A Study on MR images of the Articular Cartilage in Medial-Type Osteoarthritis of the Knee

抄録

Changes in the articular cartilage of 88 knees of 73 cases (age range 40〜78) diagnosed clinically and radiologically as OA (osteoarthritis) were studied by obtaining fat-suppressed MR images of the knee. On 27 knees out of the 88, moreover, macroscopic observation was performed to make a comparative study between the directly-observed findings and MR findings. Fat-suppressed MR images were obtained sagittally by 3D-FLASH (fast low angle shot) sequence. The examined regions consisted of the following 4 sites; the medial condyle of the femur, its lateral condyle, the medial condyle of the tibia, and its lateral condyle. The revealed conditions of the cartilage were morphologically classified into 4 Stages. The evidence of cartilage defect on MR images was most frequently found at the medial condyle of the femur, with the medial condyle of the tibia, the lateral condyle of the femur, and the lateral condyle of the tibia following in a less frequent order. Fat-suppressed MRI's sensitivity to cartilage defect against macroscopy was 94.5%, specificity 95.4%, and accuracy 95.2%. MR imaging using fat-suppression can reveal cartilaginous degeneration and defect so well that this technique provides an important indication for selecting a proper method of treatment.