373 Tip AND T2 MAPPING OF THE PROXIMAL TIBIOFIBULAR JOINT WITH REGARD TO AGING AND CARTILAGE DEGENERATION

Purpose: Compare cartilage MR T1rho values of defined subcompartments in ACL-reconstructed knees with and without meniscal tears to the patient’s own contralateral, uninjured knee at 12 to 16 months after ACL-reconstructions. Methods: Nineteen patients’ knees with ACL injuries [10 females, mean age 37.4; 9 males, mean age 39.6) and their contralateral knees were studied. All patients had ACL reconstruction, 12 to 16 months after which patients were scanned. Meniscal tears of injured and uninjured knees were identified by chart review of each post-operative note and MRI. The imaging protocol included sagittal 3D fat-suppressed high-resolution spoiled gradient-echo (HR-SPGR) images and 3D quantitative T1ø mapping. The acquisition parameters for the sagittal 3D T1ø-weighted imaging sequence were TSL (time of spin-lock) = 0, 10, 40, 80ms, FSL = 500Hz. The T1ø map was reconstructed by fitting the T1øweighted images pixel-by-pixel to the equation: S(TSL) ∝ exp(−TSL/T1ø), and the reconstructed maps were subsequently registered to the previously acquired HR-SPGR images. Using an in-house developed program, the SPGR images were used to semi-automatically segment five compartments, the lateral/medial femoral condyles (LFC/MFC), the lateral/medial tibias (LT/MT) and the patella (Fig. 1A). The femoral condyles and tibias were divided into subcompartments with regard to the meniscus (Fig. 1B).