rho Relaxation of Talar Cartilage with and without Axial Loading in Situ: An Indicator of Early Degenerative Changes in Individuals with Chronic Ankle Instability?

Presentation Format Scientific poster presentation.

Purpose or Learning Objective To evaluate T1rho relaxation times of talar cartilage as an indicator for early degenerative changes in individuals with mechanical chronic ankle instability (CAI) and healthy controls (HCs) with and without axial loading during magnetic resonance imaging (MRI) acquisition.

Methods or Background Individuals with CAI (n = 10) and HCs (n = 17) underwent 3-T MRI of the ankle with and without axial loading of 500 N in situ applied by a custom-built ankle arthrometer. T1rho relaxation time measurements of talar cartilage were performed using a three-dimensional fast low-angle shot sequence augmented with variable spin-lock preparation intervals (0/10/20/30/40 ms) and mono-exponential pixel-by-pixel T1rho fitting. Six talar cartilage regions of interest (ROIs) were manually segmented (medial, lateral, anteromedial, anterolateral, posteromedial, and posterolateral). Median T1rho values, as well as changes between no loading and loading, were compared using the Mann-Whitney U test.

Results or Findings Age was 22.5 ± 3.1 years (mean ± standard deviation; 20 women and 7 men). No morphological cartilage defects were depicted on morphological MRI.

Without axial loading, median T1rho relaxation times of talar cartilage were significantly higher in all talar ROIs for the CAI group compared with the HC group except for the posterolateral ROI (lateral U = 44.0, p = 0.04, r = 0.4; medial U = 34.0, p = 0.01, r = 0.5; anterolateral U = 41.0, p  = 0.027, r = 0.4; anteromedial U = 33.0, p  = 0.009, r = 0.5; and posteromedial U = 36.0, p  = 0.013, r = 0.5).

With axial loading, no significant differences of median T1rho relaxation times of talar cartilage were observed between the CAI group and the HC group, although the CAI group still showed higher T1rho relaxation times in all ROIs (p > 0.05).

In both groups, no significant differences were found between median T1rho relaxation times with and without axial loading (p > 0.05).

Conclusion Patients with chronic ankle instability show significantly increased T1rho relaxation times of talar cartilage, indicating early cartilage matrix degeneration. However, lack of differences of T1rho relaxation times between groups with axial loading may indicate maintained cartilage shock-absorbing function at this early time point, where no morphological changes were detected. Thus preventive measures may still be effective to halt progression of ankle joint degeneration.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
03 June 2021