Faculty Bibliography

Background: Determination of monosodium urate (MSU) deposition in joints by musculoskeletal ultrasound (MSK-US) could have implications for uric acid (UA) management in patients with gout and possibly asymptomatic hyperuricemia (AH). Recently, criteria for sonographic diagnosis of MSU crystal deposition have been developed, but reproducibility of readings using these criteria has not been well established. Methods: We consecutively recruited male patients ages 55-85 during primary care visits to an urban VA hospital. We assessed all patients for gout by ACR criteria, and obtained serum UA levels. Patients were divided into 3 groups: gout, AH (no gout, UA >= 6.9 mg/dL), and controls (no gout, UA <= 6.8 mg/dL). 50 patients (14 with gout, 17 with AH, and 19 controls) returned for subsequent evaluation which included MSK-US of knees and 1st metatarsalphalangeal (MTP) joints to evaluate for the double contour sign (knees) and tophi (MTPs). All images were read blindly by two observers trained in rheumatology and MSK-US. Kappa statistics were used to estimate the amount of agreement between ultrasound measures scored by the two raters. We also calculated the total percent of observations in agreement. Results: Evidence of MSU crystal deposition was found in the same 10 patients by both observers (6 gout, 3 AH, 1 control), and in 3 additional patients by one of the observers (1 gout, 2 AH). These findings were further analyzed by site. MSU crystal deposition was identified in a total of 14 common joints by both observers, and in 4 additional joints by the first observer and 6 additional joints by the second observer. Percentage agreement and kappa statistics for our three primary ultrasound measures were as follows; total joints (n=200, 95% agreement, kappa 0.709), femoral articular cartilage (n=100, 95% agreement, kappa 0.679) and 1st MTPs (n=100, 95% agreement, kappa 0.734). Additional analyses by left and right side are shown in the table below. Ratings on only 10 out of 200 joints were in disagreement. (Table Presented) Conclusions: Both percentage agreement and agreement beyond chance between the raters (as estimated by kappa statistics) were very high for the three ultrasound measures. These findings support the use of MSK-US as a reliable modality for detecting MSU deposition. Since MSU deposition is an indication for urate lowering, this type of imaging could be performed noninvasively at the bedside or in the clinic to help direct therapy in gout patients, with possible implications for treatment in AH patients as well should these findings be reproducible in larger cohorts

OBJECTIVE: The MRI features of the proximal rectus femoris musculotendinous junction have scarcely been described in the literature. The purpose of our study, based on a review of 50 asymptomatic and 20 symptomatic MRI studies, was to define the normal MRI anatomy and MRI features of intrasubstance injury of deep musculotendinous tears of the proximal rectus femoris. CONCLUSION: Axial and coronal MR images are optimal for visualizing the direct and indirect heads, the conjoined tendon, and the deep musculotendinous junction of the proximal rectus femoris. Tears of the deep musculotendinous junction are longitudinal, involving a long segment of the muscle. MRI features include a 'bull's-eye' sign, longitudinal scar, retraction, pseudocyst, and hematoma