Fast spin-echo MR of the articular cartilage in the osteoarthrotic knee. Correlation of MR and arthroscopic findings.

Abstract

The objective was to assess the efficacy of fast spin-echo (FSE) imaging in the detection of articular cartilage abnormality in osteoarthrosis of the knee. We studied 356 articular surfaces in 73 knees that had been examined by both MR imaging and arthroscopy. The MR images were obtained with FSE imaging (TR/TE 4200/100) on a 0.5 T unit. The surface abnormalities of the articular cartilage that were detected by MR imaging were compared with the arthroscopic findings. The overall sensitivity and specificity of MR in detecting chondral abnormalities were 60.5% (158/261) and 93.7% (89/95) respectively. MR imaging was more sensitive to the higher grade lesions: 31.8% (34/107) in grade 1; 72.4% (71/98) in grade 2; 93.5% (43/46) in grade 3; and 100% (10/10) in grade 4. The MR and arthroscopic grades were the same in 46.9% (167/356), and differed by no more than 1 grade in 90.2% (321/356) and 2 grades in 99.2% (353/356). The correlation between arthroscopic and MR grading scores was highly significant with a correlation coefficient of 0.705 (p < 0.0001). FSE sequence was less sensitive to mild cartilage abnormality but useful in detecting moderate to severe abnormality and in evaluating the degree of articular cartilage abnormality.