T2 values of posterior horns of knee menisci in asymptomatic subjects

Abstract

Purpose: The magnetic resonance (MR) T2 value of cartilage is a reliable indicator of tissue properties and therefore may be used as an objective diagnostic tool in early meniscal degeneration. The purpose of this study was to investigate age, gender, location, and zonal differences in MR T2 value of the posterior horns of knee menisci in asymptomatic subjects.

Methods: Sixty asymptomatic volunteers (30 men and 30 women) were enrolled and divided into three different age groups: 20-34, 35-49 and 50-70 years. The inclusion criteria were BMI<30 kg/cm(2), normalized Western Ontario and McMaster Universities (WOMAC) pain score of zero, and no evidence of meniscal and ligamentous abnormalities on routine knee MR imaging. The T2 values were measured on images acquired with a T2-weighted fat-suppressed turbo spin-echo sequence at 3T.

Results: The mean T2 values in both medial and lateral menisci for the 20-34, 35-49, and 50-70 age groups were 9.94 msec±0.94, 10.73 msec±1.55, and 12.36 msec±2.27, respectively, for women and 9.17 msec±0.74, 9.64 msec±0.67, and 10.95 msec±1.33, respectively, for men. The T2 values were significantly higher in the 50-70 age group than the 20-34 age group (P<0.001) and in women than in men (P = 0.001, 0.004, and 0.049 for each respective age group). T2 values were significantly higher in medial menisci than in lateral menisci only in women age 50-70 (3.33 msec, P = 0.006) and in the white zone and red/white zone of the 50-70 and 35-49 age groups than that of the 20-34 age group (2.47, 1.02; 2.77, 1.16 msec, respectively, all P<0.01).

Conclusion: The MR T2 values of the posterior meniscal horns increase with increasing age in women and are higher in women than in men. The age-related rise of T2 values appears to be more severe in medial menisci than in lateral menisci. Differences exist in the white zone and red/white zone.

Figure 1. Flowchart shows the process used to select and recruit subjects from the local community.

Figure 2. Representative ROIs in a nearly sagittal slice of a knee meniscus are shown.

The selection of ROIs was performed on the first-echo MR image, which is enlarged on the right side. The black arrows indicate the separation between the three zones, and each zone was about one-third the width of the meniscus.

Figure 3. T2 values of both menisci for three age groups of women and men.

In women, T2 values increase significantly from group 1 to group 3 (*P<0.001 as compared with group 1). Women show significantly greater T2 values than men in all three age groups (with P = 0.001, 0.004, and 0.049, respectively).

Figure 4. T2 values of the medial and lateral menisci in three age groups of women and men.

The T2 values of the medial meniscus for women increase significantly from group 1 to group 3 (*P<0.001 as compared with group 1). But the T2 values of the lateral meniscus for women and men were not significantly different among three age groups.

Figure 5. T2 values of the three zones in three age groups of women and men.

The differences in T2 values for the white zone and R/W zone in women and men are significantly greater between group 3 and group 1 and between group 2 and group 1 (*P<0.01) but no corresponding differences exist for the red zone in women and men.