Whole-body MRI Research Articles

MRI-Based Phenotyping for Osteosarcopenic Adiposity in Subjects from a Population-Based Cohort

Objective: Imaging biomarkers of bone, muscle, and fat by magnetic resonance imaging (MRI) may depict osteopenia, sarcopenia, and adiposity as the three different conditions of osteosarcopenic adiposity (OSA). Methods: Subjects from a prospective, population-based case–control study underwent a health assessment and 3 Tesla whole-body MRI scan. Imaging biomarkers of bone (bone marrow fat-fraction (BMFF)), skeletal muscle (skeletal muscle FF (SMFF)), and fat (total adipose tissue (TAT)) were determined. Participants were allocated to one phenotype according to the OSA complex. Results: Among 363 participants forming the study cohort, 81 (22.3%, 48.1% males, 62.4 ± 6.9 years) were allocated into the OSA subgroup. Participants with an OSA phenotype were significantly older compared to all remaining subjects and showed the highest grades of SMFF (all p < 0.005). Together with subjects from the osteopenic sarcopenia group, OSA subjects exhibited the highest amounts of BMFF and together with the three other adiposity-containing subgroups also exhibited the highest BMIs. The highest prevalence of an impaired glucose tolerance as well as significantly higher blood pressure, blood dyslipidemia, and hepatic steatosis was found in the OSA subgroup (all p < 0.005). Conclusions: MR biomarkers of bone, skeletal muscle and fat are feasible for body composition phenotyping and may allow for targeted risk stratification in suspected OSA syndrome.

A SPINAL TRAUMA, A TUMOR AND EVERYTHING IN BETWEEN

Introduction Burkitt lymphoma is a male predominant (3:1 male:female ratio) aggressive B-cell non-Hodgkin lymphoma that can present as a sporadic variant with meningeal involvement in about 20% of cases. Therefore, it can manifest with neurologic deficits due to compression of the spinal cord or spine nerve root. Case Report We report the case of a 6 years-old girl who presented in the emergency department following a traumatic vertebral injury (fall from around 1.5 meters) with no spinal cord involvement. She accused upper back pain, walking and orthostatism difficulties and manifested a light to moderate inferior paraparesis (MCR 3/5) The MRI revealed a space-occupying epidural mass between T1-T4, severely compressing the spinal cord initially thought to be an epidural hematoma. Emergency surgery was performed with duro-radicular decompression and mass excision through a T1-T4 laminotomy followed by a laminoplasty. The unveiled mass was white, minimally vascularized and adherent to the dura raising the suspicion of a tumor. Postoperatively the patient exhibited significant neurological improvement with resolution of the paraparesis and normal gait restoration. Three weeks later, the patient returned with complaints of abnormal gait, lumbar pain radiating in the right lower leg and upon examination a light right lower limb monoparesis (MRC 4/5) following another traumatic event. Emergency MRI of the whole spine with contrast was requested just as the pathologist in charge of the case suggested a diagnosis of Burkitt lymphoma, prompting a whole-body MRI. A severe recurrence was noted at the site of the previous lesion along with a new lumbar lesion, and several intraabdominal, intrathoracic, ovarian tumor sites with diffuse infiltration of the bone marrow. The patient was urgently referred to the pediatric oncology department and started on steroidal anti-inflammatory treatment and chemotherapy. Conclusions Burkitt lymphoma involving the nervous system in children requires increased medical attention during the clinical, histopathological examination and treatment phase, due to the association with advanced disease and, although rare, should be considered as a differential diagnosis in pediatric patients with epidural lesions. The management of such lesions demands a solid collaboration between neurosurgeon, pediatrician, pathologist and oncologist for an early diagnosis and proper treatment.

NIMG-02. DEVELOPING A RADIOMIC HIERARCHICAL GAUSSIAN PROCESS BOOSTING MODEL TO PREDICT PRIMARY TUMOR ORIGIN FROM MULTICENTRIC LONGITUDINAL MRI DATA OF BRAIN METASTASES

Abstract Focal neurologic deficits due to brain metastases might be the initial presentation in patients with cancer. Common approaches to investigate the occult primary malignancy include a whole-body PET-CT, whole-body MRI, studying tumor markers, or histopathological examination. Most of these modalities are expensive, time-consuming, invasive, and delay treatment. The field of radiomics leverages quantitative features extracted from images to improve the decision-making process in clinical practices. Although not easily understandable, these features are proxies for the tumor’s shape, contour, texture, and intensity patterns. They can help understand tumor heterogeneity, predict tumor behavior, and assess treatment response. We propose a robust radiomic workflow using longitudinal MRI data from 914 high-resolution imaging studies from 12 different centers (Ocaña-Tienda et al. (2023), Ramakrishnan et al. (2023), Wang et al. (2023)) to predict the origin of brain metastases from brain MRI scans. After using ensemble feature selection methods, we trained three fixed-effects and one mixed-effects multiclass classification model to account for longitudinal data. Fixed-effects logistic regression and support vector kernel models performed the worst (AUC 0.74 and 0.75, respectively), while the random forest performed better (AUC 0.97). The mixed-effects hierarchical Gaussian process boosting (GPBoost) model performed the best with an accuracy of 85.8%, precision of 85.4%, sensitivity of 85.8%, specificity of 95.7%, and an AUC of 0.98. In one-versus-rest classification, the GPBoost model identified the primary tumor as melanoma with the highest accuracy (96.1%) and non-small cell lung cancer with the lowest accuracy (89.0%). Developing such models holds great promise in reducing patient and institutional costs, improving time to effective treatment, and enhancing overall survival rates through personalized therapy approaches. In the future, we hope that incorporating newer patient data and refining the model to improve external validity would enable more accurate and generalizable predictions, leading to better clinical outcomes across diverse populations.

A rare presentation of isolated intraosseous Rosai-Dorfman disease of the tibia – The role of whole-body magnetic resonance imaging in management

Rosai–Dorfman disease (RDD) is a rare non-Langerhans histiocytic disorder, usually presenting with enlarged cervical lymph nodes. Extranodal involvement is quite common and synchronously involves the nasal cavity, paranasal sinuses, skin, orbit, central nervous system, and rarely bones. Isolated bone involvement is rare and can present with local symptoms such as pain, swelling, restriction of activity, and occasionally pathological fracture. The most common sites of osseous RDD are the cranium, facial bones, and tibia, in decreasing order of frequency. Imaging findings of primary osseous RDD can be variable and there are no key features to diagnose this entity with certainty. Hence, the primary role of imaging is to plan the management and post-treatment follow-up. Here, we present a case of primary osseous RDD involving tibial diaphysis and emphasize the importance of whole-body magnetic resonance imaging in ruling out systemic involvement.

Design and operation of a whole-body MRI scanner without RF shielding.

To investigate how a clinical MRI system can be operated without an RF cabin. Receive interference cancellation via signal processing and active transmit emission suppression are evaluated for mitigating image artifacts and achieving electromagnetic compatibility. A clinical whole-body MR scanner with B0 = 0.55 T was placed in an environment without RF shielding. The signals of 16 additional auxiliary receive antenna elements outside the scanner bore were used to remove interference from the wanted MR signal via a dedicated sidelobe cancellation algorithm. In vivo measurements with different MR sequences were performed in the presence of ambient RF noise and additional artificial interferers, covering brain and abdominal applications. To investigate the transmit electromagnetic compatibility, simulations with different auxiliary transmit antenna arrangements and body coil loading conditions were performed, and their emission suppression performance in the far field was evaluated. The MR sidelobe cancellation algorithm successfully removed interference artifacts up to more than 3 times of the wanted MR image energy; difference images carried little to no visibly removed wanted signal. According to the simulations, electromagnetic compliance can be achieved with 32 or more auxiliary transmit antennas. The number and placement of sensor points are essential. A whole-body 0.55T MR scanner can be operated without RF shielding. Image artifacts from external interference can be removed, requiring only a modest number of auxiliary antennas. Electromagnetic compliance appears to be achievable using active transmit cancellation, but the required hardware efforts may not be practical.

Whole-body MRI-based long-term evaluation of pediatric NF1 patients without initial tumor burden with evidence of newly developed peripheral nerve sheath tumors

BackgroundPatients with neurofibromatosis type 1 (NF1) can develop plexiform neurofibromas (PN). Large tumor burden is a predictor for the development of malignant peripheral nerve sheath tumors. Whole-body magnetic resonance imaging (WB-MRI) is the recommended imaging method for the evaluation of PN. WB-MRI is recommended for NF1 patients at transition from adolescence to adulthood. In the absence of internal PN further follow-up WB-MRI is not considered necessary. PN are often detected in early childhood, leading to the assumption that they may be congenital lesions. It remains unclear whether this invariably applies to all patients or whether patients who initially displayed no tumors can still develop PN over time. Therefore, we retrospectively reviewed WB-MRI scans of pediatric patients with NF1 without initial tumor burden and compared these with long-term follow-up scans for presence of newly developed PN.MethodsWe retrospectively reviewed WB-MRI scans of 17 NF1-children (twelve male; median age at initial scan: 9 [IQR 6.1–11.9] years) who initially displayed no PN. MRI scans with a follow-up interval of at least 6 years (median follow-up interval: 9 [IQR 5.6–12.4] years) were reviewed in consensus by two radiologists regarding the development of new PN over time.ResultsNew PN were identified in two out of 17 children without initial tumor burden in follow-up examinations. One of these two patients developed two larger distinct PN of 4.5 cm on the right upper arm and of 2.5 cm on the left thoracic wall between the age of ten and twelve. The second child developed multiple smaller PN along the major peripheral nerves between the age of eleven and 16. In addition, 15 of the children without initial tumor burden did not develop any distinct tumors for a period of at least 6 years.ConclusionOur results indicate that PN can be newly detected in pediatric patients over time, even if no PN were detected on initial MRI scans. Therefore, it seems reasonable to perform at least a second MRI in pediatric NF1 patients at transition to adulthood, even if they did not display any tumor burden on initial MRI, and when the MRI was performed significantly under the age of 18. With this approach, tumors that may have developed between scans can be detected and patients at risk for complications can be identified.

Unusual Signal of Lymphadenopathy in Children with Nodular Sclerosing Hodgkin Lymphoma.

The current guidelines for initial cross-sectional imaging in pediatric lymphomas involve computed tomography (CT) of the chest, abdomen, and pelvis. However, whole-body magnetic resonance imaging (MRI) can be favored over CT for diagnosing and staging the disease, given its lack of ionizing radiation and its higher tissue contrast. Imaging characteristics of lymphoid tissue on MRI include a high T2/short tau inversion recovery (STIR) signal. A low or intermediate signal of lymphadenopathy on T2 and STIR images is an unexpected finding, noted anecdotally in nodular sclerosing Hodgkin lymphoma. This signal may be characteristic of a histological subtype of the disease and, if confirmed, could potentially be used to avoid biopsy. In this study, we aimed to review signal characteristics of lymphadenopathy in patients with biopsy-confirmed nodular sclerosing Hodgkin lymphoma. We undertook a retrospective review of relevant MR studies of patients with nodular sclerosing Hodgkin lymphoma. Studies were reviewed by an experienced pediatric radiologist regarding lymph node signal, especially on T2/STIR. Eleven children with nodular sclerosing Hodgkin lymphoma were included. Median age at the time of MRI was 14.3 (IQR: 13.9-16.1) years, and nine were boys. Five patients showed some lymphadenopathy with a low T2/STIR signal, and six showed an intermediate T2/STIR signal. Central gadolinium non-enhancement was observed in four patients. All eleven patients (100%) with a diagnosis of nodular sclerosing Hodgkin lymphoma showed some lymphadenopathy with a low or intermediate T2/STIR signal, and five children (45.5%) showed a frank low signal of some lymphadenopathy, a feature which may prove to be a biomarker for this histology.

Ultrasonographic liver nodules are more often benign lesions in dogs with hemoperitoneum secondary to splenic tumor rupture.

To evaluate the reliability of preoperative abdominal ultrasonography as a staging tool for dogs with hemoperitoneum due to presumed splenic tumor rupture, focusing on the detection of metastatic lesions in the liver. 99 dogs from 20 emergency and specialty hospitals across the US. Dogs with nontraumatic hemoperitoneum secondary to splenic tumor rupture were included. A post hoc analysis was conducted on data from a nationwide prospective trial investigating novel treatments for canine hemangiosarcoma. The accuracy of preoperative staging was assessed by comparing ultrasonographic findings with intraoperative observations and histologic findings. On preoperative ultrasonography, there was a 20% incidence of liver lesions identified, with no association to liver lesions seen during operation. Notably, 22% of liver lesions observed during operation were missed on preoperative ultrasonography. The presence of liver lesions on preoperative ultrasonography was associated with a higher likelihood of a benign splenic tumor diagnosis. There was no association between the identification of liver lesions on preoperative ultrasonography and the presence of metastatic disease on liver biopsy, with a sensitivity and specificity of 19% and 82%, respectively. Additionally, ultrasound had low sensitivity in detecting intra-abdominal lesions beyond the liver and spleen, with 82% of these lesions missed preoperatively. This study challenges conventional perceptions around the approach to staging in dogs with hemoperitoneum. These findings advocate for a reevaluation of the staging approach, with more comprehensive modalities like whole-body CT or MRI potentially being more warranted.

P112 Whole-body MRI vs. 68Ga-PSMA PET/CT for staging of high-risk prostate cancer

P112 Whole-body MRI vs. 68Ga-PSMA PET/CT for staging of high-risk prostate cancer

Multiple myeloma: What is the most cost-effective imaging strategy for initial detection of bone lesions?

To determine the cost-effectiveness of different imaging modalities for initial detection of multiple myeloma (MM)-defining bone lesions. A Markov model from the health care system perspective for patients with MGUS was used to evaluate the incremental cost-effectiveness of five imaging techniques: skeletal survey (SS), low-dose computed tomography (LDCT), positron emission computed tomography (PETCT), and whole-body magnetic resonance imaging (WBMRI) with and without diffusion (DIFF). Model inputs, including probabilities, utilities, and costs were obtained from comprehensive literature review. Costs were estimated in 2024 U.S. dollars, effectiveness was measured in quality adjusted life years (QALYs), willingness-to-pay (WTP) threshold was set to $100,000/QALY, and timeframe of the simulation was 20years. Model analyses included Monte Carlo microsimulation and probabilistic sensitivity analysis (PSA). The most cost-effective imaging strategy was dependent on the number of patient risk factors for progression from MGUS to myeloma. At a WTP threshold of $100,000, for patients with no risk factors for progression, LDCT amassed the greatest net monetary benefit (NMB) ($1,030,913.57) while incurring the second lowest costs ($44,870.73). For patients with 1 or 2 risk factors for progression, WBMRI + DIFF amassed the greatest NMB (1 risk factor: $802,637.30, 2 risk factors: $664,430.36). WBMRI and PETCT were absolutely dominated in all cases. PSA also found that the most cost-effective strategy was dependent on the WTP threshold. Our model suggests that LDCT and WBMRI + DIFF can be the most cost-effective imaging strategies for the initial diagnosis of MM in patients, depending on the number of risk factors for progression.

The Effectiveness of Whole Body Magnetic Resonance Imaging Used in Health Screening Programs in Early Stage Cancer Diagnosis

Objective: We aim to present the findings and effectiveness of Whole Body Magnetic Resonance Imaging (WBMRI), which we use in the Health Screening Program (HSP) to diagnose cancer in early stage. Methods: This retrospective study was conducted between January 2017-February 2023. 393 individuals, between the ages of 18 and 85, who underwent WBMRI for HSP purposes, were included. The mean age was 50. Results: Malignancy suspicious lesions were observed in the head/neck region in 25 cases. Additional Magnetic Resonance (MRI) and Ultrasound (US) were performed. Mediastinal pathology was observed in 23 cases, and non-mediastinal thoracic pathologies were detected in 15. Therefore thorax Computed Tomography (CT), mammography, and breast US were performed. Benign lesions were observed in the liver in 44 cases, and US was performed. Malignancy-suspicious lesions in the liver were observed in 4, and dynamic abdominal MRI was performed. Cholelithiasis was observed in 16, and confirmed by US. The most common renal findings were; cysts and pelvicalyceal ectasia. Adrenal adenoma was observed in 5 cases. Two of the females had suspicion of gynecological malignancy. Massive diffuse concentric wall thickening was observed in the sigmoid colon, and colonoscopy was performed on one male. Musculoskeletal benign lesions were detected in 99 cases, and malignancy-suspicious lesions were detected in 35. Additional examinations such as US, CT, MRI, PET-CT, scintigraphy, and colonoscopy were performed on 172 cases. Malignancy was detected in 11 cases (2.8%). Conclusion: WBMRI is a radiation-free, non-invasive, short-term examination method. WBMRI is beneficial in diagnosing early-stage cancer.

The German National Cohort (NAKO): Current state and further follow-up data collection

Abstract The German National Cohort (NAKO) is a multidisciplinary, population-based cohort study that aims to investigate the development and aetiology of diseases, identify risk factors and enhance early detection and prevention of diseases. Between 2014 and 2019, a total of 205,415 subjects aged 20 -74 years were recruited and examined at 18 study centres across Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires, a wide range of biomedical examinations and the collection of various bio samples. Furthermore, whole-body magnetic resonance imaging (MRI) was performed on 30,861 participants at 5 of the18 study centres. The first re-examination of study participants started in October 2018, and will be completed end of July 2024 aiming for at least 135, 000 participants. Until April 2024 134,428 participants completed their second examination, including 18,707 participants with additional MRI examination. The second re-examination will start in May 2024 and will last until April 2028 aiming to examine at least 85,000 participants for a third time. Besides the examinations at the study centres, participants receive written health questionnaires (GEFUs) 2-3 years after their last examination to get additional information on incident diseases and changes in exposures. The first GEFU questionnaire (GEFU-1) was conducted between October 2017 and May 2023 and was filled in by 171,181 participants. Since the start of GEFU-2 in March 2023 65,624 participants have answered the GEFU-2 questionnaire. Due to the longitudinal design, the large sample size and the broad examination programme, NAKO provides information on determinants of population health and disease. Thus, it is a valuable resource for researchers from different disciplines.

Influence of gender and bruxism on the masseter muscle: A population-based magnetic resonance imaging study

This study aimed to (1) examine the cross-sectional area (CSA) of the masseter muscle in relation to bruxism and (2) investigate if there are gender-related differences in the masseter muscle in a population-based magnetic resonance imaging (MRI) study. The study included 720 subjects aged 30-89 years (391 women and 329 men) from the Study of Health in Pomerania, a cross-sectional population-based study assessing the prevalence and incidence of common population-relevant diseases and their risk factors in Northeastern Germany. The participants underwent both a whole-body MRI and a full oral examination. The CSAs of the masseter muscles on both sides were measured from MRI images. The presence or absence of awake and/or sleep grinding and clenching, unilateral chewing, and other parafunctional activities were obtained from the dental interview. Linear and ordinal logistic regression models were used to examine the associations between the CSAs of the masseter, bruxism, and gender. The frequency of bruxism and reports of muscle or joint pain were significantly higher in women. The analysis revealed that a larger masseter CSA was significantly associated with bruxism only in men. The larger CSA was manifested only in the higher frequency bruxers. Bruxism had heterogeneous effects on the masseter muscle between genders. Although a higher prevalence of bruxism was reported by women, the larger CSA of the masseter muscle was significantly higher in bruxing men but not in women. This study emphasizes the need for a gender-specific approach when evaluating the clinical implications of bruxism on the masseter muscle.

Three-Dimensional Magnetic Resonance Imaging in the Musculoskeletal System: Clinical Applications and Opportunities to Improve Imaging Speed and Resolution.

Although conventional 2-dimensional magnetic resonance (MR) sequences have traditionally comprised the foundational imaging strategy for visualization of musculoskeletal anatomy and pathology, the emergence of isotropic volumetric 3-dimensional sequences offers to advance musculoskeletal evaluation with comparatively similar image quality and diagnostic performance, shorter acquisition times, and the added advantages of improved spatial resolution and multiplanar reformation capability. The purpose of this review article is to summarize the available 3-dimensional MR sequences and their role in the management of patients with musculoskeletal disorders, including sports imaging, rheumatologic conditions, peripheral nerve imaging, bone and soft tissue tumor imaging, and whole-body MR imaging.

Soluble B-cell maturation antigen levels for disease monitoring in oligo- and non-secretory relapsed multiple myeloma

Soluble B-cell maturation antigen (sBCMA) is overexpressed on multiple myeloma (MM) cells. We investigated whether sBCMA levels correlated with other myeloma tumor volume indicators and its utility in monitoring oligo-secretory/non-secretory (O-S/Non-S) MM. In 115 patients with newly diagnosed MM, sBCMA was compared with M-protein levels, bone marrow plasma cells (BMPCs), circulating tumor cells (CTCs), and total diffusion volume (tDV; estimated by whole-body diffusion-weighted magnetic resonance imaging) at diagnosis. sBCMA levels increased significantly with International Staging System stage, chromosome 1q21 gain/amplification and CTC levels. sBCMA also correlated strongly with %BMPC (r = 0.65), moderately with tDV (r = 0.55) and paraprotein levels (involved immunoglobulin in IgG and IgA subtypes, r = 0.44 and 0.4; involved free light-chain levels in light-chain-only MM, r = 0.61, all P < 0.05). Longitudinal changes in sBCMA were consistent with disease status in both 17 O-S/Non-S and other secretory MM cases. Furthermore, sBCMA levels increased as early as 6 months pre-relapse in almost all O-S/Non-S relapsed patients. Thus, sBCMA correlates strongly with total tumor volume in MM, as assessed using different modalities. We suggest that sBCMA is useful, not only for monitoring responses in patients with O-S/Non-S MM but also for early relapse detection and prediction.

Whole body magnetic resonance imaging (WB MRI) in the diagnosis and evaluation of the effectiveness of treatment of metastatic prostate cancer: Met-RADS-P system standards

INTRODUCTION: Whole-body magnetic resonance imaging (WB MRI) including diffusion-weighted imaging (DWI) is increasingly used in clinical practice. For metastatic prostate cancer, the radiologic reporting and data system Met-RADS-P (METastasis Reporting and Data System for Prostate Cancer) has been proposed to determine the prevalence of the metastatic process and subsequently evaluate the response to specific treatment based on WB MRI data.OBJECTIVE: To present an overview of the methodological aspects of WB MRI in patients with metastatic prostate cancer in relation to the Met-RADS-P system, to outline its terminology and principles for assessing study results, and to discuss the possibilities of its clinical use.MATERIALS AND METHODS: A search was conducted for publications for the period from January 1, 2017 to December 1, 2023 in Russian and English in the electronic databases eLibrary, Medline, PubMed, using the keywords: «диффузионно-взвешенная томография всего тела», «метастатический рак предстательной железы», «Met-RADS-P», «Whole Body MRI, WB MRI», «Whole Body DWI, WB DWI», «metastatic prostate cancer», supplemented by examination of references in the retrieved articles.RESULTS: Based on the literature data and our own experience, WB MRI protocols in patients with metastatic prostate cancer are described, the algorithm of MR image analysis, the criteria for evaluating the response of metastatic foci in the skeleton, lymph nodes, and internal organs, and the response assessment categories according to the RAC (response assessment categories) scale, as well as summarize the results and discuss the prospects for the clinical use of Met-RADS-P.DISCUSSION: The few publications in the literature using the Met-RADS-P system primarily concern the assessment of its reliability (inter-reader agreement). The authors conclude that it is appropriate to use it in monitoring metastases in patients with castration-resistant prostate cancer, emphasizing the clinical importance of identifying discordant responses after therapy. They also note the obstacles to the widespread introduction of WB MRI imaging into clinical practice, including the duration of the examination procedure and the large volume of diagnostic data that requires significant time for analysis and reporting, which can be overcome by automating the assessment of MR images using artificial intelligence.CONCLUSION: The Met-RADS-P system systematizes the approach to performing and describing WB MRI in patients with advanced prostate cancer, allowing the technique to be reproduced on virtually any modern scanner, from the scan protocol to a standardized report of findings. This makes the WB MRI technique reproducible in a variety of medical settings, and therefore increases its value. Nevertheless, Met-RADS-P is a relatively new system and requires large multicenter clinical trials to confirm its efficacy and representativeness, as well as to level out its shortcomings.

Whole-body non-forensic fetal virtopsy using postmortem magnetic resonance imaging at 7 Tesla vs classical autopsy.

To determine the diagnostic accuracy of virtual autopsy using whole-body postmortem ultra-high field magnetic resonance imaging (MRI) at 7 Tesla (T), using a short T2-weighted imaging (T2-WI) protocol, compared with classical autopsy, for detecting structural abnormalities in small second-trimester fetuses. Thirty consecutive fetuses at 13-19 weeks' gestation (weight, 17-364 g) were included following spontaneous pregnancy loss or termination of pregnancy. After fixation in 10% formaldehyde solution (48 h to 1 week), all fetuses were scanned using a two-dimensional turbo high-resolution T2-WI protocol with multislice relaxation time, followed by an invasive autopsy. The diagnostic accuracy of virtual autopsy vs classical autopsy was calculated for 990 anatomical structures (30 fetuses × 33 items). Sensitivity, specificity, positive and negative predictive values and Cohen's κ coefficient of agreement, with their 95% CIs, as well as the McNemar test, were used to evaluate the accuracy and agreement of the two diagnostic methods. Analysis was stratified by anatomical segment (nervous, pulmonary, cardiovascular, digestive, renal, facial and skeletal) and across three gestational-age intervals (13-14, 15-16 and 17-19 weeks). Considering classical autopsy as the gold standard, virtual autopsy had a sensitivity of 92.04% (95% CI, 85.42-96.29%) and a specificity of 97.87% (95% CI, 94.64-99.42%), with a positive predictive value of 96.30% (95% CI, 90.78-98.56%) and a negative predictive value of 95.34% (95% CI, 91.61-97.45%), achieving a diagnostic accuracy of 95.68% (95% CI, 92.73-97.68%) for detecting structural abnormalities in second-trimester fetuses. Cohen's κ for virtual vs classical autopsy was 0.907. The diagnostic ability of virtual autopsy at 7 T for malformed fetuses was superior to that of classical autopsy for analyzing the nervous system in small fetuses with pronounced autolysis, equivalent to that of classical autopsy when analyzing pulmonary, cardiovascular and renal systems and inferior when evaluating the fetal intestines. The sensitivity of virtual autopsy at 7 T for describing structural abnormalities increased with gestational age. Virtual fetal autopsy using 7-T MRI and a turbo high-resolution T2-WI protocol with multislice relaxation time is a feasible postmortem diagnostic tool for the identification of fetal structural anomalies. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

6483 Diaphyseal Medullary Stenosis With Malignant Fibrous Histiocytoma: A Rare Skeletal Dysplasia/Sarcoma Syndrome

Abstract Disclosure: A. Grover: None. C.R. Ferreira: None. R.I. Gafni: None. S. Jumani: None. M.T. Collins: None. K.L. Roszko: None. I.R. Hartley: None. Introduction: Diaphyseal medullary stenosis with malignant fibrous histiocytoma (DMS-MFH) is a rare autosomal dominant syndrome associated with pathologic fractures, myopathy, premature hair graying, and aggressive osteosarcomas. DMS-MFH has been linked to genetic variants in the methylthioadenosine phosphorylase (MTAP) gene, which encodes an enzyme in the methionine salvage and polyamine synthesis pathway. This pathway is implicated in other skeletal fragility disorders, such as Snyder-Robinson syndrome, suggesting a still undefined role of this pathway in bone biology. We describe a kindred with DMS-MFH and identify diagnostic challenges. Case: A 53-year-old perimenopausal woman presented with four fragility fractures over one year. Relevant history included premature hair graying, esophageal strictures, and nephrolithiasis. The patient’s bone formation markers were slightly elevated; bone resorption markers were within reference range. Her only osteoporosis risk factor was perimenopausal status. Bone series showed a diffuse heterogeneous appearance of the long bones with a mixed lytic/sclerotic appearance. DEXA scan revealed osteopenia. Family history was significant for 2 sons with aggressive osteosarcomas diagnosed in their late teens; one died at age 20. The other son is currently 39-years-old with recurrent osteosarcomas in three different limbs. The family also has a multigenerational history of severe bone fragility, muscle weakness, and premature hair graying. The patient, her living son, and his father underwent genome sequencing that identified a variant in MTAP (c.885A&amp;gt;G; p.(R295=)) in the patient and son. This variant was previously reported in three other families with DMS-MFH and has been shown to alter splicing. Notably, commercial genetic testing did not report this as a relevant variant, and diagnosis required independent analysis of the raw sequence data. Based on these findings, the patient and her son were diagnosed with DMS-MFH. Given the bone fragility with elevated bone turnover markers we treated the patient with yearly zoledronic acid infusions with no subsequent fractures. Surveillance for osteosarcoma is also being performed with annual whole-body MRI. Conclusion: DMS-MFH has been reported in only five families to date. The sixth family described here has clinical characteristics similar to the other kindreds. Due to high risk of aggressive osteosarcoma, timely diagnosis is imperative to decrease morbidity and mortality. Commercial genome sequencing may miss this diagnosis, so targeted genetic testing should be pursued. As more cases are identified, characterization of affected families may enhance our understanding of the natural history of the disease and guide surveillance and treatment strategies. Presentation: 6/2/2024

Development and evaluation of machine-learning methods in whole-body magnetic resonance imaging with diffusion weighted imaging for staging of patients with cancer: the MALIBO diagnostic test accuracy study

Background Whole-body magnetic resonance imaging is accurate, efficient and cost-effective for cancer staging. Machine learning may support radiologists reading whole-body magnetic resonance imaging. Objectives To develop a machine-learning algorithm to detect normal organs and cancer lesions. To compare diagnostic accuracy, time and agreement of radiology reads to detect metastases using whole-body magnetic resonance imaging with concurrent machine learning (whole-body magnetic resonance imaging + machine learning) against standard whole-body magnetic resonance imaging (whole-body magnetic resonance imaging + standard deviation). Design and participants Retrospective analysis of (1) prospective single-centre study in healthy volunteers &gt; 18 years (n = 51) and (2) prospective multicentre STREAMLINE study patient data (n = 438). Tests Index: whole-body magnetic resonance imaging + machine learning. Comparator: whole-body magnetic resonance imaging + standard deviation. Reference standard Previously established expert panel consensus reference at 12 months from diagnosis. Outcome measures Primary: difference in per-patient specificity between whole-body magnetic resonance imaging + machine learning and whole-body magnetic resonance imaging + standard deviation. Secondary: per-patient sensitivity, per-lesion sensitivity and specificity, read time and agreement. Methods Phase 1: classification forests, convolutional neural networks, and a multi-atlas approaches for organ segmentation. Phase 2/3: whole-body magnetic resonance imaging scans were allocated to Phase 2 (training = 226, validation = 45) and Phase 3 (testing = 193). Disease sites were manually labelled. The final algorithm was applied to 193 Phase 3 cases, generating probability heatmaps. Twenty-five radiologists (18 experienced, 7 inexperienced in whole-body magnetic resonance imaging) were randomly allocated whole-body magnetic resonance imaging + machine learning or whole-body magnetic resonance imaging + standard deviation over two or three rounds in a National Health Service setting. Read time was independently recorded. Results Phases 1 and 2: convolutional neural network had best Dice similarity coefficient, recall and precision measurements for healthy organ segmentation. Final algorithm used a ‘two-stage’ initial organ identification followed by lesion detection. Phase 3: evaluable scans (188/193, of which 50 had metastases from 117 colon, 71 lung cancer cases) were read between November 2019 and March 2020. For experienced readers, per-patient specificity for detection of metastases was 86.2% (whole-body magnetic resonance imaging + machine learning) and 87.7% (whole-body magnetic resonance imaging + standard deviation), (difference −1.5%, 95% confidence interval −6.4% to 3.5%; p = 0.387); per-patient sensitivity was 66.0% (whole-body magnetic resonance imaging + machine learning) and 70.0% (whole-body magnetic resonance imaging + standard deviation) (difference −4.0%, 95% confidence interval −13.5% to 5.5%; p = 0.344). For inexperienced readers (53 reads, 15 with metastases), per-patient specificity was 76.3% in both groups with sensitivities of 73.3% (whole-body magnetic resonance imaging + machine learning) and 60.0% (whole-body magnetic resonance imaging + standard deviation). Per-site specificity remained high within all sites; above 95% (experienced) or 90% (inexperienced). Per-site sensitivity was highly variable due to low number of lesions in each site. Reading time lowered under machine learning by 6.2% (95% confidence interval −22.8% to 10.0%). Read time was primarily influenced by read round with round 2 read times reduced by 32% (95% confidence interval 20.8% to 42.8%) overall with subsequent regression analysis showing a significant effect (p = 0.0281) by using machine learning in round 2 estimated as 286 seconds (or 11%) quicker. Interobserver variance for experienced readers suggests moderate agreement, Cohen’s κ = 0.64, 95% confidence interval 0.47 to 0.81 (whole-body magnetic resonance imaging + machine learning) and Cohen’s κ = 0.66, 95% confidence interval 0.47 to 0.81 (whole-body magnetic resonance imaging + standard deviation). Limitations Patient whole-body magnetic resonance imaging data were heterogeneous with relatively few metastatic lesions in a wide variety of locations, making training and testing difficult and hampering evaluation of sensitivity. Conclusions There was no difference in diagnostic accuracy for whole-body magnetic resonance imaging radiology reads with or without machine-learning support, although radiology read time may be slightly shortened using whole-body magnetic resonance imaging + machine learning. Future work Failure-case analysis to improve model training, automate lesion segmentation and transfer of machine-learning techniques to other tumour types and imaging modalities. Study registration This study is registered as ISRCTN23068310. Funding This award was funded by the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation (EME) programme (NIHR award ref: 13/122/01) and is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 15. See the NIHR Funding and Awards website for further award information.

Clinical impact of whole-body MRI in staging and surveillance of patients with myxoid liposarcoma: a 14-year single-centre retrospective study.

To assess the clinical impact of regular whole-body magnetic resonance imaging (WBMRI) surveillance in myxoid liposarcoma patients. This was a retrospective cohort study of myxoid liposarcoma patients who underwent at least one WBMRI at our institution between October 2006 and December 2020. The effect of WBMRI on clinical management, namely treatment modification or additional diagnostic investigations was studied. A standardised WBMRI surveillance protocol was instituted in 2015. We compared patient outcomes for the metastatic patients who had and had not received regular WBMRI surveillance and performed survival analysis for both subgroups. Of the 56 patients (60.7% male, median age: 48.1 years) who underwent 345 WBMRI, 17 (30.3%) had metastases, and 168 WBMRI were performed in this group. The median imaging follow-up for the entire cohort was 35 months; the metastatic group had a median follow-up of 42 months. WBMRI changed the clinical management in 13 (76.5%) metastatic patients, with 33 instances of treatment modification. Thirty-five lesions were labelled 'indeterminate,' 16 (45.7%) had additional investigations/interventions, and 4 (11.4%) were confirmed to be metastatic. Twenty-one metastatic lesions were missed initially on WBMRI and confirmed on subsequent WBMRI, of which 5 (23.8%) were clinically significant. The 5-year survival since the detection of metastasis was better in the regular surveillance subgroup (85.7% vs. 45%), but this was not statistically significant (p = 0.068). Five patients (8.9%) developed their first metastasis more than 5 years after diagnosing the primary lesion. Regular WBMRI surveillance of myxoid liposarcoma patients considerably impacts clinical management by frequently influencing treatment decisions. WBMRI has been recently recommended as an imaging option for the staging and surveillance of myxoid liposarcoma patients. Our study highlights the impact of regular WBMRI surveillance on the clinical management of these patients and how it affects their survival.