A novel mr‐based method for detection of cartilage delamination in femoroacetabular impingement patients

In this study, quantitative magnetic resonance based measurements were used to evaluate T1ρ and T2 mapping and heterogeneity in femoroacetabular impingement (FAI) patients with acetabular cartilage delamination and to determine the ability of these quantitative MR‐based measurements in detecting delamination. Unilateral hip joint MR‐scans of 36 FAI patients with arthroscopically‐confirmed acetabular cartilage delamination and 36 age, gender, and BMI matched controls were obtained. T1ρ and T2 mapping and heterogeneity of the hip joint articular cartilage were assessed in both groups using voxel‐based relaxometry (VBR). Quantitative MR‐based measurements were compared using statistical parametric mapping (SPM). Receiver operating characteristic (ROC) analysis was used to assess the ability of these quantitative measurements in detecting delamination by calculating the area under the curve (AUC). Pearson partial correlations (r) were used to assess for associations between T1ρ and T2 radial heterogeneity with the alpha angle in FAI patients. T1ρ and T2 global acetabular values were significantly higher in FAI patients with a focal increase within the posterior acetabular cartilage. FAI patients exhibited increased anterior superior acetabular T1ρ and T2 heterogeneity and both of these measures demonstrated a strong ability to detect acetabular cartilage delamination (T1ρ AUC: 0.96, p < 0.001; T2 AUC: 0.93, p < 0.001). FAI patients with a larger alpha angle exhibited increased anterior superior acetabular T1ρ (r = 0.48, p = 0.02) and T2 (r = 0.42, p = 0.03) heterogeneity. T1ρ and T2 heterogeneity within the anterior superior acetabular cartilage was shown to be a sensitive measure in detecting delamination and may prove beneficial to clinicians in determining optimal interventions for FAI patients. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:971–978, 2018.