IMAGING OF OSSEOUS AND CARTILAGINOUS INTRAARTICULAR BODIES IN THE KNEE - COMPARISON OF MR-IMAGING AND MR ARTHROGRAPHY WITH CT AND CT ARTHROGRAPHY IN CADAVERS

PURPOSE: To compare magnetic resonance (MR) imaging and MR arthrograph y with computed tomography (CT) and CT arthrography in the detection o f intraarticular bodies in the knee. MATERIALS AND METHODS: Cuboid (3- or 6-mm-long sides) osseous and cartilaginous bodies were implanted i n 16 cadaveric knee specimens. MR imaging was performed with T1-weight ed spin-echo (SE), T2-weighted SE, proton-density-weighted SE, gradien t recalled acquisition in the steady state (GRASS), and spoiled GRASS sequences. MR arthrography was performed in two phases with saline and 2 mmol/L gadopentetate dimeglumine. CT and CT arthrography were perfo rmed in the transaxial plane. RESULTS: MR arthrography yielded the hig hest accuracy for the detection of osseous and cartilaginous bodies co mbined (92%) and was significantly (P < .01) better than MR imaging (5 7%-70%), CT arthrography (80%), and CT (74%). Accuracy of CT arthrogra phy was significantly better than that of MR imaging and that of CT. A ccuracy of saline-enhanced MR arthrography was significantly inferior (P < .001) to that of gadolinium-enhanced MR arthrography. CONCLUSION: MR arthrography is the best imaging technique for detection of indivi dual intraarticular bodies. CT arthrography is the second most accurat e method. Spoiled GRASS and T2-weighted SE sequences are the most accu rate at MR imaging. The presence of intraarticular fluid and performan ce of saline-enhanced MR arthrography improve detectability of intraar ticular bodies.