Objectives: To investigate the value of diffusion tensor imaging (DTI) of articular cartilage to differentiate healthy from osteoarthritis (OA) subjects in all cartilage regions.
Methods: DTI was acquired sagittally at 7 T in ten healthy and five OA (Kellgren-Lawrence grade 2) subjects with a line scan diffusion tensor sequence (LSDTI). Three healthy volunteers and two OA subjects were examined twice to assess the test-retest reproducibility. Averaged mean diffusivity (MD) and fractional anisotropy (FA) were calculated in each cartilage region (femoral trochlea, lateral and medial femoral condyles, patella, and lateral and medial tibia).
Results: The test-retest reproducibility was 2.9% for MD and 5.6% for FA. Averaged MD was significantly increased (+20%, p < 0.05) in the OA subjects in the lateral femoral condyle, lateral tibia and the femoral trochlea compartments. Averaged FA presented a trend of lower values in the OA subjects (-12%), which was only significant for the lateral tibia.
Conclusions: In vivo DTI of articular cartilage with coverage of all cartilage regions using an LSDTI sequence is feasible, shows excellent reproducibility for MD and FA, and holds potential for the diagnosis of OA.
Key points: • DTI of articular cartilage is feasible at 7 T in all cartilage regions • DTI of articular cartilage can potentially differentiate healthy and OA subjects.