Simultaneous Bilateral T, T, and T Relaxation Mapping of Hip Joint With 3D-MRI Fingerprinting.

BACKGROUND

Three-dimensional MR fingerprinting (3D-MRF) has been increasingly used to assess cartilage degeneration, particularly in the knee joint, by looking into multiple relaxation parameters. A comparable 3D-MRF approach can be adapted to assess cartilage degeneration for the hip joint, with changes to accommodate specific challenges of hip joint imaging.

PURPOSE

To demonstrate the feasibility and repeatability of 3D-MRF in the bilateral hip jointly we map proton density (PD), T, T, T, and ∆B in clinically feasible scan times.

STUDY TYPE

Prospective.

SUBJECTS

Eight healthy subjects, three patients with mild osteoarthritis (OA), and one of the OA patients had femoral acetabular impingement (FAI). A National Institute of Standards and Technology/International Society for Magnetic Resonance in Medicine (NIST/ISMRM) system phantom was also used.

FIELD STRENGTH/SEQUENCE: 3 T, 3D-MRF sequence for bilateral hip joint mapping. Reference sequences include Volume Interpolated Breath-hold Examination (VIBE) for T mapping, and magnetization-prepared fast low-angle shot (TFL) for T and T mapping.

ASSESSMENT

The signal-to-noise ratio (SNR), repeatability, scan time, and accuracy of T, T, and T maps of 3D-MRF sequence were evaluated on a NIST/ISMRM phantom and human subjects. Differences in the parametric maps between OA and healthy subjects were assessed.

STATISTICAL TESTS

Regression, Bland-Altman, Kruskal-Wallis, and Wilcoxon tests were used to assess for accuracy, repeatability, and subregional variation. The P-value <0.05 indicated statistically significant.

RESULTS

A 3D-MRF sequence sensitive to PD, T, T, T, and ∆B within 15 minutes, achieving high SNR and low test-retest coefficient of variance (T: 3.36%, T: 3.99%, T: 5.93%). Mild hip OA patients, including one with mild OA and FAI, showed elevation of 29.4 ± 9% (T) and 32.4 ± 4.4% (T) in femoral lateral compartment of the hip joint compared to healthy controls.

DATA CONCLUSION

3D-MRF may be a feasible approach for simultaneous, quantitative mapping of bilateral hip joint cartilage in healthy and mild OA patients.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 1.