Neurogenic heterotopic ossification of the hip: Magnetic resonance imaging versus computed tomography for pre-surgical assessment.

PURPOSE: Neurogenic heterotopic ossification (NHO) of the hip is a frequent complication of spinal cord injuries, often requiring surgical management. Pre-surgical imaging assessment is essential, usually with computed tomography (CT)-scan. We aimed to compare magnetic resonance imaging (MRI) and CT for pre-surgical imaging assessment of the NHO, particularly for their relationships with vessels and nerves. METHOD: This prospective study included consecutive patients who underwent surgery for NHO from July 2019 to April 2022. All patients had CT angiography and MRI including Zero Echo Time and TRICKS sequences. Radiologists used standardized reports for CT and MRI to evaluate NHO and their features, bone mineralization, and relation to the arteries, veins and nerves. Agreement between pre-surgical CT and MRI was evaluated. RESULTS: Twenty-four patients (mean age: 53.5 ± 12.2 years) were included, among which 7 had bilateral NHO (31 hips). NHO were anterior in 15/31 hips (48 %), multifragmented in 25/31 hips (81 %). Mild and significant demineralization was most frequent. Gutter and tunnel were reported in 11.1 % of the arteries. Nerves were more often identified in MRI than in CT-scan. Agreement coefficients between CT and MRI were excellent for NHO location (0.95) and implantation (0.92), good for fragmentation (0.70), contact with joint capsule (0.66), bone mineralization (0.74), and relation to arteries (0.85), veins (0.76), sciatic nerve (0.7) and moderate for femoral nerve (0.47). CONCLUSION: MRI exhibited a good agreement with CT for pre-surgical assessment of NHO of the hip, especially to evaluate their relationships with the arteries, veins and sciatic nerve. Femoral nerves were more often identified in MRI than in CT-scan.

The multifaceted musculoskeletal hydatid disease.

Musculoskeletal hydatid disease is rare and can be located anywhere but most commonly the bone and muscles of the spine, pelvis, then the lower limbs. Imaging is essential for its diagnosis, performing the pre-therapeutic assessment, guiding possible percutaneous treatments, and providing post-therapeutic follow-up. Musculoskeletal hydatidosis can take several forms that may suggest other infections and tumors or pseudotumors. MRI and CT are superior for its diagnosis but ultrasound and radiography remain the most accessible examinations in developing countries where this parasitosis is endemic. In this review, we provide an overview of this disease and describe its different imaging patterns in soft tissue and bone involvement that should be sought to support the diagnosis.

Analysis of muscle magnetic resonance imaging of a large cohort of patient with VCP-mediated disease reveals characteristic features useful for diagnosis.

BACKGROUND: The diagnosis of patients with mutations in the VCP gene can be complicated due to their broad phenotypic spectrum including myopathy, motor neuron disease and peripheral neuropathy. Muscle MRI guides the diagnosis in neuromuscular diseases (NMDs); however, comprehensive muscle MRI features for VCP patients have not been reported so far. METHODS: We collected muscle MRIs of 80 of the 255 patients who participated in the "VCP International Study" and reviewed the T1-weighted (T1w) and short tau inversion recovery (STIR) sequences. We identified a series of potential diagnostic MRI based characteristics useful for the diagnosis of VCP disease and validated them in 1089 MRIs from patients with other genetically confirmed NMDs. RESULTS: Fat replacement of at least one muscle was identified in all symptomatic patients. The most common finding was the existence of patchy areas of fat replacement. Although there was a wide variability of muscles affected, we observed a common pattern characterized by the involvement of periscapular, paraspinal, gluteal and quadriceps muscles. STIR signal was enhanced in 67% of the patients, either in the muscle itself or in the surrounding fascia. We identified 10 diagnostic characteristics based on the pattern identified that allowed us to distinguish VCP disease from other neuromuscular diseases with high accuracy. CONCLUSIONS: Patients with mutations in the VCP gene had common features on muscle MRI that are helpful for diagnosis purposes, including the presence of patchy fat replacement and a prominent involvement of the periscapular, paraspinal, abdominal and thigh muscles.

Caveolinopathy: Clinical, histological, and muscle imaging features and follow-up in a multicenter retrospective cohort.

BACKGROUND AND PURPOSE: CAV3 gene mutations, mostly inherited as an autosomal dominant trait, cause various skeletal muscle diseases. Clinical presentations encompass proximal myopathy, distal myopathy, or isolated persistent high creatine kinase (CK) with a major overlapping phenotype. METHODS: Twenty-three patients with CAV3 symptomatic mutations, from 16 different families, were included in a retrospective cohort. Mean follow-up duration was 24.2 ± 15.0 years. Clinical and functional data were collected during the follow-up. The results of muscle imaging, electroneuromyography, muscle histopathology, immunohistochemistry, and caveolin-3 Western blot analysis were also compiled. RESULTS: Exercise intolerance was the most common phenotype (52%). Eighty percent of patients had calf hypertrophy, and only 65% of patients presented rippling. One patient presented initially with camptocormia. A walking aid was required in only two patients. Electroneuromyography was mostly normal. CK level was elevated in all patients. No patient had cardiac or respiratory impairment. Muscle imaging showed fatty involvement of semimembranosus, semitendinosus, rectus femoris, biceps brachialis, and spinal muscles. Almost all (87%) of the biopsies were abnormal but without any specific pattern. Whereas a quarter of patients had normal caveolin-3 immunohistochemistry results, Western blots disclosed a reduced amount of the protein. We report nine mutations, including four not previously described. No phenotype-genotype correlation was evidenced. CONCLUSIONS: Caveolinopathy has diverse clinical, muscle imaging, and histological presentations but often has limited functional impact. Mild forms of the disease, an atypical phenotype, and normal caveolin-3 immunostaining are pitfalls leading to misdiagnosis.

Systemic light chain amyloidosis myopathy responsive to daratumumab monotherapy.

BACKGROUND AND PURPOSE: Amyloid myopathy is a rare and severe manifestation of systemic light chain (AL) amyloidosis. Early diagnosis and staging are mandatory for optimal therapy, given the rapid progression of muscle weakness. Despite the efficacy of bortezomib-based treatment regimens, there is a lack of therapeutic alternatives in non-responsive patients. METHOD: The case report of a patient with systemic AL amyloidosis myopathy treated with daratumumab is presented. RESULTS: A 70-year-old man displayed severe proximal muscle weakness which had developed over a 10-month period. Blood tests revealed an immunoglobulin A lambda monoclonal gammopathy, whilst muscle biopsy showed amyloid deposits within the arteriolar walls, confirming the diagnosis of amyloid myopathy associated with AL amyloidosis. Initial treatment with a bortezomib-based regimen showed no clinical or hematological improvement. After switching to daratumumab monotherapy, our patient achieved a favorable evolution with respect to functional muscle scoring and a complete hematological response. CONCLUSION: To our knowledge, this is the first case report of an amyloid myopathy showing a remarkable clinical improvement in response to daratumumab monotherapy. It thereby highlights the potential of daratumumab as a monotherapeutical approach to the treatment of amyloid myopathy complicating AL amyloidosis.