A positioning device to allow rotation for cine-MRI of the distal radioulnar joint

'Cine-mode' magnetic resonance imaging (MRI) is useful in the diagnosis and treatment of patients with disorders of joint motion. We have designed a d evice for imaging of the distal radioulnar joint by cine-MRI. Five normal w rists and eight patients with rheumatoid arthritis were investigated prior to surgery for subluxation of the distal radioulnar joint. Normally, the ra dius moves in a constant are around the ulna, whereas in rheumatoid wrists the centre of rotation varies continuously with increase in rotation. The d evice should prove helpful in imaging disorders of the distal radioulnar jo int.