The Radiohumeral Synovial Fold: Analysis with 3D Isotropic MR Imaging in 80 Asymptomatic Subjects

Abstract

Purpose: To evaluate prospectively the size of the synovial fold protruding into the radiohumeral joint using 3D isovoxel MR imaging in asymptomatic volunteers, and to find a new reference value of the synovial fold on MR imaging. Materials and methods: Eighty asymptomatic volunteers (36 women, 44 men; age range, 23-56 years; median age, 39; 20 patients in each decade from 20s to the 50s) were examined in this study. MR imaging of both sides of the elbow was performed using 3D isovoxel fast field-echo sequence with selective water excitation. The width of the synovial fold, which is defined as the distance between the tip of the synovial fold and the outer edge of the radial head, was measured at eight locations on the radiohumeral joint. We analyzed the relationship between the results and age, sex, and handedness. Results: The posterior synovial fold was largest (range, 0.2-11.6 mm; median, 6.9 mm; 95th percentile, 10.0 mm). The width of the lateral synovial fold and posterolateral synovial fold was larger in patients in their 50s than in their 20s (p < 0.05 and p < 0.01, respectively). Conclusion: Most normal synovial folds are smaller than 10.0 mm in width. Aging is a factor which influences the width of lateral to posterolateral synovial folds.