Effect of chondrocalcinosis on the MR imaging of knee menisci

OBJECTIVE. Our goal was to determine the influence of chondrocalcinosis on MR imaging in the detection of meniscal tears. MATERIALS AND METHODS. A retrospective review was performed of knee MR imag ing and arthroscopy records from two university hospitals between 1996 and 1998. Seventy individuals had radiographic evidence of chondrocalcinosis an d underwent knee MR imaging. Thirty-seven of these individuals had undergon e arthroscopy for further evaluation of their symptoms. MR imaging sensitiv ity and specificity in the detection of medial and lateral meniscal tears w ere calculated in these 37 patients who had radiographic evidence of chondr ocalcinosis and in a control group of 34 patients who underwent MR imaging and arthroscopy but did not have knee chondrocalcinosis. RESULTS. In the chondrocalcinosis group, MR imaging sensitivity, specificit y, and accuracy for meniscal tear were 78%, 71%, and 78%, respectively, for the lateral meniscus, and 89%,72%, and 81% for the medial meniscus. The co ntrol group showed sensitivity, specificity, and accuracy of 93%, 100%, and 97%, respectively, for the lateral meniscus and 100% in all cases for the medial meniscus. The MR imaging detection of meniscal tears in both the lat eral and medial compartments combined is significantly poorer in the presen ce of chondrocalcinosis (p < 0.005). CONCLUSION. MR imaging sensitivity and specificity for detection of menisca l tear is decreased in the presence of meniscal chondrocalcinosis. Chondroc alcinosis appeared as a high-signal-intensity region on Tl-weighted, interm ediate-weighted, and inversion recovery sequences. The high signal of chond rocalcinosis on inversion recovery sequence is an interesting observation t hat to our knowledge has not been previously reported. Radiographic correla tion with the MR imaging examination can help prevent overdiagnosing menisc al tears.