the femur and humerus can be observed in the final images. The reduction of speckle is shown in kidney images and the signal-to-noise ratio improvement is quantified as a function of the number of images involved in the reconstruction.
To develop an ultrasound (US) extended-field-of-view scanning technique that combines the convenience of a real-time scanner with the spatial advantages of a static B-mode scanner and provides a panoramic image in real time without position sensors or cumbersome articulated arms.
An image-registration-based position-sensing technique was used to track probe motion and reconstruct a large composite image during real-time scanning. The probe motion (translation and rotation) was estimated by combining multiple local motion vectors. This computationally intensive process required a special programmable image processor.
Large, resolution-preserved composite images up to 60 cm long were obtained. Measurement accuracy as determined with phantom experiments was better than 5%. The method could be applied to any probe or image format.
In addition to providing a panoramic image to expand diagnostic capabilities, extended-field-of-view US provides a more easily interpretable image and is an effective cross-specialty communication tool.
A variety of pearls, pitfalls, and updates related to the extremities and spine are discussed. Tricks of the trade regarding shoulder dislocations, easily missed fractures, radial head subluxation, and the approach to deep lacerations are discussed. In the pitfall section, potential difficulties in the evaluation of suspected nonaccidental trauma, compartment syndromes, partial cord syndromes, and hip pain in children are discussed. Finally, new information regarding cost-effective evaluation of knee and ankle injuries, as well as advances in ultrasound evaluation of shoulder and extremity injuries, is presented in the clinical updates section.
A miniature magnetic position sensor used for three-dimensional ultrasound imaging was tested for precision and accuracy in vitro. The sensor alone was able to locate points with root-mean-square (rms) uncertainty of 1.7 mm and accuracy of 0.05 +/- 0.62 mm over its specified operating range of 50 cm. With an ultrasound imaging system, a point was located from arbitrary viewing windows with 2.4-mm rms uncertainty and 0.06 +/- 0.68 mm accuracy. If viewing windows were limited to those representative of a typical ultrasound examination, the system could achieve rms uncertainty in point location of < 1 mm. Performance was not affected by operation of the imaging system when the sensor was mounted on an ultrasound scanhead. Sensitivity to metals in the operating environment was also measured.
In this article, a method of using ultrasound to image a residual limb is presented. The method employs a compound scanning technique to reconstruct a cross-sectional image (a slice) of the limb in a transverse plane. By scanning the limb in many transverse planes, a three-dimensional (3-D) volumetric image can be obtained from which either a transverse slice, a longitudinal cross section, or a 3-D surface of the limb can be displayed. The compound process circumvents the problems associated with the large attenuation of bones and enables reconstruction of a complete image of bones and adjoining tissues. In addition, the compound process improves the lateral resolution and reduces the speckle noise. Results obtained from a pair of thin wires, a contrast-resolution phantom, and a human limb demonstrate the beneficial effects of the compound process. To maximize the benefits, however, an accurate pixel registration in image reconstruction is essential. Sources of pixel misregistration and the potential means of minimizing misregistration are discussed.
Rotator cuff surgery is facilitated by accurate pre-operative information regarding the presence and size of cuff tears, and the extent of any cuff retraction or lamination.
A total of 117 consecutive patients who underwent shoulder ultrasound followed by surgical management were assessed, and the pre-operative ultrasound diagnoses were correlated with the operative findings.
Ultrasound was found to be reliable for the detection of full-thickness cuff tears (positive predictive value 96%). In the assessment of partial thickness tears, ultrasound produced few false positives, but failed to diagnose a significant proportion of these lesions. Lamination and other interstitial cuff pathology were not reliably detected by ultrasound. In the diagnosis of subacromial impingement, ultrasound produced few false positives (positive predictive value 95%), but did produce a significant number of false negative results (negative predictive value 66%).
Ultrasound is cheaper than MRI and arthrography, and is both non-invasive and 'dynamic'. It is reliable in the diagnosis of full-thickness cuff tears and is a useful adjunct in the diagnosis of cuff impingement and partial thickness tears, but is very much operator-dependent.
Three-dimensional echocardiography has demonstrated superiority over two-dimensional techniques in the determination of left ventricular mass and volumes. We describe a technique based on a magnetic tracking system which provides rapid three-dimensional image acquisition from multiple acoustic windows. Interactive three-dimensional border tracking and reconstruction with a piecewise smooth subdivision model accurately reproduced phantom volume (calculated volume = 1.00 true volume - 0.6 ml, r = 1.000, standard error of the estimate = 1.3 ml), in vitro heart volume (calculated volume = 1.02 true volume - 1.3 ml, r = 1.000, standard error of the estimate = 0.4 ml), in vitro heart mass (calculated mass = 0.98 true mass + 1.4 gm, r = 0.998, standard error of the estimate = 2.5 gm), and in vivo stroke volume (calculated stroke volume = 1.18 Doppler stroke volume - 17.9 ml, r = 0.990, standard error of the estimate = 2.8 ml). The three-dimensional in vivo data sets, which include views from three acoustic windows, were acquired in less than 90 seconds. We conclude that this method of three-dimensional echocardiographic data acquisition and analysis overcomes limitations inherent in currently available systems.
A system is described that rapidly produces a regular 3-dimensional (3-D) data block suitable for processing by conventional image analysis and volume measurement software. The system uses electromagnetic spatial location of 2-dimensional (2-D) freehand-scanned ultrasound B-mode images, custom-built signal-conditioning hardware, UNIX-based computer processing and an efficient 3-D reconstruction algorithm. Utilisation of images from multiple angles of insonation, "compounding," reduces speckle contrast, improves structure coherence within the reconstructed grey-scale image and enhances the ability to detect structure boundaries and to segment and quantify features. Volume measurements using a series of water-filled latex and cylindrical foam rubber phantoms with volumes down to 0.7 mL show that a high degree of accuracy, precision and reproducibility can be obtained. Extension of the technique to handle in vivo data sets by allowing physiological criteria to be taken into account in selecting the images used for construction is also illustrated.
One of the most promising applications of 3-D ultrasound (US) lies in the visualisation and volume estimation of internal 3-D structures. Unfortunately, artifacts and speckle make automatic analysis of the 3-D data sets difficult. In this study, we investigated the use of 3-D spatial compounding to improve data quality, and found that precise registration is the key. A correlation-based registration technique was applied to 3-D ultrasound data sets acquired from in vivo examinations of a human gall bladder. We found that the registration technique performed well, and visualisation and segmentation of the compounded data were clearly improved. We also demonstrated that an automatic volume estimate made from the compounded data (13.0 mL) was comparable to a labour-intensive manual estimate (12.5 mL). In comparison, automatic estimates of uncompounded data are less accurate (ranging from 13.5 mL to 16.7 mL). The registration technique also has applications in intra- and interpatient comparative studies.
The aim of this study was to investigate whether or not a magnetic position sensing system for free-hand acquisition of 3-D ultrasound images could be used to estimate liver volumes, and to study the effect of a high-caloric meal on these volumes in healthy subjects. In vitro accuracy was evaluated by scanning porcine and rabbit livers. Ten healthy subjects were examined fasting and 30 min after ingesting a high-caloric liquid meal. Portal and hepatic vein blood flow were measured by 2-D duplex sonography. The 3-D system yielded a strong correlation (r = 0.99) between true and estimated volumes in vitro. No significant increase in liver volume in response to the meal was seen. However, portal and hepatic vein flow volume increased significantly. Experience in human subjects suggests that a complete 3-D study of liver volumes can be obtained from multiple acoustic windows. In healthy subjects, no significant increase in liver volume was seen in response to ingestion of a high-caloric liquid meal.
A three-dimensional (3D) ultrasound imaging system has been used to study spatial compounding of images acquired with different scanhead positions and orientations. A compounding algorithm has been developed that assigns regional weights depending on the local incidence angle of the ultrasound beam. Compound scans were performed of bones in vitro and the shoulder rotator cuff in volunteer subjects. Border measurements (peak value and width) were compiled as a function of ultrasound beam incidence angle and compared for single views and for maximum, mean and weighted mean compounding techniques. The weighted mean produces less variability than that of the maximum and mean for both intensity and border width. The weighted method also demonstrates less blurring of borders than the maximum and mean methods. Surfaces derived from the weighted reconstructions exhibited fewer gaps and fewer spurious connections between surfaces, which could be of particular importance for automated image analysis.
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Estimation of the human liver volume and configuration using three-dimensional ultrasonography
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Three-dimensional freehand ultrasound
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