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A 54-year-old female with multiple myeloma undergoing staging FDG PET-MRI. (a) Maximum intensity projection PET image shows normal FDG biodistribution throughout the skeletal bone marrow. (b) Sagittal T2-weighted FS MRI image of the thoracolumbar spine shows diffuse T2-hyperintense marrow infiltration, consistent with diffuse involvement by multiple myeloma. (c) Corresponding fused T2-weighted FS PET-MRI image shows only normal low-grade marrow activity throughout the spine. Subsequent bone marrow biopsy demonstrated involvement by 80-90% clonal plasma cells.
Source publication
New integrated PET‐MRI systems potentially provide a complete imaging modality for diagnosis and evaluation of musculoskeletal disease. MRI is able to provide excellent high‐resolution morphologic information with multiple contrast mechanisms that has made it the imaging modality of choice in evaluation of many musculoskeletal disorders. PET offers...
Contexts in source publication
Context 1
... imaging is preferred for detection of bone lesions in patients with suspected myeloma, and one of three modalities can be used depending on availability, cost, and/or institutional preference: whole body low dose CT, whole-body MRI (WBMRI), or FDG PET/CT. The most recent IMWG consensus guidelines endorse MRI as the gold standard for imaging the axial skeleton, evaluating painful lesions, and for distinguishing benign from malig- nant compression fractures. It is recommended for the work-up of solitary bone plasmacytoma, and the IMWG recommends whole-body MRI, or spine and pelvic MRI at minimum, in all patients with smoldering or asymptomatic myeloma. 63 18 F-FDG PET/CT should be used to confirm a diagnosis of solitary plasmacytoma if whole-body MRI is unavailable, and to differentiate between smoldering and active myeloma, if whole-body x-ray is negative and WBMRI is unavailable. FDG PET/CT is also the preferred functional imaging modality to evaluate and monitor ther- apy. 64 There is no current consensus statement on the use of FDG PET-MRI in myeloma patients from the IMWG, but it has been incorporated into the diagnostic algorithm at several institutions. 65 MRI has been proven to be more sensitive in depicting MM lesions than radiographs, except for rib lesions. 66 Up to 50% of patients with a normal radiographic skeletal survey have lesions depicted on MRI. 67,68 On MRI, myelomatous lesions appear as T 1 hypointense areas of marrow replacement, with increased signal on T 2 or short tau inversion recovery (STIR)-weighted images. Five patterns of marrow involvement have been recognized: normal, focal, diffuse (homogenous or heterogeneous), variegated (also referred to as "salt and pepper"), or a combination thereof. 67 Importantly MRI depicts marrow infiltration and replacement, while radiographs and CT illustrate osseous destruction, and because of this MRI has superior detection of bone marrow involvement compared with LDWBCT or PET/CT, with a specific advantage in the diffuse patterns of involvement. 69-71 Incorporation of DWI results in superior lesion conspicuity compared with conventional STIR and contrast-enhanced MRI, 72,73 and ADC values can be used with excellent accuracy (90% sensitivity and 93% specificity) to differentiate diseased and normal marrow. 74 Quantitative ADC analysis has shown particular value in determining diffuse involvement; a bone marrow ADC greater than 0.548 3 10 23 mm 2 /s has been shown to be 100% sensitive and 98% specific for diagnosing a diffuse marrow pattern. 75 MRI also confers prognosis; the presence of more than one focal lesion on MRI is an independent predictor of pro- gression to symptomatic disease and development of osteo- lytic bone lesions. 76,77 The diffuse pattern of involvement has been correlated with worse prognosis, greater burden of disease, and high-risk cytogenetics. 78,79 MRI's ability to demonstrate focal and diffuse disease and the quantitative potential of ADC hold promise for monitoring treatment response. Positive response on conventional MRI sequences includes decrease in size and/or number of focal lesions, normalization of a diffuse pattern, and in focal lesions, the appearance of a peripheral halo of T 1 hyperintense fatty marrow, or complete fatty replacement, also called fatty metamorphosis. It has been also been shown that mean ADC increased in 95% of MM responders and a 3.3% ADC increase resulted in 90% sensitivity and 100% specif- icity in detecting positive treatment response, 80 which has been supported by other studies. 74 Like MRI, FDG PET/CT is more sensitive than radio- graphs, 67,68,70 and performs equally well to MRI in detect- ing focal lesions, but is inferior for detecting diffuse disease. 67-71 Some studies have shown correlation between SUVmax on PET/CT and bone marrow cellularity and plasma cell ratios on bone marrow biopsy sample. 81 PET/ CT also has excellent ability for detecting extramedullary disease (EMD), 82 which is important given that approxi- mately 10% of MM patients will develop EMD during the course of their disease. 83 The prognostic value of FDG PET/CT is better estab- lished than MRI. The presence of three or more lesions is an independent predictor of overall survival (OS), 84 while a SUVmax of greater than 4.2 and presence EMD adversely affect progression free (PFS) and OS. 85 A positive PET/CT has also been associated with quicker progression of smol- dering myeloma to active myeloma. 86 Interestingly, some studies have shown higher probability of progression if focal FDG avid lesions also exhibit osteolysis, 87 while others have not shown osteolysis on PET/CT to be predictive. 86 Despite this, the updated IMWG guidelines necessitate the presence of osteolysis to make the diagnosis of active disease on PET/CT. 62 The benefit of FDG PET/CT in assessing treat- ment response was well-demonstrated in a recent meta- analysis combining 10 studies involving 690 myeloma patients. 88 PET/CT may demonstrate disease response earlier than MRI, as resolution of FDG activity is typically seen before MRI signal normalization. 89,90 A negative PET/CT after therapy is an independent predictor for prolonged PFS and OS in patients with complete response. 91 The literature detailing PET-MRI performance in mul- tiple myeloma is limited. A study comparing WBMRI and PET/CT in assessment of active disease in MM found better sensitivity and specificity for MRI, but noted that when used in combination, PET and WBMRI were found to have a specificity and positive predictive value of 100%, herald- ing a role for integrated PET-MRI. 92 Another study showed equivalency of PET/CT and PET-MRI for detection of mye- loma lesions in 30 patients; finding 94% of focal lesions identified on the PET portion of PET/CT were also seen on the PET portion of PET-MRI. PET-MRI missed rib lesions that were seen on PET/CT evaluation, not surprising given that WBMRI has documented limitations in evaluation of skull, ribs, and clavicles. 66 In conclusion, PET-MRI in mul- tiple myeloma shows vast potential given the high accuracy of both PET/CT and MRI to detect focal lesions, MRI's advantage in diffuse disease, prognostic information afforded by both, and PET's well-evidenced ability to determine response to therapy. In our personal experience, PET-MRI has been helpful in cases of diffuse disease, better depicted on MRI than PET (Fig. 2), and also in showing resolution of FDG activity in responding lesions before resolution of signal abnormality on MRI (Fig. ...
Context 2
... vast potential given the high accuracy of both PET/CT and MRI to detect focal lesions, MRI's advantage in diffuse disease, prognostic information afforded by both, and PET's well-evidenced ability to determine response to therapy. In our personal experience, PET-MRI has been helpful in cases of diffuse disease, better depicted on MRI than PET (Fig. 2), and also in showing resolution of FDG activity in responding lesions before resolution of signal abnormality on MRI (Fig. ...
Citations
... This opens up the possibility of assessing the function of metabolic activity in OA using positron emission tomography (PET) markers while also relating them to qualitative MRI measures of OA bone diseases. 13 The aim of our study was to assess the potential of simultaneous 18F-NaF PET/MRI to identify as well as classify osseous metabolic abnormalities in knee OA and to see if degenerative changes in the cartilage and bone on MRI might be correlated with subchondral 18F-NaF uptake on PET. ...
... While bone pathology has traditionally been assumed to play a significant role in the evolution of OA, the etiology, activity, as well as progression of the disease is still unknown. 13,19 The susceptibility of 18F-NaF PET to osteoblastic activities was exhibited in this investigation, as well as its ability to quantify remodeling of subchondral bone and also other metabolic anomalies in OA bone pathology. ...
Background Articular cartilage (AC) loss and deterioration, as well as bone remodeling, are all symptoms of osteoarthritis (OA). As a result, an ideal imaging technique for researching OA is required, which must be sensitive to both soft tissue and bone health.
Objective The aim of this study was to assess the potential of simultaneous 18F sodium fluoride (18F-NaF) positron emission tomography/magnetic resonance imaging (PET/MRI) to identify as well as classify osseous metabolic abnormalities in knee OA and to see if degenerative changes in the cartilage and bone on MRI might be correlated with subchondral 18F-NaF uptake on PET.
Methods Sixteen (32 knees) volunteers with no past history of knee injury, with or without pain, were enrolled for the research from January to July 2021. The images of both knees were taken utilizing an molecular magnetic resonance (mMR) body matrix coil on a simultaneous PET/MRI biograph mMR. The acquisition was conducted after 45 minutes of intravenous infusion of 18F-NaF 185–370 MBq (5–10 mCi) over one PET bed for 40 minutes, while MRI sequences were performed simultaneously.
Results All pathologies showed significantly higher maximum standardized uptake value (SUV max ) than the background. Thirty-four subchondral magic spots were identified on 18F-NaF PET without any structural alteration on MRI. Bone marrow lesions (BMLs) and osteophytes with higher MRI osteoarthritis knee score (MOAKS) score showed higher 18F-NaF uptake (grade1˂grade2˂grade3). BMLs had corresponding AC degeneration. There was discordance between grade 1 osteophytes (86.6%), sclerosis (53.7%) and grade 1 BML in cruciate ligament insertion site (91.66%); they did not have high uptake of 18F-NaF. In case of cartilage, there was significant difference between AC grades and average subchondral SUV max and T2* relaxometry (grade0˂grade1˂grade2˂grade3˂grade4). BMLs are much more metabolically active than other pathologies, while sclerosis is the least. We also found that the subchondral uptake was statistically increased in the areas of pathology:
Conclusion 18F-NaF PET/MRI was able to detect knee abnormalities unseen on MRI alone and simultaneously assessed metabolic and structural markers of knee OA across multiple tissues in the joint. Thus, it is a promising tool for detection of early metabolic changes in OA.
... The questions are designed to find out about pain attacks, tactile and thermal hypersensitivity, tingling, prickling, and insensibility. Imaging techniques such as computed tomography (CT scan), positron emission tomography (PET scan), and magnetic resonance imaging (MRI) are performed in case of a requirement to detect nerve compression and nerve infiltration [37]. Various laboratory tests need to be performed on certain neuropathic pain conditions, including microneurography (a minimally invasive technique to record nerve fiber activity), nerve biopsy, skin biopsy, and punch biopsy [38,39]. ...
Neuropathic pain affects more than one million people across the globe. The quality of life of people suffering from neuropathic pain has been considerably declining due to the unavailability of appropriate therapeutics. Currently, available treatment options can only treat patients symptomatically, but they are associated with severe adverse side effects and the development of tolerance over prolonged use. In the past decade, researchers were able to gain a better understanding of the mechanisms involved in neuropathic pain; thus, continuous efforts are evident, aiming to develop novel interventions with better efficacy instead of symptomatic treatment. The current review discusses the latest interventional strategies used in the treatment and management of neuropathic pain. This review also provides insights into the present scenario of pain research, particularly various interventional techniques such as spinal cord stimulation, steroid injection, neural blockade, transcranial/epidural stimulation, deep brain stimulation, percutaneous electrical nerve stimulation, neuroablative procedures, opto/chemogenetics, gene therapy, etc. In a nutshell, most of the above techniques are at preclinical stage and facing difficulty in translation to clinical studies due to the non-availability of appropriate methodologies. Therefore, continuing research on these interventional strategies may help in the development of promising novel therapies that can improve the quality of life of patients suffering from neuropathic pain.
... PET/MRI has benefits of the two different techniques in one and compensates for the drawbacks of each technique. 1 OA is a multifaceted condition that affects both cartilage and bone tissue. Its pathophysiology is complicated by local, metabolic, and genetic variables that cooperate to promote cartilage degeneration, proliferative subchondral bone reaction, joint-space narrowing (JSN), subchondral sclerosis, and inflammation of the synovium. ...
... These advances have been harnessed and further augmented through the development of dual-modality scanners, including combined positron emission tomography (PET)-CT and PET-MRI. These systems enable spatial and temporal linkage of metabolic activity with structural data, as in the investigation of the interaction between inflammation and bone damage in inflammatory arthritis, between increased glycolysis and sites of synovitis and tenosynovitis, and between the uptake of labeled fluoride marking bone formation alongside structural evidence cartilage damage or metabolic bone disorders [43][44][45]. Whether using multiple separate scanners or a single dual-modality scanner for data acquisition from a single patient and anatomic site, challenges arise when attempting to quantify metrics of bone quality. The most challenging aspects of multimodality analysis are spatial co-registration and limited spatial resolution compared to the structures of interest. ...
Purpose of Review
In this paper, we discuss how recent advancements in image processing and machine learning (ML) are shaping a new and exciting era for the osteoporosis imaging field. With this paper, we want to give the reader a basic exposure to the ML concepts that are necessary to build effective solutions for image processing and interpretation, while presenting an overview of the state of the art in the application of machine learning techniques for the assessment of bone structure, osteoporosis diagnosis, fracture detection, and risk prediction.
Recent Findings
ML effort in the osteoporosis imaging field is largely characterized by “low-cost” bone quality estimation and osteoporosis diagnosis, fracture detection, and risk prediction, but also automatized and standardized large-scale data analysis and data-driven imaging biomarker discovery.
Summary
Our effort is not intended to be a systematic review, but an opportunity to review key studies in the recent osteoporosis imaging research landscape with the ultimate goal of discussing specific design choices, giving the reader pointers to possible solutions of regression, segmentation, and classification tasks as well as discussing common mistakes.
... W onkologii badanie PET przeprowadzane jest w celu określenia stopnia zaawansowania nowotworu, wykrycia przerzutów odległych, a także monitorowania skuteczności zastosowanego leczenia. Metoda PET/CT pozwala wskazać obszary zapalne, ocenić złamania patologiczne i wskazać obszary zwiększonej aktywności metabolizmu wybranego radiofarmaceutyku [6][7]. ...
... 18 F-FDG wykorzystywany jest do oceny obszarów podwyższonej utylizacji glukozy: zmian zapalnych, guzów nowotworowych. 18 mineralizacji, w tym: gojących się złamań, a także przerzutów odległych układu kostnego [6,8]. Autorzy [6] sugerują ponadto potencjalną użyteczność metody PET/MRI w diagnostyce MSD. ...
... 18 mineralizacji, w tym: gojących się złamań, a także przerzutów odległych układu kostnego [6,8]. Autorzy [6] sugerują ponadto potencjalną użyteczność metody PET/MRI w diagnostyce MSD. ...
Techniki obrazowe z zakresu medycyny nuklearnej znajdują szerokie zastosowanie w ocenie licznych jednostek chorobowych, w tym – schorzeń układu ruchu. Wśród najczęściej wykorzystywanych metod radioizotopowych, wyróżniamy: scyntygrafię trójfazową (z ang. triple-phase scintigraphy), tomografię emisyjną pojedynczego fotonu (z ang. single-photon emission tomography, SPECT) oraz pozytonową tomografię emisyjną/tomografię komputerową (z ang. positron emission tomography/computed tomography, PET/CT).
... In our study, the WB-PET/MRI allowed the detection of all patients with bone metastases and lymph node involvement whereas the CT-CAP and liver MRI combination missed all bone metastases and 75% of lymph node involvement. This is in agreement with literature data which highlight the potential of the PET/MRI in malignant musculoskeletal disease [25]. In addition, combining the WB-MRI with PET data favors the detection of bone lesions especially when compared to WB-PET/CT as is reported in breast cancer [26]; in our study, half of bone lesions were visible only on MRI sequences without visualization on PET. ...
Optimal HCC therapeutic management relies on accurate tumor staging. Our aim was to assess the impact of 18F-FDG-WB-PET/MRI on HCC metastatic staging, compared with the standard of care CT-CAP/liver MRI combination, in patients with HCC referred on a curative intent or before transarterial radioembolization. One hundred and four consecutive patients followed for HCC were retrospectively included. The WB-PET/MRI was compared with the standard of care CT-CAP/liver MRI combination for HCC metastatic staging, with pathology, followup, and multidisciplinary board assessment as a reference standard. Thirty metastases were identified within 14 metastatic sites in 11 patients. The sensitivity of WB-PET/MRI for metastatic sites and metastatic patients was significantly higher than that of the CT-CAP/liver MRI combination (respectively 100% vs. 43%, p = 0.002; and 100% vs. 45%, p = 0.01). Metastatic sites missed by CT-CAP were bone (n = 5) and distant lymph node (n = 3) in BCLC C patients. For the remaining 93 nonmetastatic patients, three BCLC A patients identified as potentially metastatic on the CT-CAP/liver MRI combination were correctly ruled out with the WB-PET/MRI without significant increase in specificity (100% vs. 97%; p = 0.25). The WB-PET/MRI may improve HCC metastatic staging and could be performed as a “one-stop-shop” examination for HCC staging with a significant impact on therapeutic management in about 10% of patients especially in locally advanced HCC.
... 1 Magnetic resonance imaging (MRI) has evolved as a valuable diagnostic tool for OA research because it can evaluate molecular level pathology of whole joint thematically that are not visible on radiography by using traditional MRI as well as advanced methods, i.e., compositional MRI but functional bone imaging poses a hurdle. 2 Positron emission tomography (PET) has an idiosyncratic ability to provide quantitative data on physiological as well as molecular activity, which can often harbinger structural and biochemical alterations but it requires the assistance of higher-resolution morphological information in order to locate these physiologic events. 3 As a result, it's plausible to conceptualise that the integrated PET/MRI system allows comprehensive imaging of the entire joint, has a lot of potential for studying complex disease processes in OA 4 and to harness its potential to study efficacy of disease modifying osteoarthritic drug (DMOAD). In this regard recent work was exploring the role of 18FeNa Fluoride which is a marker of bone remodelling 5 together with MRI in early detection of OA on simultaneous PET/ MRI. ...
Osteoarthritis (OA) is a debilitating disease generally of old age manifested as degeneration of articular cartilage. With no definitive treatment available, ongoing research aims at early detection and use specific noninvasive imaging markers to monitor therapeutic efficacy of disease modifying osteoarthritic drug (DMOAD) to reverse or/and arrest the disease process. Articular cartilage degradation and loss, as well as bone remodelling, are typical biomarkers of OA. As a result, an ideal imaging technique for early detection of OA is required, which must be sensitive to both soft tissue and bone health. PET/MRI is emerging as an imaging tool which can be used to study the underlying pathogenesis of OA as it enables us to assess molecular activity with PET markers while also linking them to qualitative and quantitative MRI indices of OA. In this regard recent work was exploring the role of 18F–Na Fluoride which is a marker of bone remodelling together with MRI in early detection of OA on simultaneous PET/MRI. In this article we intend to present different patterns of OA (mild to severe stages of OA) that we had observed on 18F-Sodium Fluoride (18F–NaF) PET/MRI.
... The stationary and rigid components with known coordinates, like the fixed rigid coils as well as table, are usually corrected at their known coordinates for their usage in calculating AC templates. Geometry and position uncertainty of flexible radiofrequency (RF) coils pose problems in AC computation [121]. New methods have demonstrated the capability of detecting the position of flexible MRI surface coils by utilizing 3D cameras [122], UTE sequences [123], or MR visible markers [124]. ...
Osteoarthritis (OA) is a common degenerative disorder of the articular cartilage, which is associated with hypertrophic changes in the bone, synovial inflammation, subchondral sclerosis, and joint space narrowing (JSN). Radiography remains the first line of imaging till now. Due to the lack of soft-tissue depiction in radiography, researchers are exploring various imaging techniques to detect OA at an early stage and understand its pathophysiology to restrict its progression and discover disease-modifying agents in OA. As the OA relates to the degradation of articular cartilage and remodeling of the underlying bone, an optimal imaging tool must be sensitive to the bone and soft tissue health. In that line, many non-invasive imaging and minimally invasive techniques have been explored. Out of these, the non-invasive compositional magnetic resonance imaging (MRI) for evaluation of the integrity of articular cartilage and positron emission tomography (PET) scan with fluorodeoxyglucose (FDG) and more specific bone-seeking tracer like sodium fluoride (18F-NaF) for bone cartilage interface are some of the leading areas of ongoing work. Integrated PET-MRI system, a new hybrid modality that combines the virtues of the above two individual modalities, allows detailed imaging of the entire joint, including soft tissue cartilage and bone, and holds great potential to research complex disease processes of OA. This narrative review attempts to signify individual characteristics of MRI, PET, the fusion of these characteristics in PET-MRI, and the ongoing research on PET-MRI as a potential tool to understand the pathophysiology of OA.
... In this setting, PET and MRI imaging could represent the state-of-theart present and future of diagnostic imaging that allows information of bone and soft tissues physiology, which would otherwise require invasive diagnostic methods (such as bone biopsies) or lack spatial specificity (serum markers). This will provide new insights into the pathogenesis of neoplastic, inflammatory and infective processes, leading to the identification of new targets of treatment and also to a precise monitoring of response to therapy [6,7]. ...
Musculoskeletal (MSK) pathologies are one of the leading causes of disability worldwide. However, treatment options and understanding of pathogenetic processes are still partially unclear, mainly due to a limited ability in early disease detection and response to therapy assessment. In this scenario, thanks to a strong technological advancement, structural imaging is currently established as the gold-standard of diagnosis in many MSK disorders but each single diagnostic modality (plain films, high-resolution ultrasound, computed tomography and magnetic resonance) still suffer by a low specificity regarding the characterization of inflammatory processes, the quantification of inflammatory activity levels, and the degree of response to therapy. To overcome these limitations, molecular imaging techniques may play a promising role. Starting from the strengths and weaknesses of structural anatomical imaging, the present narrative review aims to highlight the promising role of molecular imaging in the assessment of non-neoplastic MSK diseases with a special focus on its role to monitor treatment response.
... In this work, we showed that there are significant differences in quantitative [ 18 F] NaF uptake parameters between normal-appearing regions in Healthy-group knees and normal-appearing regions in OA-group knees. This adds further evidence to prior work which has hypothesized that increased bone metabolic activity may serve as an early marker of OA disease 40 . However, additional work is necessary to study longitudinal relationships between increased [ 18 F]NaF uptake and disease onset and progression. ...
Objective
Molecular information derived from dynamic [ ¹⁸F]sodium fluoride ([ ¹⁸F]NaF) PET imaging holds promise as a quantitative marker of bone metabolism. The objective of this work was to evaluate physiological mechanisms of [ ¹⁸F]NaF uptake in subchondral bone of individuals with and without knee osteoarthritis (OA).
Methods
Eleven healthy volunteers and twenty OA subjects were included. Both knees of all subjects were scanned simultaneously using a 3T hybrid PET/MRI system. MRI MOAKS assessment was performed to score the presence and size of osteophytes, bone marrow lesions, and cartilage lesions. Subchondral bone kinetic parameters of bone perfusion (K 1), tracer extraction fraction, and total tracer uptake into bone (K i) were evaluated using the Hawkins 3-compartment model. Measures were compared between structurally normal-appearing bone regions and those with structural findings.
Results
Mean and maximum SUV and kinetic parameters K i, K 1, and extraction fraction were significantly different between Healthy subjects and subjects with OA. Between-group differences in metabolic parameters were observed both in regions where the OA group had degenerative changes as well as in regions that appeared structurally normal.
Conclusions
Results suggest that bone metabolism is altered in OA subjects, including bone regions with and without structural findings, compared to healthy subjects. Kinetic parameters of [ ¹⁸F]NaF uptake in subchondral bone show potential to quantitatively evaluate the role of bone physiology in OA initiation and progression. Objective measures of bone metabolism from [ ¹⁸F]NaF PET imaging can complement assessments of structural abnormalities observed on MRI.
