Simultaneous Bilateral T₁, T₂, and T_1ρ Relaxation Mapping of Hip Joint With 3D-MRI Fingerprinting

Area of Science:

• Radiology
• Biomedical Engineering
• Medical Imaging

Background:

• Three-dimensional MR fingerprinting (3D-MRF) is emerging for knee cartilage degeneration assessment.
• Adapting 3D-MRF for hip joint imaging presents unique challenges.
• This study explores 3D-MRF for hip joint cartilage evaluation.

Purpose of the Study:

• To establish the feasibility and repeatability of 3D-MRF for bilateral hip joint mapping.
• To quantitatively map proton density (PD), T1, T2, T1ρ, and ΔB1+ parameters.
• To achieve this within clinically practical scan times.

Main Methods:

• A prospective study involving eight healthy subjects and four patients with hip osteoarthritis (OA) and/or femoral acetabular impingement (FAI).
• Utilized a 3D-MRF sequence at 3T for bilateral hip joint mapping.
• Compared 3D-MRF with reference sequences (VIBE, TFL) and employed statistical tests (Regression, Bland-Altman, Kruskal-Wallis, Wilcoxon) for analysis.

Main Results:

• The 3D-MRF sequence achieved high signal-to-noise ratio (SNR) and low test-retest variability (T1: 3.36%, T2: 3.99%, T1ρ: 5.93%) within 15 minutes.
• Mild hip OA patients showed significant elevations in T2 (29.4 ± 9%) and T1ρ (32.4 ± 4.4%) in the femoral lateral compartment compared to healthy controls.
• Accuracy, repeatability, and subregional variations were assessed.

Conclusions:

• 3D-MRF demonstrates feasibility for simultaneous, quantitative cartilage mapping of the bilateral hip joint.
• This technique holds promise for evaluating cartilage in both healthy individuals and patients with mild OA.
• The quantitative parametric maps can potentially differentiate between healthy and degenerated hip cartilage.