High resolution computed tomography of knee menisci.

Sixty four menisci in 22 patients were examined by non-contrast high resolution computed tomography (CT). Fifty four menisci were imaged on a GE 8800 CT scanner. The other 10 were imaged on a GE 9800 CT scanner. Nineteen menisci were shown to be torn on arthrography and/or arthroscopy--12 medially and 7 laterally. The remaining menisci were normal. When the meniscal CTs were reviewed collectively by three observers without knowledge of arthrographic or arthroscopic results, sensitivity was 63%, specificity was 93%, and accuracy was 84%. Although only 10 menisci were imaged on the GE 9800 scanner, the sensitivity in this subset of scans was 83%, the specificity 100%, and the accuracy was 90%. These results suggest that noncontrast CT cannot replace arthrography or arthroscopy, but it is possible that images obtained on the GE 9800 or comparable CT scanner may be accurate enough to be used for screening of meniscal tears in selected patients.