Can T1-rho MRI detect acetabular cartilage degeneration in femoroacetabular impingement? A PILOT STUDY

Advanced MRI cartilage imaging such as T-1-rho (T1 rho) for the diagnosis of early cartilage degradation prior to morpholgic radiological changes may provide prognostic information in the management of joint disease. This study aimed first to determine the normal T1 rho profile of cartilage within the hip, and secondly to identify any differences in T1 rho profile between the normal and symptomatic femoroacetabular impingement (FAI) hip. Ten patients with cam-type FAI (seven male and three female, mean age 35.9 years (28 to 48)) and ten control patients (four male and six female, mean age 30.6 years (22 to 35)) underwent 1.5T T1 rho MRI of a single hip. Mean T1 rho relaxation times for full thickness and each of the three equal cartilage thickness layers were calculated and compared between the groups. The mean T1 rho relaxation times for full cartilage thickness of control and FAI hips were similar (37.17 ms (SD 9.95) and 36.71 ms (SD 6.72), respectively). The control group demonstrated a T1 rho value trend, increasing from deep to superficial cartilage layers, with the middle third having significantly greater T1 rho relaxation values than the deepest third (p = 0.008). The FAI group demonstrated loss of this trend. The deepest third in the FAI group demonstrated greater T1 rho relaxation values than controls (p = 0.028). These results suggest that 1.5T T1 rho MRI can detect acetabular hyaline cartilage changes in patients with FAI.