Undifferentiated round cell sarcoma with CRTC1::SS18 fusion: Expanding clinicopathologic features of a rare translocation sarcoma with prominent desmoplastic stroma.

Undifferentiated round cell sarcomas (URCS) represent a diverse group of tumors, including conventional Ewing sarcoma, round cell sarcoma with EWSR1/FUS-non-ETS fusions, CIC-rearranged sarcoma, and sarcoma with BCOR alterations. Since 2018, three cases of URCS with a novel CRTC1::SS18 gene fusion have been reported in the literature. Herein, we report three additional cases of CRTC1::SS18 sarcoma, thereby doubling the number of described cases and expanding the clinicopathologic features of this rare translocation sarcoma. Together with the previously reported cases, we show that the male-to-female ratio is 1:2 with a median age of 34 years (range: 12 to 42 years). Tumors occurred primarily in intramuscular locations involving the lower extremity. Histologically, all tumors contained uniform round to epithelioid cells with a moderate amount of eosinophilic cytoplasm growing in sheets and nests with prominent desmoplastic stroma reminiscent of desmoplastic small round cell tumor (DSRCT). Immunohistochemical results were non-specific, demonstrating variable expression of CD99 (patchy), ALK, GATA3, and cyclin D1. RNA sequencing revealed CRTC1::SS18 gene fusions in all cases, involving exon 1-2 of CRTC1 (the 5' partner gene) on chromosome 19 and either exon 2 or exon 4 of SS18 (the 3' partner gene) on chromosome 18. The clinical course was variable. While one previously reported case demonstrated aggressive behavior with fatal outcome, two others had a relatively indolent course with gradual growth for 6-7 years prior to resection. Two cases developed metastatic disease, including one case with bilateral lung metastasis and one with locoregional spread to a lymph node. By analyzing the clinicopathologic features, we aim to improve recognition of this rare translocation sarcoma to better understand its biologic potential, optimize patient management, and expand the current classification of URCS.

Magnetic Resonance Imaging Biomarkers of Bone and Soft Tissue Tumors.

Magnetic resonance imaging (MRI) is essential in the management of musculoskeletal (MSK) tumors. This review delves into the diverse MRI modalities, focusing on anatomical, functional, and metabolic sequences that provide essential biomarkers for tumor detection, characterization, disease extent determination, and assessment of treatment response. MRI's multimodal capabilities offer a range of biomarkers that enhance MSK tumor evaluation, aiding in better patient management.

MRI features of benign peripheral nerve sheath tumors: how do sporadic and syndromic tumors differ?

OBJECTIVES: To compare MRI features of sporadic and neurofibromatosis syndrome-related localized schwannomas and neurofibromas. METHODS: In this retrospective study, our pathology database was searched for "neurofibroma" or "schwannoma" from 2014 to 2019. Exclusion criteria were lack of available MRI and intradural or plexiform tumors. Qualitative and quantitative anatomic (location, size, relationship to nerve, signal, muscle denervation) and functional (arterial enhancement, apparent diffusion-weighted coefficient) MRI features of sporadic and syndrome-related tumors were compared. Statistical significance was assumed for p < 0.05. RESULTS: A total of 80 patients with 64 schwannomas (sporadic: 42 (65.6%) v. syndrome-related: 22 (34.4%)) and 19 neurofibromas (sporadic: 7 (36.8%) v. syndrome-related: 12 (41.7%)) were included. Only signal heterogeneity (T2W p=0.001, post-contrast p=0.03) and a diffused-weighted imaging target sign (p=0.04) were more frequent with schwannomas than neurofibromas. Sporadic schwannomas were similar in size to syndrome-related schwannomas (2.9±1.2cm vs. 3.7±3.2 cm, p = 0.6), but with greater heterogeneity (T2W p = 0.02, post-contrast p = 0.01). Sporadic neurofibromas were larger (4.6±1.5cm vs. 3.4±2.4 cm, p = 0.03) than syndrome-related neurofibromas, also with greater heterogeneity (T2W p=0.03, post-contrast p=0.04). Additional tumors along an affected nerve were only observed with syndrome-related tumors). There was no difference in apparent diffusion coefficient values or presence of early perfusion between sporadic and syndrome-related tumors (p > 0.05). CONCLUSIONS: Although syndrome-related and sporadic schwannomas and neurofibromas overlap in their anatomic, diffusion and perfusion features, signal heterogeneity and presence of multiple lesions along a nerve are differentiating characteristics of syndrome-related tumors.

Bone tumors: state-of-the-art imaging.

Imaging plays a central role in the management of patients with bone tumors. A number of imaging modalities are available, with different techniques having unique applications that render their use advantageous for various clinical purposes. Coupled with detailed clinical assessment, radiological imaging can assist clinicians in reaching a proper diagnosis, determining appropriate management, evaluating response to treatment, and monitoring for tumor recurrence. Although radiography is still the initial imaging test of choice for a patient presenting with a suspected bone tumor, technological innovations in the last decades have advanced the role of other imaging modalities for assessing bone tumors, including advances in computed tomography, magnetic resonance imaging, scintigraphy, and hybrid imaging techniques that combine two existing modalities, providing clinicians with diverse tools for bone tumor imaging applications. Determining the most suitable modality to use for a particular application requires familiarity with the modality in question, its advancements, and its limitations. This review highlights the various imaging techniques currently available and emphasizes the latest developments in imaging, offering a framework that can help guide the imaging of patients with bone tumors.

Nodular cystic fat necrosis: a distinctive rare soft-tissue mass.

We report the case of a 34-year-old female who was evaluated for a right lower extremity soft-tissue mass, found to be a large cystic lesion bound by fibrous tissue containing innumerable, freely mobile nodules of fat. Her presentation suggested the diagnosis of nodular cystic fat necrosis (NCFN), a rare entity that likely represents a morphological subset of fat necrosis potentially caused by vascular insufficiency secondary to local trauma. Her lesion was best visualized using MRI, which revealed characteristic imaging features of NCFN including nodular lipid-signal foci that suppress on fat-saturated sequences, intralesional fluid with high signal intensity on T2-weighted imaging, and a contrast-enhancing outer capsule with low signal intensity on T1-weighted imaging. Ultrasound imaging offered the advantage of showing mobile hyperechogenic foci within the anechoic cystic structure, and the lesion was otherwise visualized on radiography as a nonspecific soft-tissue radiopacity. She was managed with complete surgical excision with pathologic evaluation demonstrating, similar to the radiologic features, innumerable free-floating, 1-5 mm, smooth, nearly uniform spherical nodules of mature fat with widespread necrosis contained within a thick fibrous pseudocapsule. Follow-up imaging revealed no evidence of remaining or recurrent disease on postoperative follow-up MRI. The differential diagnosis includes lipoma with fat necrosis, lipoma variant, atypical lipomatous tumor, and a Morel-Lavallée lesion. There is overlap in the imaging features between fat necrosis and both benign and malignant adipocytic tumors, occasionally making this distinction based solely on imaging findings challenging. To our knowledge, this is the largest example of NCFN ever reported.

The role of imaging in extremity sarcoma surgery.

The surgical management of extremity bone and soft tissue sarcomas has evolved significantly over the last 50 years. The introduction and refinement of high-resolution cross-sectional imaging has allowed accurate assessment of anatomy and tumor extent, and in the current era more than 90% of patients can successfully undergo limb-salvage surgery. Advances in imaging have also revolutionized the clinician's ability to assess treatment response, detect metastatic disease, and perform intraoperative surgical navigation. This review summarizes the broad and essential role radiology plays in caring for sarcoma patients from diagnosis to post-treatment surveillance. Present evidence-based imaging paradigms are highlighted along with key future directions.

Multidisciplinary neurofibromatosis conference in the management of patients with neurofibromatosis type 1 and schwannomatosis in a single tertiary care institution.

OBJECTIVE: To evaluate the role of weekly neurofibromatosis (NF) multi-disciplinary conferences (MDC) on the diagnostic and therapeutic plan for patients with NF type 1 (NF1) and schwannomatosis (SWN). MATERIALS AND METHODS: This retrospective study reviewed patients with confirmed or suspected NF1 and SWN discussed in weekly MDC from March to July 2021. Demographic data collected included patient age, sex, pre-conference and post-conference diagnosis, radiological studies reviewed, and provider specialties in attendance. Outcomes reported included changes in imaging interpretation and treatment plans, changes in post-conference diagnosis relative to pre-conference diagnosis, and time to completion of the recommended change in treatment. RESULTS: Data from 17 MDC "pre-conference" lists included 75 patients (38 female, 37 males, mean age (years): 38 (range: 6-80)) with NF1 (52%, 39/75) and SWN (36%, 27/75) discussed over a total of 91 case reviews. 18.7% (14/75) of all patients had NF2-related SWN, and 17.3% (13/75) of all patients had non-NF2 SWN. The MDC led to changes in imaging interpretation in 18.7% and changes in patient management in 74.7% (diagnostic testing (n = 52), surgical plan (n = 24), medical treatment (n = 9), clinical trial status (n = 4), and radiation treatment (n = 1)) of cases. Among patients for whom a change in management was recorded, 91% (62/68) completed at least one recommendation (mean time to completion (days): 41.4 (range: 0-278)). CONCLUSION: Weekly MDC changes the diagnostic and therapeutic management of the majority of patients discussed (74.7%) and promotes a high adherence rate to recommendations (91%).

Clinical Applications and Controversies of Whole-Body MRI: AJR Expert Panel Narrative Review.

Whole-body MRI (WB-MRI) is increasing in clinical acceptance and utilization for a range of indications. WB-MRI is currently an established screening tool for children and adults at high risk of developing malignancy, with the strongest supporting evidence in patients with Li-Fraumeni syndrome. WB-MRI has been added to professional society guidelines for staging disease in patients with certain malignancies including multiple myeloma and has been proposed as a technique to screen for metastatic disease in patients with visceral malignancies including prostate cancer and breast cancer. Emerging data support the utility of WB-MRI in children with malignancies such as Ewing sarcoma, in adults with myxoid liposarcoma, and in pregnant patients with occult or newly detected malignancy. WB-MRI can further help evaluate disease extent and treatment response in patients with nononcologic conditions such as chronic nonbacterial osteomyelitis, myopathy, inflammatory arthritis, and fever of unknown origin. This AJR Expert Panel Narrative Review summarizes available evidence and recommendations supporting the clinical applications of WB-MRI. This article also highlights limitations, barriers, and controversies associated with utilization of WB-MRI in routine clinical practice.

Recurrent chondromyxoid fibroma of the distal femur treated with percutaneous cryoablation.

Chondromyxoid fibroma is a rare, benign tumor of the bone with excellent prognosis but a high rate of recurrence. We report a patient presenting with pain and a history of chondromyxoid fibroma of the distal left femur previously treated with multiple prior curettage and bone graft procedures. Magnetic resonance imaging and histopathology indicated a recurrence of tumor. Due to the small size of the tumor recurrence and challenges associated with prior open surgery, the patient underwent cryoablation of the lesion with computed tomography guidance. Follow-up 18 months later indicated a resolution of pain and improvement on magnetic resonance imaging, and no concerns after 20 months. To our knowledge, this is the first reported case of chondromyxoid fibroma treated with cryoablation. This case suggests cryoablation could be considered in the setting of recurrent chondromyxoid fibroma for local tumor control.

Prevalence of avascular necrosis in idiopathic inflammatory myopathies: a single-centre experience.

OBJECTIVES: To assess the prevalence of avascular necrosis (AVN) in a large cohort of patients with idiopathic inflammatory myopathies (IIM) and define the major associated risk factors. METHODS: We retrospectively reviewed the electronic medical records of all patients with a definitive diagnosis of IIM enrolled in our registry between 2003 and 2017, and followed until 2020. Pertinent demographic, clinical, serologic and imaging data were collected. A matched group of patients without AVN was then selected for comparison. RESULTS: A total of 1680 patients were diagnosed with IIM. Fifty-one patients developed AVN, with an overall prevalence of 3%. Musculoskeletal MRI was available for 1085 patients and AVN was present in 46 patients (43 lower extremities and 3 upper extremities MRI studies), with a relative prevalence of 4.2%. Most patients with AVN were Caucasian females (57%) with a mean (s.d.) age at diagnosis of 44.5 (12.4) years. Sixty-one percent had DM and 29% had PM. The median time from onset of IIM to diagnosis of AVN was 46 months. The hip joint was most commonly involved in 76% of cases, followed by the knee joint in 15% and shoulder joint in 9%. Some 81% of patients were asymptomatic. Established risk factors for AVN were not found to be associated with the development of AVN in IIM patients. CONCLUSION: Although mostly asymptomatic and incidental, the overall prevalence of AVN in IIM was 3% and the prevalence by MRI was 4.2%. None of the established risk factors was found to be associated with AVN development.

MRI evaluation of soft tissue tumors: comparison of a fast, isotropic, 3D T2-weighted fat-saturated sequence with a conventional 2D T2-weighted fat-saturated sequence for tumor characteristics, resolution, and acquisition time.

OBJECTIVES: To test whether a 4-fold accelerated 3D T2-weighted (T2) CAIPIRINHA SPACE TSE sequence with isotropic voxel size is equivalent to conventional 2DT2 TSE for the evaluation of intrinsic and perilesional soft tissue tumors (STT) characteristics. METHODS: For 108 patients with histologically-proven STTs, MRI, including 3DT2 (CAIPIRINHA SPACE TSE) and 2DT2 (TSE) sequences, was performed. Two radiologists evaluated each sequence for quality (diagnostic, non-diagnostic), tumor characteristics (heterogeneity, signal intensity, margin), and the presence or absence of cortical involvement, marrow edema, and perilesional edema (PLE); tumor size and PLE extent were measured. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios and acquisition times for 2DT2 in two planes and 3DT2 sequences were reported. Descriptive statistics and inter-method agreement were reported. RESULTS: Image quality was diagnostic for all sequences (100% [108/108]). No difference was observed between 3DT2 and 2DT2 tumor characteristics (p < 0.05). There was no difference in mean tumor size (3DT2: 2.9 ± 2.5 cm, 2DT2: 2.8 ± 2.6 cm, p = 0.4) or PLE extent (3DT2:0.5 ± 1.2 cm, 2DT2:0.5 ± 1.0 cm, p = 0.9) between the sequences. There was no difference in the SNR of tumors, marrow, and fat between the sequences, whereas the SNR of muscle was higher (p < 0.05) on 3DT2 than 2DT2. CNR measures on 3DT2 were similar to 2DT2 (p > 0.1). The average acquisition time was shorter for 3DT2 compared with 2DT2 (343 ± 127 s vs 475 ± 162 s, respectively). CONCLUSION: Isotropic 3DT2 MRI offers higher spatial resolution, faster acquisition times, and equivalent assessments of STT characteristics compared to conventional 2DT2 MRI in two planes. 3DT2 is interchangeable with a 2DT2 sequence in tumor protocols. KEY POINTS: • Isotropic 3DT2 CAIPIRINHA SPACE TSE offers higher spatial resolution than 2DT2 TSE and is equivalent to 2DT2 TSE for assessments of soft tissue tumor intrinsic and perilesional characteristics. • Multiplanar reformats of 3DT2 CAIPIRINHA SPACE TSE can substitute for 2DT2 TSE acquired in multiple planes, thereby reducing the acquisition time of MRI tumor protocols. • 3DT2 CAIPIRINHA SPACE TSE and 2DT2 TSE had similar CNR of tissues.

Neuropathy Score Reporting and Data System: A Reporting Guideline for MRI of Peripheral Neuropathy With a Multicenter Validation Study.

BACKGROUND. A standardized guideline and scoring system would improve evaluation and reporting of peripheral neuropathy (PN) on MRI. OBJECTIVE. The objective of this study was to create and validate a neuropathy classification and grading system, which we named the Neuropathy Score Reporting and Data System (NS-RADS). METHODS. This retrospective study included 100 patients with nerve imaging studies and known clinical diagnoses. Experts crafted NS-RADS using mutually agreed-on qualitative criteria for the classification and grading of PN. Different classes were created to account for the spectrum of underlying pathologies: unremarkable (U), injury (I), neoplasia (N), entrapment (E), diffuse neuropathy (D), not otherwise specified (NOS), and postintervention state (PI). Subclasses were established to describe the severity or extent of the lesions. Validation testing was performed by 11 readers from 10 institutions with experience levels ranging from 3 to 18 years after residency. After initial reader training, cases were presented to readers who were blinded to the final clinical diagnoses. Interobserver agreement was assessed using correlation coefficients and the Conger kappa, and accuracy testing was performed. RESULTS. Final clinical diagnoses included normal (n = 5), nerve injury (n = 25), entrapment (n = 15), neoplasia (n = 33), diffuse neuropathy (n = 18), and persistent neuropathy after intervention (n = 4). The miscategorization rate for NS-RADS classes was 1.8%. Final diagnoses were correctly identified by readers in 71-88% of cases. Excellent inter-reader agreement was found on the NS-RADS pathology categorization (κ = 0.96; 95% CI, 0.93-0.98) as well as muscle pathology categorization (κ = 0.76; 95% CI, 0.68-0.82). The accuracy for determining milder versus more severe categories per radiologist ranged from 88% to 97% for nerve lesions and from 86% to 94% for muscle abnormalities. CONCLUSION. The proposed NS-RADS classification is accurate and reliable across different reader experience levels and a spectrum of PN conditions. CLINICAL IMPACT. NS-RADS can be used as a standardized guideline for reporting PN and improved multidisciplinary communications.

Selective MR neurography-guided anterior femoral cutaneous nerve blocks for diagnosing anterior thigh neuralgia: anatomy, technique, diagnostic performance, and patient-reported experiences.

OBJECTIVE: To evaluate the clinical utility of selective magnetic resonance neurography-(MRN)-guided anterior femoral cutaneous nerve (AFCN) blocks for diagnosing anterior thigh neuralgia. MATERIALS AND METHODS: Following institutional review board approval and informed consent, participants with intractable anterior thigh pain and clinically suspected AFCN neuralgia were included. AFCN blocks were performed under MRN guidance using an anterior groin approach along the medial sartorius muscle margin. Outcome variables included AFCN identification on MRN, technical success of perineural drug delivery, rate of AFCN anesthesia, complications, total procedure time, patient-reported procedural experiences, rate of positive diagnostic AFCN blocks, and positive subsequent treatment rate. RESULTS: Eighteen MRN-guided AFCN blocks (six unilateral and six bilateral blocks) were performed in 12 participants (6 women; age, 49 (30-65) years). Successful MRN identified the AFCN, successful perineural drug delivery, and AFCN anesthesia was achieved in all thighs. No complications occurred. The total procedure time was 19 (10-28) min. Patient satisfaction and experience were high without adverse MRI effects. AFCN blocks identified the AFCN as the symptom generator in 16/18 (89%) cases, followed by 14/16 (88%) successful treatments. CONCLUSION: Our results suggest that selective MR neurography-guided AFCN blocks effectively diagnose anterior femoral cutaneous neuralgia and are well-tolerated.

Neuropathy Score Reporting and Data System (NS-RADS): MRI Reporting Guideline of Peripheral Neuropathy Explained and Reviewed.

A standardized guideline and scoring system should be used for the MR imaging diagnosis of peripheral neuropathy. The MR imaging-based Neuropathy Score Reporting and Data System (NS-RADS) is a newly devised classification system (in press in AJR) that can be used to communicate both type and severity of peripheral neuropathy in the light of clinical history and examination findings. The spectrum of neuropathic conditions and peripheral nerve disorders covered in this system includes nerve injury, entrapment, neoplasm, diffuse neuropathy, and post-interventional states. This classification system also describes the temporal MR imaging appearances of regional muscle denervation changes. This review article is based on the multicenter validation study pre-published in American journal of Roentgenology and discusses technical considerations of optimal MR imaging for peripheral nerve evaluation and discusses the NS-RADS classification and its severity scales with illustration of conditions that fall under each classification. The readers can gain knowledge of the NS-RADS classification system and learn to apply it in their practices for improved inter-disciplinary communications and timely patient management.

Society of Skeletal Radiology- white paper. Guidelines for the diagnostic management of incidental solitary bone lesions on CT and MRI in adults: bone reporting and data system (Bone-RADS).

The purpose of this article is to present algorithms for the diagnostic management of solitary bone lesions incidentally encountered on computed tomography (CT) and magnetic resonance (MRI) in adults. Based on review of the current literature and expert opinion, the Practice Guidelines and Technical Standards Committee of the Society of Skeletal Radiology (SSR) proposes a bone reporting and data system (Bone-RADS) for incidentally encountered solitary bone lesions on CT and MRI with four possible diagnostic management recommendations (Bone-RADS1, leave alone; Bone-RADS2, perform different imaging modality; Bone-RADS3, perform follow-up imaging; Bone-RADS4, biopsy and/or oncologic referral). Two algorithms for CT based on lesion density (lucent or sclerotic/mixed) and two for MRI allow the user to arrive at a specific Bone-RADS management recommendation. Representative cases are provided to illustrate the usability of the algorithms.

Do contrast-enhanced and advanced MRI sequences improve diagnostic accuracy for indeterminate lipomatous tumors?

PURPOSE: Benign, intermediate-grade and malignant tumors sometimes have overlapping imaging and clinical characteristics. The purpose of this study was to evaluate the added value of contrast-enhanced sequences (dynamic contrast enhancement (DCE)), diffusion-weighted imaging (DWI), and chemical shift imaging (CSI) to noncontrast MRI sequences for the characterization of indeterminate lipomatous tumors. MATERIALS AND METHODS: Thirty-two consecutive patients with histologically proven peripheral lipomatous tumors were retrospectively evaluated. Two musculoskeletal radiologists recorded the MRI features in three sessions: (1) with noncontrast T1-weighted and fluid-sensitive sequences; (2) with addition of static pre- and post-contrast 3D volumetric T1-weighted sequences; and (3) with addition of DCE, DWI, and CSI. After each session, readers recorded a diagnosis (benign, intermediate/atypical lipomatous tumor (ALT), or malignant/dedifferentiated liposarcoma (DDL)). Categorical imaging features (presence of septations, nodules, contrast enhancement) and quantitative metrics (apparent diffusion coefficient values, CSI signal loss) were recorded. RESULTS: For 32 tumors, the diagnostic accuracy of both readers did not improve with the addition of contrast-enhanced sequences, DWI, or CSI (53% (17/32) session 1; 50% (16/30) session 2; 53% (17/32) session 3). Noncontrast features, including thick septations (p = 0.025) and nodules ≥ 1 cm (p < 0.001), were useful for differentiating benign tumors from ALTs and DDLs, as were DWI (p = 0.01) and CSI (p = 0.009) metrics. CONCLUSION: The addition of contrast-enhanced sequences (static, DCE), DWI, and CSI to a conventional, noncontrast MRI protocol did not improve diagnostic accuracy for differentiating benign, intermediate-grade, and malignant lipomatous tumors. However, we identified potentially useful imaging features by DCE, DWI, and CSI that may help distinguish these entities.

Imaging Review of Peripheral Nerve Injuries in Patients with COVID-19.

With surging numbers of patients with coronavirus disease 2019 (COVID-19) throughout the world, neuromuscular complications and rehabilitation concerns are becoming more apparent. Peripheral nerve injury can occur in patients with COVID-19 secondary to postinfectious inflammatory neuropathy, prone positioning-related stretch and/or compression injury, systemic neuropathy, or nerve entrapment from hematoma. Imaging of peripheral nerves in patients with COVID-19 may help to characterize nerve abnormality, to identify site and severity of nerve damage, and to potentially elucidate mechanisms of injury, thereby aiding the medical diagnosis and decision-making process. This review article aims to provide a first comprehensive summary of the current knowledge of COVID-19 and peripheral nerve imaging.

The Role of Whole-Body MRI in Pediatric Musculoskeletal Oncology: Current Concepts and Clinical Applications.

Whole-body magnetic resonance imaging (WB-MRI) has gained importance in the field of musculoskeletal oncology over the last decades, consisting in a one-stop imaging method that allows a wide coverage assessment of both bone and soft tissue involvement. WB-MRI is valuable for diagnosis, staging, and follow-up in many oncologic diseases and is especially advantageous for the pediatric population since it avoids redundant examinations and exposure to ionizing radiation in patients who often undergo long-term surveillance. Its clinical application has been studied in many pediatric neoplasms, such as cancer predisposition syndromes, Langerhans cell histiocytosis, lymphoma, sarcomas, and neuroblastoma. The addition of diffusion-weighted sequences allows functional evaluation of neoplastic lesions, which is helpful in the assessment of viable tumor and response to treatment after neoadjuvant or adjuvant therapy. WB-MRI is an excellent alternative to fluorodeoxyglucose-positron emission tomography/computed tomography in oncologic children, with comparable accuracy and the convenience of being radiation-free, fast to perform, and available at a similar cost. The development of new techniques and protocols makes WB-MRI increasingly faster, safer, and more accessible, and it is important for referring physicians and radiologists to recognize the role of this imaging method in pediatric oncology. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 2.

A phase Ib/IIa, open-label, multiple ascending-dose trial of domagrozumab in fukutin-related protein limb-girdle muscular dystrophy.

INTRODUCTION/AIMS: In this study we report the results of a phase Ib/IIa, open-label, multiple ascending-dose trial of domagrozumab, a myostatin inhibitor, in patients with fukutin-related protein (FKRP)-associated limb-girdle muscular dystrophy. METHODS: Nineteen patients were enrolled and assigned to one of three dosing arms (5, 20, or 40 mg/kg every 4 weeks). After 32 weeks of treatment, participants receiving the lowest dose were switched to the highest dose (40 mg/kg) for an additional 32 weeks. An extension study was also conducted. The primary endpoints were safety and tolerability. Secondary endpoints included muscle strength, timed function testing, pulmonary function, lean body mass, pharmacokinetics, and pharmacodynamics. As an exploratory outcome, muscle fat fractions were derived from whole-body magnetic resonance images. RESULTS: Serum concentrations of domagrozumab increased in a dose-dependent manner and modest levels of myostatin inhibition were observed in both serum and muscle tissue. The most frequently occurring adverse events were injuries secondary to falls. There were no significant between-group differences in the strength, functional, or imaging outcomes studied. DISCUSSION: We conclude that, although domagrozumab was safe in patients in limb-girdle muscular dystrophy type 2I/R9, there was no clear evidence supporting its efficacy in improving muscle strength or function.

Determination of skeletal tumor extent: is an isotropic T1-weighted 3D sequence adequate?

OBJECTIVES: To test the hypothesis that an accelerated, T1-weighted 3D CAIPIRINHA SPACE sequence with isotropic voxel size offers a similar performance to conventional T1-weighted 2D TSE (turbo spin echo) for the evaluation of bone tumor extent and characteristics. METHODS: Thirty-four patients who underwent 3-T MRI with 3DT1 (CAIPIRINHA SPACE TSE) and 2DT1 (TSE) were included. Sequence acquisition time was reported. Two radiologists independently evaluated each technique for tumor location, size/length, tumor-to-joint distance, signal intensity, margin/extraosseous extension, and signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. RESULTS: Tumors were located in long (20/36, 55.5%) and pelvic (16/36, 44.4%) bones. 3DT1 sequence required an average acquisition time of 235 s (± 42 s, range 156-372), while two plane 2DT1 sequences combined (coronal and axial) had an average acquisition time of 381 s (± 73 s, range 312-523). There was no difference in the measurements of tumor length and tumor-to-joint distance (p = 0.95) between 3DT1 and 2DT1 images. Tumors were hypointense (17/36, 47.2% vs 17/36, 47.2%), isointense (12/36, 33.3% vs 12/36, 33.3%), or hyperintense (7/36, 19.4% vs 7/36, 19.4%) on 3DT1 vs 2DT1, respectively. Assessment of tumor margins and extraosseous extension was similar, and there was no difference in tumor SNR or CNR (p > 0.05). CONCLUSIONS: An accelerated 3D CAIPIRINHA SPACE T1 sequence provides comparable assessments of intramedullary bone tumor extent and similar tumor characteristics to conventional 2DT1 MRI. For the assessment of bone tumors, the isotropic volume acquisition and multiplanar reformation capability of the 3DT1 datasets can obviate the need for 2DT1 acquisitions in multiple planes. KEY POINTS: • 3DT1 offers an equivalent performance to 2DT1 for the assessment of bone tumor characteristics, with faster and higher resolution capability, obviating the need for acquiring 2DT1 in multiple planes. • There was no difference in the measurements of tumor length and tumor-to-joint distance obtained on 3DT1 and 2DT1 images. • There was no difference in signal-to-noise ratio (SNR) or contrast-to-noise ratio (CNR) measures between 3DT1 and 2DT1.