Age dependency of cartilage magnetic resonance imaging T2 relaxation times in asymptomatic women.

Abstract

Because the magnetic resonance imaging (MRI) transverse relaxation time (T2) of cartilage is sensitive to organization of collagen fibers in the cartilage, it may be a noninvasive image marker for senescent changes in cartilage collagen and early cartilage degeneration. The purpose of this study was to determine age-dependent differences in cartilage T2 values in healthy asymptomatic women. Quantitative T2 maps of patellar cartilage from 30 asymptomatic women ages 22-86 years were obtained using a 3.0T MRI scanner. The study population was stratified by age into 4 cohorts: 18-30, 31-45, 46-65, and 66-86 years. Spatial differences in cartilage T2 were determined as a function of normalized distance from bone. Older groups were compared with the 18-30-year-old group to determine the effects of age on cartilage T2 values. Regions were considered statistically significantly different if the mean T2 values between groups differed at P < 0.05. Mean cartilage T2 profiles were nearly identical for the 2 youngest cohorts. Compared with the 18-30-year-old group, T2 values were statistically significantly longer in the superficial 40% of cartilage in the 46-65-year-old group and over the entire cartilage thickness in the 66-86-year-old group. The location of T2 elevations in women over the age of 45 years is consistent with the theory that senescent changes of cartilage collagen begin near the articular surface and progress to the deeper cartilage with advancing age.