Faculty Bibliography

OBJECTIVE: Sarcoidosis lesions revealed on MRI in the axial skeleton and long bones resemble osseous metastases, which can lead to a potentially significant misdiagnosis. We hypothesized that osseous sarcoidosis lesions could be differentiated from osseous metastases on MRI and sought to propose and evaluate features distinguishing these entities. MATERIALS AND METHODS: MR images obtained at 1.5 T of 34 subjects (22 with osseous metastatic disease, 12 with osseous sarcoidosis) with 79 single or multiple bone lesions (40 metastatic, 39 sarcoidal) were reviewed independently by two blinded, experienced musculoskeletal radiologists. Fluid-sensitive and T1-weighted images were viewed separately. Proposed discriminating features were peri- or intralesional fat, specified border characteristics, and the presence of an extraosseous soft-tissue mass. An additional feature for spinal lesions was posterior element involvement. On the basis of these criteria, the readers provided a binary diagnosis and confidence score. RESULTS: The overall sensitivity for both readers was 46.3% and specificity, 97.4%. T1-weighted images were associated with higher sensitivity than T2-weighted images (59.0% vs 34.1%, respectively; p = 0.025) and with comparable specificity (97.6% vs 97.2%, p = 0.91). Diagnostic accuracy was higher using the discriminators of a mass or posterior element involvement for metastasis (83.3%) than border characteristics (68.0%) or lesion fat (65.0%) for sarcoidosis; the latter two features provided near 100% specificity but poor sensitivity (14.3% and 0%, respectively). Readers reported higher confidence diagnosing osseous sarcoidosis lesions than metastatic lesions, with a trend for higher confidence with T1-weighted images (p = 0.088). CONCLUSION: Osseous sarcoidosis lesions cannot be reliably distinguished from metastatic lesions on routine MRI studies by readers experienced in evaluating these lesions.

OBJECTIVE: The objective of our study was to evaluate the diagnostic utility of conventional radiography for diagnosing bisphosphonate-related atypical subtrochanteric femoral fractures. MATERIALS AND METHODS: Retrospective interpretation of 38 radiographs of complete subtrochanteric and diaphyseal femoral fractures in two patient groups-one group being treated with bisphosphonates (19 fractures in 17 patients) and a second group not being treated with bisphosphonates (19 fractures in 19 patients)-was performed by three radiologists. The readers assessed four imaging criteria: focal lateral cortical thickening, transverse fracture, medial femoral spike, and fracture comminution. The odds ratios and the sensitivity, specificity, and accuracy of each imaging criterion as a predictor of bisphosphonate-related fractures were calculated. Similarly, the interobserver agreement and the sensitivity, specificity, and accuracy of diagnosing bisphosphonate-related fractures (i.e., atypical femoral fractures) were determined for the three readers. RESULTS: Among the candidate predictors of bisphosphonate-related fractures, focal lateral cortical thickening and transverse fracture had the highest odds ratios (76.4 and 10.1, respectively). Medial spike and comminution had odd ratios of 3.8 and 0.63, respectively. Focal lateral cortical thickening and transverse fracture were also the most accurate factors for detecting bisphosphonate-related fractures for all readers. The sensitivity, specificity, and overall accuracy for diagnosing bisphosphonate-related fractures were 94.7%, 100%, and 97.4% for reader 1; 94.7%, 68.4%, and 81.6% for reader 2; and 89.5%, 89.5%, and 89.5% for reader 3, respectively. The interobserver agreement was substantial (kappa > 0.61). CONCLUSION: Radiographs are reliable for distinguishing between complete femoral fractures related to bisphosphonate use and those not related to bisphosphonate use. Focal lateral cortical thickening and transverse fracture are the most dependable signs, showing high odds ratios and the highest accuracy for diagnosing these fractures

MRI has revolutionized the practice of many branches of medicine. However, within the field of Neurology MRI is used almost exclusively to examine the structure of portions of the central nervous system. Despite a limited number of objective tests, MRI remains an underutilized tool in the examination of the peripheral nervous system. This review will briefly discuss the limitations of current testing, and then summarize how the physics of MRI helps predict normal and abnormal findings in disease affecting skeletal muscle. The cardinal radiologic abnormalities affecting muscle (atrophy, hypertrophy, pseudohypertrophy, mass, and altered signal intensity) are reviewed. Special attention is given to how MRI can be utilized during the evaluation of such disorders. Finally, the roles of MRI as a prognostic tool and as a potential endpoint in long-term management of myopathy are evaluated. (c) 2005 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved

OBJECTIVE: Our objective was to determine MRI findings in sarcoidosis patients with musculoskeletal symptoms. CONCLUSION: In sarcoidosis patients with musculoskeletal complaints, MRI reveals marrow and soft-tissue lesions that are occult or underestimated on radiographs. Axial and large-bone lesions may resemble osseous metastases on MRI. Most lesions detected are nonspecific in appearance, except nodular muscle lesions. MRI reveals features suggesting the diagnosis, but with standard protocols, no pathognomonic MRI features were determined

We present a case of primary Nocardia osteomyelitis in the setting of HIV infection. The clinical and radiographic manifestations of musculoskeletal nocardiosis are nonspecific and resemble those of Mycobacterium tuberculosis infection. To our knowledge no other cases of Nocardia osteomyelitis have been reported in the radiology literature

Magnetic resonance (MR) imaging reveals a broad range of musculoskeletal abnormalities in patients with sarcoidosis, including focal and diffuse muscle lesions, soft-tissue masses, joint abnormalities, and marrow infiltration of small and large bones. Long bone and axial skeletal involvement may be occult at conventional radiography but depicted at MR imaging, with an appearance that resembles that of osseous metastases. Sarcoidosis-related findings may be detected at dedicated MR imaging for osteoarticular symptoms in sarcoidosis patients or encountered incidentally at MR imaging performed for other indications. Correlation with clinical and laboratory findings is essential for correct diagnosis because the MR imaging findings are nonspecific in most cases. The radiologist should be aware of potential sarcoidal causes in the differential diagnosis of musculoskeletal lesions in patients with proved or suspected sarcoidosis. Such consideration will have a profound effect on the interpretation of images and on the study of patients with dual diagnoses of sarcoidosis and neoplasm

Many causes of suprascapular nerve entrapment have been described including a small spinoglenoid notch, a tight ligament, boney spurs, and ganglion cysts. In the current patient, suprascapular nerve entrapment was caused by a lipoma in the suprascapular notch. The patient presented with painful shoulder motion that could have been attributed to rotator cuff and acromioclavicular joint disease. However, magnetic resonance imaging and electromyography were consistent with suprascapular nerve entrapment. Treatment of the rotator cuff disease and excision of the lipoma led to resolution of the patient's symptoms. This case is presented as an unusual cause of suprascapular nerve entrapment with a review of its course and anatomy