Magnetic resonance imaging in pathologic conditions of knee

Objective: To study MR appearances in various conditions affecting the knee and to identify the common lesions. Materials and methods: One hundred and fifteen patients with knee complaints and suspected to have meniscal, ligamentous or other pathology were studied using Signa contour 0.5 T (GE) MR machine. Images were obtained in sagittal, axial and coronal planes using SE, FSE, GRE and STIR sequences. Slice thickness of 4mm, FOV of 17 × 17 cm & 192 × 160 matrix were used. Results: Anterior cruciate ligament (ACL) tears accounted for the major cases (36.5%) followed by Medial meniscal tear (MM) (36.5%) and Lateral meniscal tear (17.3%). Hyperintensity, discontinuity and nonvisualisation were primary signs of ACL tear. Secondary signs like Posterior cruciate ligament (PCL) buckling, PCL index of >0.5 and uncovered lateral meniscus (LM) were also noted in certain areas. Meniscal tears seen commonly are grade III in medial meniscus and Grade I in lateral meniscus. Cases of meniscal cyst, synovial chondromatosis, quadriceps tendon tear, osteochondritis dissecans are clearly demonstrated on MR scans. The exact extent of the tumor in the marrow and soft tissues and involvement of joint space was demonstrated with great degree of accuracy. Conclusions: MR imaging of knee is an excellent modality that detects lesions not evident on arthroscopy and helps in planning the treatment of meniscal and ligament injuries. It demonstrates extent of marrow and soft tissue involvement of tumors with great degree of accuracy.