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 fas t spinecho MR imaging for depicting the severity of articular cartilag e abnormalities in patients with osteoarthritis. SUBJECTS AND METHODS. Twenty-three subjects (10 volunteers less than 35 years old and 13 pa tients 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 u sing a five-category scale that took into account abnormalities in the signal intensity of cartilage as well as thickness and contour. The 1 3 patients also underwent arthroscopic evaluation (as part of a separa te protocol) in which cartilage abnormalities were graded by using a s imilar five-category grading scale, without the graders knowing the re sults of MR imaging. Articular cartilage was assumed to be normal in t he volunteers. RESULTS. One hundred thirty-seven joint surfaces were g raded; one surface was obscured by artifact and was excluded. The Spea rman rank linear correlation between arthroscopic and MR grading was h ighly significant (p<.002) for each of the six articular regions evalu ated. 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 sur faces (90%), and they were the same or differed by one or two grades i n 129 surfaces (94%). CONCLUSION. Our results suggest that fat-presatu rated fast spin-echo MR imaging depicts the severity of articular cart ilage abnormalities in osteoarthritis with reasonable accuracy, as com pared with arthroscopic evaluation as the standard of reference.