SEVERITY OF ARTICULAR-CARTILAGE ABNORMALITY IN PATIENTS WITH OSTEOARTHRITIS - EVALUATION WITH FAST SPIN-ECHO MR VS ARTHROSCOPY

OBJECTIVE. The purpose of this study was to assess the accuracy of fast spinecho MR imaging for depicting the severity of articular cartilage abnormalities in patients with osteoarthritis. SUBJECTS AND METHODS. Twenty-three subjects (10 volunteers less than 35 years old and 13 patients with proved, symptomatic, idiopathic osteoarthritis of the knee of 6 months' to 10 years' clinical duration) underwent fast spin-echo MR imaging of the knee. Two observers graded each articular surface using a five-category scale that took into account abnormalities in the signal intensity of cartilage as well as thickness and contour. The 13 patients also underwent arthroscopic evaluation (as part of a separate protocol) in which cartilage abnormalities were graded by using a similar five-category grading scale, without the graders knowing the results of MR imaging. Articular cartilage was assumed to be normal in the volunteers. RESULTS. One hundred thirty-seven joint surfaces were graded; one surface was obscured by artifact and was excluded. The Spearman rank linear correlation between arthroscopic and MR grading was highly significant (p<.002) for each of the six articular regions evaluated. The MR and arthroscopic grades were the same in 93 (68%) of 137 joint surfaces, they were the same or differed by one grade in 123 surfaces (90%), and they were the same or differed by one or two grades in 129 surfaces (94%). CONCLUSION. Our results suggest that fat-presaturated fast spin-echo MR imaging depicts the severity of articular cartilage abnormalities in osteoarthritis with reasonable accuracy, as compared with arthroscopic evaluation as the standard of reference.