Novel Hip MRI Sequence Provides Consistent Osseous Morphology Dimensions for FAI Evaluation Compared With CT

Area of Science:

• Orthopaedic Surgery
• Radiology
• Medical Imaging

Background:

• Computed tomography (CT) is traditionally used for imaging femoroacetabular impingement (FAI) osseous morphology but involves ionizing radiation.
• Novel MRI protocols are being investigated as radiation-free alternatives for FAI assessment.
• The reliability of in- and out-of-phase MRI sequences for evaluating acetabular version in FAI has not been well-established compared to CT.

Purpose of the Study:

• To assess the reliability of acetabular version measurements using in- and out-of-phase MRI compared to CT.
• To compare hip morphometric measurements from routine MRI sequences with those from hip-specific CT.

Main Methods:

• Retrospective review of 95 patients (100 hips) diagnosed with FAI who underwent both hip-specific CT and in- and out-of-phase MRI.
• Fellowship-trained musculoskeletal radiologists retrospectively recorded morphometric measurements from radiology reports.
• Statistical analysis using intraclass correlation coefficients (ICCs) and t-tests to determine intermodality agreement.

Main Results:

• In- and out-of-phase MRI demonstrated moderate to good reliability (ICCs 0.62-0.80) for acetabular version measurements compared to CT.
• Routine MRI sequences showed poor to moderate agreement (ICCs 0.41-0.73) for other morphometric measurements when compared to CT.
• The in- and out-of-phase MRI protocol showed reliable agreement with CT for acetabular version.

Conclusions:

• In- and out-of-phase MRI protocols offer moderate to good reliability for evaluating acetabular version in FAI, comparable to CT.
• These MRI sequences can effectively assess hip osseous and soft tissue morphology, potentially reducing reliance on CT.
• Surgeons may consider selective use of CT for FAI evaluation, with future research exploring additional MRI sequences.