OBJECTIVE: Adhesive capsulitis is a clinical syndrome of pain and severely 
decreased joint motion ("frozen shoulder") caused by thickening and contraction 
of the joint capsule and synovium. Although arthrographic criteria for the 
diagnosis have been described, to our knowledge, the MR characteristics have not 
been reported. Accordingly, we studied the MR findings in 10 patients with this 
syndrome.
MATERIALS AND METHODS: MR images of 25 subjects were included in the study. Nine 
had adhesive capsulitis documented by arthrography, and one had adhesive 
capsulitis proved at surgery. The MR findings in these patients were compared 
with those of 15 asymptomatic volunteers. Images were assessed for thickness of 
the joint capsule and synovium, for thickness of the coracohumeral ligament, and 
for volume of articular fluid. Capsule and synovium thickness was measured 
adjacent to the axillary recess. The volume of intraarticular fluid was 
calculated from direct measurements of the axillary recess and biceps tendon 
sheath. The rotator cuff interval was qualitatively evaluated for the presence 
of abnormal tissue.
RESULTS: Thickening of capsule and synovium on MR images was characteristic of 
adhesive capsulitis, with a significant difference between mean thickness in 
patients with adhesive capsulitis (5.2 mm) and in asymptomatic volunteers (2.9 
mm) (p < .01). Capsule and synovium thickness greater than 4 mm was a specific 
(95%) and sensitive (70%) criterion for the diagnosis of adhesive capsulitis. 
There was no significant difference in volume of articular fluid or thickness of 
the coracohumeral ligament between patients with adhesive capsulitis and 
asymptomatic volunteers (p > .5). The rotator cuff interval was not useful for 
assessing changes of adhesive capsulitis.
CONCLUSION: Joint capsule and synovium thickness greater than 4 mm is a useful 
MR criterion for the diagnosis of adhesive capsulitis. The volume of articular 
fluid seen on MR images is not significantly diminished in patients with 
adhesive capsulitis.