CT-guided percutaneous biopsy of sclerotic bone lesions: diagnostic outcomes.

OBJECTIVE: To determine the diagnostic yield of CT-guided percutaneous biopsy of densely sclerotic bone lesions. MATERIALS AND METHODS: We retrospectively analyzed CT-guided percutaneous bone biopsies performed at our institution from September 2008 through August 2011 (329 cases) and from September 2012 through August 2015 (324 cases) after adoption of a battery-powered drill system (OnControl). Bone lesions were included in the analysis if they were >70% sclerotic by visual inspection, had a density > 2 times that of adjacent trabecular bone, and had an attenuation of ≥250 HU. Pathological fractures, diskitis-osteomyelitis, and osteoid osteomas were excluded. Eligible cases were characterized by lesion location, maximum lesion diameter, mean density, biopsy needle type and gauge, reported complications, and histological diagnosis. Clinical and imaging follow-up was used to confirm histological diagnosis. Cases in which a benign histological diagnosis could not be confirmed by imaging over a minimum period of 1 year were excluded. RESULTS: A total of 37 biopsies of sclerotic bone lesions met the inclusion criteria, 17 of which were performed with a power drill needle and 20 of which were performed with a manually driven needle. The mean lesion density was 604.1 HU. The overall diagnostic yield was 78.4%; overall diagnostic accuracy was 94.6%, and the false-negative rate was 5.4%. Diagnostic yield and accuracy were 82.4% and 100% respectively, with a power drill and 75% and 90% respectively, with a manual device. Diagnostic yield for lesions ≥700 HU was 90% (9 out of 10). CONCLUSION: Densely sclerotic bone lesions are amenable to percutaneous needle biopsy.

Comparison of a fast 5-min knee MRI protocol with a standard knee MRI protocol: a multi-institutional multi-reader study.

PURPOSE: To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. MATERIALS AND METHODS: One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015-1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. RESULTS: Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0-99.5%), with no excess disagreement (≤ 1.2; 95% CI, -4.2 to 3.8%), across all structures. Frequency of major findings (1.1-22.4% across structures) on fast and standard MRI was not significantly different (p ≥ 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p < 0.001). Sensitivities (59-100%) and specificities (73-99%) of fast and standard MRI were not significantly different for meniscal and ligament tears (95% CI for difference, -0.08-0.08). For cartilage defects, fast MRI was slightly less sensitive (95% CI for difference, -0.125 to -0.01) but slightly more specific (95% CI for difference, 0.01-0.5) than standard MRI. CONCLUSION: A fast 5-min MRI protocol is interchangeable with and has similar accuracy to a standard knee MRI for evaluating internal derangement of the knee.

Pathomechanics and Magnetic Resonance Imaging of the Thrower's Shoulder.

Repetitive, high-velocity overhead throwing can lead to several adaptive changes in the throwing shoulder, which over time lead to structural microtrauma and eventually overt injury. MR imaging is a useful imaging modality to evaluate these changes and to characterize their acuity and severity. Understanding the throwing motion and the effects of this motion on the structures of the shoulder can help radiologists to recognize these findings and provide useful information to referring physicians, which may affect the treatment of these athletes. This article reviews shoulder pathomechanics and MR imaging findings in overhead throwing athletes.

Hybrid convolution kernel: optimized CT of the head, neck, and spine.

OBJECTIVE: Conventional CT requires generation of separate images utilizing different convolution kernels to optimize lesion detection. Our goal was to develop and test a hybrid CT algorithm to simultaneously optimize bone and soft-tissue characterization, potentially halving the number of images that need to be stored, transmitted, and reviewed. MATERIALS AND METHODS: CT images generated with separate high-pass (bone) and low-pass (soft tissue) kernels were retrospectively combined so that low-pass algorithm pixels less than -150 HU or greater than 150 HU are substituted with corresponding high-pass kernel reconstructed pixels. A total of 38 CT examinations were reviewed using the hybrid technique, including 20 head, eight spine, and 10 head and neck scans. Three neuroradiologists independently reviewed all 38 hybrid cases, comparing them to both standard low-pass and high-pass kernel convolved images for characterization of anatomy and pathologic abnormalities. The conspicuity of bone, soft tissue, and related anatomy were compared for each CT reconstruction technique. RESULTS: For the depiction of bone, in all 38 cases, the three neuroradiologists scored the hybrid images as being equivalent to high-pass kernel reconstructions but superior to the low-pass kernel. For depiction of extracranial soft tissues and brain, the hybrid kernel was rated equivalent to the low-pass kernel but superior to that of the high-pass kernel. CONCLUSION: The hybrid convolution kernel is a promising technique affording optimized bone and soft tissue evaluation while potentially halving the number of images needed to be transmitted, stored, and reviewed.