MRI Findings of Pure Cartilage Injury of the Knee Joint

Objective To analyze MRI manifestations of pure cartilage injury of the knee joint, and to discuss the key points of imaging technique and the mechanism of injury. Materials and Methods Using EPI and GRE sequences, sagittal and axial MRI scanning was performed in 16 patients with painful knee joint and normal plain radiograph of knee joint. MRI signs were observed and analyzed. Results A total 24 morphologic or signal abnormalities were found in 16 cases, which included serrated surface of the cartilage, undulated defect of the cartilage or compressed cartilage. Abnormal stripe low-signal on EPI and slight high-signal on GRE were demonstrated. Conclusion Based on the injury severity, pure cartilage injury of the knee joint can be divided into three patterns: (1) abnormal signal with normal cartilage surface; (2) defect of cartilage surface in different degree; (3) totally compressed or destructed of the cartilage. MRI is the best non-invasive method for studying cartilage injury.