ROLE OF MRI T2 MAPPING IN ASSESSMENT OF ARTICULAR KNEE CARTILAGE IN OSTEOARTHRITIS

Background: T2 mapping of hyaline cartilage is an imaging technique for the qualitative and quantitative detection of the
cartilage providing convincing color mapping and quantitative detection of the cartilage mainly regarding architecture and changes in water content, proteoglycan, and collagen matrix ultra-structure associated with early cartilage degeneration.
Aim Of Work: This work aims at elucidating the role of MRI complementary T2 mapping in assessment of articular knee cartilage for improving sensitivity of early detection of Osteoarthritis. Also, compare the articular cartilage T2 relaxation values in normal subjects and patients with osteoarthritis. Patients And Methods: This prospective case-control study was
approved by the Ethical Committee of Scientific Research in Ain Shams University, and the informed consent was obtained. The material of this study included sixty (60) subjects, divided into two groups, 50 patients (symptomatic group: 33 men and 17 women) with clinical evidence of osteoarthritis, and 10 normal control group (asymptomatic group 8 men and 2 women) were included in this study, with their ages ranged between 19-75 years. All patients and controls underwent MR imaging of the knee joint. MR imaging was performed at 1.5 Tesla by using a routine protocol with the addition of a sagittal, coronal, or axial T2 mapping sequence or all. The standard imaging planes of the knee were evaluated with articular cartilage assessment as intact or not. Thereafter, these standard planes were evaluated together with T2 maps and articular cartilage was again assessed as of normal (<48ms) or elevated (≥48ms) T2 value in terms of milliseconds. Generalized estimating equation models were used to compare the sensitivity and specificity of the routine MR imaging protocol and T2 maps. Results: Both sensitivities and specificities were 82% and 100%, respectively, for the routine MR protocol alone and 100% and 90% after the addition of the T2 mapping to the routine MR protocol. The addition of T2 maps to the routine MR imaging protocol significantly improved the sensitivity (Binary Diagnostic test, p = 0.01). A
Comparison between patients and controls as regards T2 values showed a highly statistically significant difference (Independent TTest, P<0 .001). Conclusion: A combination of both morphological and T2 mapping MRI, together with clinical evaluation represents a desirable multi-modal approach to the diagnosis of osteoarthritis. T2 mapping, as a biochemically sensitive MRI sequence of the knee improves sensitivity from 82% to 100% to detect early structural degeneration with better diagnostic information in the knee articular cartilage.