Cartilage thickness in cadaveric ankles: measurement with double-contrast multi-detector row CT arthrography versus MR imaging.

PURPOSE To test the accuracy of double-contrast multi-detector row computed tomographic (CT) arthrography for measurement of cartilage thickness in cadaveric ankles and to compare this technique with three-dimensional (3D) fat-suppressed spoiled gradient-echo in the steady state (FS-SPGR) magnetic resonance (MR) imaging. MATERIALS AND METHODS Five cadaveric ankles were used. In the ankle specimens, five to nine 1.5-mm-diameter holes were drilled across the joint traversing the tibial subchondral bone, tibial articular cartilage, talar dome cartilage, and talar subchondral bone. The ankle specimens were obtained and used according to institutional policies. Each ankle specimen was imaged first by using 3D FS-SPGR MR imaging with a 1.5-T magnet and then by using double-contrast arthrography followed by CT with a four-detector row scanner (ie, double-contrast multi-detector row CT arthrography). The section thickness used for CT scanning was 1.0 mm reconstructed in 0.5-mm intervals. The MR and CT images obtained in the five specimens were then downloaded to a workstation, where a measurement tool was used to measure the cartilage thickness at each hole. The physical measurement of cartilage thickness at each hole was used as the reference standard with which the MR imaging and CT measurements were compared. Linear regression and correlation analyses were performed by using a statistical computer program. RESULTS Double-contrast arthrography followed by multi-detector row CT, as compared with 3D FS-SPGR MR imaging, enabled more accurate measurement of the physical cartilage thickness in the ankle (P < .001). CONCLUSION In this study of five cadaveric ankles, multi-detector row CT arthrography was more accurate than 3D FS-SPGR MR imaging for measurement of articular cartilage thickness in the ankle.