MRI appearance of the articular cartilage in the knee according to age

To study the MR appearance of knee joint hyaline cartilage according to age, sex and body weight 120 subjects underwent MRI of the knee. Axial SE PD and T2, GE T1 and GE-MTC sequences, as well as coronal SE T1 and sagittal SE PD and T2 sequences were used. Thickness, surface, signal intensity and visibility of the patellar and femorotibial cartilages were investigated. As for cartilage thickness, a statistically significant difference was found between males and females in nearly all the measurement sites, the mean values being always higher in males. A statistically significant inverse correlation was found in males only, at the three load bearing regions of the medial femoral condyle. No significant correlation was demonstrated between the surface, the signal intensity and the trilaminar appearance of the cartilage and age, as well as body weight. The cartilage of the femoral condyles, the tibial plateaux and the patella showed a regular surface in 76%, 98% and 82% of cases respectively. The signal intensity was homogeneous in 88%, 98% and 82.5% of the cases. Mild focal inhomogeneities were seen in few cases. The visibility rate of the trilaminar appearance of cartilage was 85% for the femoral condyles, 70% for the patella, 13.5% for the tibial plateaux. GE sequence was the best sequence to evaluate cartilage thickness and signal intensity, while SE T2 sequence was the best sequence to depict the articular surface and, together with PD SE sequence, to visualize the trilaminar structure. The most relevant result of this study is the inverse correlation between cartilage thickness and age as well as body weight, mainly in males, in the three areas of greatest load (medial femoral condyle).