Popliteal Artery-Related Pathologies in Athletes-A Primer for Musculoskeletal Radiologists.

Vascular complications in athletes are common and mimic musculoskeletal injuries such as muscle sprains, fractures, and cartilage abnormalities. They include traumatic vascular injuries and more subtle pathologies like entrapment syndromes, pseudoaneurysms, arterial occlusions, and venous thrombosis. Such vascular complications may be occult on imaging and can be difficult for a musculoskeletal radiologist to diagnose, resulting in a lack of timely diagnosis and potentially limb-threatening consequences. Although the final diagnosis may require multidisciplinary input from orthopaedic, sports and exercise medicine, and vascular and interventional radiology inputs, a musculoskeletal radiologist with prior knowledge of such conditions can be the first to diagnose such conditions aiding the athlete's performance. A musculoskeletal radiologist should pay due attention to anatomical courses of vascular channels and look for potential causes of vascular compression, aberrant myotendinous bands, accessory muscles, etc., before concluding a computed tomography (CT) or magnetic resonance imaging (MRI) as normal. Doppler ultrasound, CT, or MR angiography are commonly employed techniques for primary evaluation, whereas digital subtraction angiography is generally reserved for troubleshooting as advanced dynamic imaging.

Imaging of Chronic Kidney Disease-Mineral and Bone Disorder.

The characteristic radiological appearances of metabolic bone and soft tissue diseases in chronic renal failure are described and illustrated in the context of advancing understanding of the complex metabolic changes that occur in chronic kidney disease and its management.

Imaging calcinosis in patients with systemic sclerosis by radiography, computerised tomography and magnetic resonance imaging.

INTRODUCTION: Objective outcome measures are needed to facilitate clinical trials of much needed treatments for calcinosis in systemic sclerosis (SSc). Our primary aim was to compare radiography, computed tomography (CT) and magnetic resonance imaging (MRI) to measure calcinotic lesions. Secondary objectives included to examine reproducibility of radiography and MRI, and inter-rater reliability of MRI. MATERIALS AND METHODS: 15 patients with SSc and clinically apparent calcinosis were studied. On one hand, radiography, CT and MRI were performed. The number (all techniques), area (radiography) and volume (CT and MRI) of calcinotic areas were extracted by 'blinded' musculoskeletal radiologists. RESULTS: No significant difference (P = 0.289) in the mean (SD) number of lesions (per hand) was seen between radiography: 5.4 (4.6), CT: 6.3 (6.5) and MRI: 5.2 (3.9). Mean (SD) lesion volumes were systematically higher as measured by CT: 656.7 (1939.9) mm3 compared to MRI: 442 (1083.2) mm3. Radiographic area was highly correlated (P = <0.0001) with volume for both CT and MRI (rho=0.91 and 0.87, respectively). DISCUSSION: It was possible to measure calcinotic lesions by radiography, CT and MRI, with CT volume being higher than MRI volume. Radiographic area was highly correlated with CT and MRI volume, suggesting that low cost radiographs may give comparable information to 3-dimensional imaging. Our findings provide further insight into the development of objective outcome measures to facilitate future calcinosis clinical trials.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping of talar osteochondral lesions: Indicators of clinical outcomes.

PURPOSE: To evaluate the utility of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T2 mapping in evaluation of type II osteochondral lesions (OCLs) of the talus and define cutoff values for identifying patients with good/poor clinical outcomes. MATERIALS AND METHODS: 28 patients (mean age, 42.3 years) underwent T2 mapping and dGEMRIC at least 1.5 years (mean duration, 3.5 years) after microfracture (n = 12) or conservative (n = 16) treatment for type II OCL. Clinical outcomes were considered good with an American Orthopedic Foot and Ankle Society score ≥80. The T1 /T2 -values and indices of repair tissue (RT; cartilage above the OCL) were compared to those of the adjacent normal cartilage (NC) by region-of-interest analysis. The ability of the two methods to discriminate RT from NC was determined by area under the receiver operating characteristics curve (AUC) analysis. The Youden index was maximized for T1 /T2 measures for identifying cutoff values indicative of good/poor clinical outcomes. RESULTS: Repair tissue exhibited lower dGEMRIC values (629.83 vs. 738.51 msec) and higher T2 values (62.07 vs. 40.69 msec) than NC (P < 0.001). T2 mapping exhibited greater AUC than dGEMRIC (0.88 vs. 0.69; P = 0.0398). All T1 measures exhibited higher maximized Youden indices than the corresponding T2 measures. The highest maximized Youden index for T1difference was observed at a cutoff value of 84 msec (sensitivity, 78%; specificity, 83%). CONCLUSION: While T2 mapping is superior to dGEMRIC in discriminating RT, the latter better identifies good/poor clinical outcomes in patients with type II talar OCL. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1601-1610.

MR imaging features of spindle cell lipoma.

OBJECTIVE: To assess the MR imaging features of spindle cell lipomas (SCL) and to compare these appearances directly with the histopathological findings. MATERIALS AND METHODS: A retrospective review of our soft tissue tumor database was performed. This yielded 1,327 histologically proven lipomas, of which 25 were confirmed as being SCLs. Fourteen of the 25 patients had MR examinations available for review and only these patients were included in our study. Lesions were assessed at MR examination for the degree of internal fat signal content with grade 0 representing 0 % fat signal and grade 4 100 % fat signal. The degree of fat suppression and contrast-enhancement pattern were also recorded. The excision specimens were independently reviewed by a consultant histopathologist. The histology specimens were assessed for the amount of internal fat and non-adipose tissue and graded using the same scale applied for the imaging. Where core needle biopsy (CNB) was performed, the CNB specimens were also examined for positive features of SCL. RESULTS: In our study, 93 % (13/14) of our patients were male and the average age was 58 years. 65 % (9/14) of the lesions presented in the upper back, shoulder, or neck. All lesions were subcutaneous. 35 % (5/14) of the SCLs demonstrated grade 3 (>75 %) or grade 4 (100 %) fat signal on MR examination. 35 % (5/14) of the lesions had grade 2 (25-75 %) fat signal and 29 % (4/14) of the lesions demonstrated grade 0 (0 %) or grade 1 (<25 %) fat signal. 43 % (6/14) of lesions demonstrated homogenous fat suppression, 28 % (4/14) showed focal areas of high internal signal, and 28 % (4/14) had diffuse internal high signal on fluid-sensitive fat-saturated sequences. 86 % (6/7) of the cases demonstrated septal/nodular enhancement. The diagnosis was evident on the CNB specimen in 100 % (9/9) cases. The histopathology fat content grade was in agreement with the imaging grade in 86 % (12/14) cases. CONCLUSIONS: The internal signal pattern of SCL can range broadly, with low fat content lesions seen almost as commonly as intermediate and high fat content lesions. We also found that the fat:non-fat internal MR signal pattern of these lesions is accurately reflected in their composition at histology.