Carpal tunnel syndrome caused by tophaceous gout: CT and MR imaging features in 20 patients

OBJECTIVE. The objective of this study is to describe the CT and MR imaging findings of gouty tophi in the wrist and present this entity as a cause of carpal tunnel syndrome. MATERIALS AND METHODS. Retrospective review of the CT (n = 18) and MR imagi ng (n = 20) studies of the wrist in patients with a documented diagnosis of gout who presented with gout-related carpal tunnel syndrome was performed; images of 24 wrists were collected over a 5-year period. Patient populatio n included 20 men, who ranged in age from 35 to 76 years. All images were r eviewed by two musculoskeletal radiologists who reached a consensus opinion . Surgical correlation was available in 12 patients. RESULTS. Tophi were found in the floor of the carpal tunnel (n = 18), carpa l bones (n = 17), radiocarpal joint (n = 17), and extensor tendons or tendo n sheaths (n = 16) of the wrist. All tophi showed similar signal characteri stics (from low to intermediate signal intensity on T1-weighted images with heterogeneous signal intensity on T2-weighted images) with the exception o f tophi in the floor of the carpal tunnel (low signal intensity on T2-weigh ted images). Varying degrees of calcification were noted on CT and MR imagi ng studies. Gadolinium-enhanced MR studies showed heterogeneous enhancement . CONCLUSION. Gouty tophi should be entertained as a cause of carpal tunnel s yndrome in the appropriate patient population. Familiarity with this entity and its imaging characteristics may prove helpful in diagnosis and preoper ative planning.