Prevalence of avascular necrosis in idiopathic inflammatory myositis: a single center 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 2003-2017 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: 1680 patients were diagnosed with IIM. Fifty-one patients developed AVN, with an overall prevalence of 3%. Musculoskeletal magnetic resonance imaging (MSK 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 age at diagnosis of 44.5 ± 12.4 years. 61% had dermatomyositis (DM) and 29% had polymyositis (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%. 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 were found to be associated with AVN development

Grade 1 and 2 Chondrosarcomas of the Chest Wall: CT Imaging Features and Review of the Literature

The purpose of our retrospective article is to review the CT imaging features of chondrosarcomas of the chest wall with pathologic correlation. For 26 subjects with biopsy-proven chondrosarcomas of the chest wall, two musculoskeletal radiologists retrospectively reviewed 26 CT scans in consensus. Descriptive statistics were performed. The mean tumor size was 57 mm. Twenty (20/26, 77%) chondrosarcomas were located in the ribs and six (6/26, 23%) in the sternum. The majority were lytic (19/26, 73%) with <25% calcification (15/26, 58%), and with a soft tissue mass (22/27, 85%). In this study CT features of grade 1 chondrosarcoma overlapped with those of grade 2 tumors. In conclusion, chondrosarcomas of the chest wall are generally lytic with an associated soft tissue mass, showing little calcified matrix and low-to-intermediate grade

MRI features of peripheral traumatic neuromas

To describe the MRI appearance of traumatic neuromas on non-contrast and contrast-enhanced MRI sequences. This IRB-approved, HIPAA-compliant study retrospectively reviewed 13 subjects with 20 neuromas. Two observers reviewed pre-operative MRIs for imaging features of neuroma (size, margin, capsule, signal intensity, heterogeneity, enhancement, neurogenic features and denervation) and the nerve segment distal to the traumatic neuroma. Descriptive statistics were reported. Pearson's correlation was used to examine the relationship between size of neuroma and parent nerve. Of 20 neuromas, 13 were neuromas-in-continuity and seven were end-bulb neuromas. Neuromas had a mean size of 1.5 cm (range 0.6-4.8 cm), 100 % (20/20) had indistinct margins and 0 % (0/20) had a capsule. Eighty-eight percent (7/8) showed enhancement. All 100 % (20/20) had tail sign; 35 % (7/20) demonstrated discontinuity from the parent nerve. None showed a target sign. There was moderate positive correlation (r = 0.68, p = 0.001) with larger neuromas arising from larger parent nerves. MRI evaluation of the nerve segment distal to the neuroma showed increased size (mean size 0.5 cm ± 0.4 cm) compared to the parent nerve (mean size 0.3 cm ± 0.2 cm). Since MRI features of neuromas include enhancement, intravenous contrast medium cannot be used to distinguish neuromas from peripheral nerve sheath tumours. The clinical history of trauma with the lack of a target sign are likely the most useful clues. • MRI features of neuromas include enhancement and lack of a target sign. • Contrast material cannot be used to distinguish traumatic neuromas from PNSTs. • Traumatic neuromas can simulate peripheral nerve neoplasms on imaging

Characterization of indeterminate soft tissue masses referred for biopsy: What is the added value of contrast imaging at 3.0 tesla?

To assess the added value of contrast-enhanced (CE) MR sequences (static CE-MR sequences, dynamic CE-MR sequences) to noncontrast enhanced MR sequences (non-CE-MR sequences) including T1, fluid-sensitive, and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping for characterizing "indeterminate" soft tissue masses (STMs) as benign or malignant. Thirty-nine patients with indeterminate STMs (27 benign, 12 malignant) underwent 3 Tesla MRI with conventional non-CE-MR sequences (T1-weighted, fluid-sensitive), DWI (b-values 50, 400, 800, ADC mapping), dynamic CE-MR sequences (7-s time resolution), and static CE-MR sequences. Two readers independently reviewed imaging in four sessions (conventional non-CE-MR sequences alone, conventional+DWI/ADC, conventional+DWI/ADC+static CE-MR sequences, conventional+DWI/ADC+static CE-MR sequences dynamic CE-MR sequences). Readers recorded the potential of malignancy at each session; reader diagnostic performance (receiver operating characteristics analysis) and inter-observer variability (weighted kappa [k]) were determined. Diagnostic performance for distinguishing benign and malignant STMs was highest with the addition of dynamic CE-MR sequences (reader 1, area under the curve [AUC] 0.91; reader 2, AUC 0.88). The diagnostic performance of static CE-MR sequences (reader 1, AUC 0.86; reader 2, AUC 0.84) was not superior to non-CE-MR sequences with DWI (reader 1, AUC 0.88; reader 2, AUC 0.8). Interobserver agreement was: k = 0.82 (static CE-MRI), k = 0.79 (dynamic CE-MRI), k = 0.53 (non-CE-MR sequences without DWI), and k = 0.63 (with DWI). Non-CE-MR sequences offer similar diagnostic performance to imaging with the addition of static CE-MR sequences, but their interobserver reliability is lower. The addition of dynamic CE-MR sequences offers the higher diagnostic performance for distinguishing benign and malignant indeterminate STMs. 3 J. Magn. Reson. Imaging 2017;45:390-400