T2- mapping of articular cartilage of the knee joint in healthy volunteers: standard values and reproducibility of measurements

Objective: to measure the absolute values of the T2 relaxation time in different segments and zones of the articular cartilage of the knee joint in healthy volunteers using an MRI scanner with a magnetic field induction of 3.0 T, followed by an assessment of the reproducibility of measurements. Materials and methods. 20 healthy volunteers aged 21 to 32 years were examined. Magnetic resonance imaging of the knee joints was performed in all patients with the inclusion of T2 color mapping sequences in the axial and sagittal planes. Knee joint segmentation was performed according to WORMS with an assessment of the absolute values of T2 relaxation time in the basal, intermediate and superficial zones of articular cartilage. The reproducibility of measurements of T2 relaxation time between observers was estimated using the intraclass correlation coefficient ICC (2,k). Results. A regular increase in the time of T2 relaxation from the basal to the surface zone of cartilage in most segments of the knee joint has been established. The highest values were recorded in the superficial zone of the articular cartilage of the femur, the lowest in the basal zone of the tibial cartilage. The ICC coefficients ranged from moderate to high levels of consistency depending on the cartilage zone and the anatomical segment of the joint. Conclusion. The obtained values of the T2 relaxation time in the cartilage of healthy volunteers can be used as a reference in the assessment of early degenerative changes in the articular cartilage of the knee joint. The high reproducibility of the results between observers confirms the reliability of the methodology while observing standardized measurement techniques. The most stable data were obtained in the anterior and central segments of the condyles of the femur and tibia of the knee joint, the posterior segments can be excluded from routine analysis.