Utility of radial reformation of three-dimensional fat-suppressed multi-echo gradient-recalled-echo images for the evaluation of acetabular labral injuries and femoroacetabular impingement

Abstract

Objectives: To assess the utility of the radial reformation of three-dimensional fat-suppressed multi-echo gradient-recalled-echo (3D FS me-GRE) for evaluating acetabular labral injuries and femoroacetabular impingement (FAI). Materials and methods: A total of 25 patients with suspected acetabular labral injuries were examined using 3D FS me-GRE and radial 2D T2*-weighted imaging (T2*WI) on a 3-T magnetic resonance imaging (MRI) scanner. The range of acetabular labral injuries was evaluated by radial reformation through the center of the acetabulum perpendicular to the plane across the entire acetabular rim (type 1 radial reformation) of 3D FS me-GRE and radial 2D T2*WI. To evaluate the FAI morphology, we performed radial reformation perpendicular to the central axis of the femoral head and neck (type 2 radial reformation) of 3D FS me-GRE. Results: Acetabular labral injuries were identified in 23 patients, and no acetabular labral injury was seen in two patients on type 1 radial reformation of 3D FS me-GRE and radial 2D T2*WI. The diagnostic concordance rate for the range of acetabular labral injuries between the two imaging methods was 76.0%, and there was excellent agreement for the injured angles (r = 0.977, p < 0.001). FAI morphology could be evaluated in all patients (no FAI, n = 8; cam, n = 10; pincer, n = 4; combined cam and pincer, n = 3) using type 2 radial reformation of 3D FS me-GRE. Conclusions: Type 1 and type 2 radial reformations of 3D FS me-GRE imaging were useful for evaluating acetabular labral injuries and determining whether patients with acetabular labral injuries have FAI, respectively.