Menisci of the knee: radial MR imaging correlated with arthroscopy in 259 patients.

Similar to arthrograms, radial plane magnetic resonance (MR) images of the knee provide cross-sectional images of the menisci that are perpendicular to the long axis of the meniscus. The authors evaluated 259 consecutive patients who underwent MR imaging of the knee and arthroscopy. Radial multiplanar gradient-recalled-echo imaging was performed--with repetition time of 700 msec, echo times of 12 and 31 msec (700/12, 31), and a flip angle of 20 degrees--as well as sagittal spin-echo imaging (2,500/20, 80). The radial and sagittal images were interpreted separately and then in combination, and findings were compared with arthroscopic reports. There was no statistical difference between the interpretations of the radial and sagittal images in the evaluation of the menisci. When the interpretations of the radial and sagittal images were combined, the sensitivity and specificity improved slightly. The radial images increased the conspicuity of meniscal tears but at the expense of anatomic detail. The sagittal images enabled better evaluation of the meniscocapsular attachment region and some flap tears of the meniscal free edge. The interpretive accuracies of the combination of sagittal and radial images were 92% and 93% for the medial and lateral menisci, respectively.