MRI-based static and functional assessment of complex hip deformities in comparison with CT: a validation study

Area of Science:

• Orthopedic imaging
• Biomechanical analysis
• Medical diagnostics

Background:

• Accurate assessment of hip morphology and range of motion (ROM) is crucial for diagnosing and managing hip deformities.
• Computed tomography (CT) is considered the gold standard for these evaluations, but magnetic resonance imaging (MRI) offers advantages in soft tissue visualization.

Purpose of the Study:

• To investigate the agreement between quantitative hip morphology parameters derived from MRI and virtual ROM analysis compared to CT.
• To determine if MRI can be used as a substitute for CT in virtual ROM analysis.

Main Methods:

• Twenty patients with hip deformities underwent MRI, and various morphological parameters were measured.
• Virtual single and combined hip movements were simulated using motion analysis software.
• MRI findings were compared with CT results using statistical methods including intraclass correlation coefficient and Bland-Altmann plots.

Main Results:

• Near-perfect agreement (ICC > 0.95) was observed between MRI and CT for acetabular parameters like anteversion, sector angles, sourcil angle, and coverage.
• Femoral parameters showed almost perfect agreement, with the alpha angle being a minor exception.
• For virtual ROM analysis, impingement was detected by both CT and MRI in 18.6% of movements, with high concordance.

Conclusions:

• MRI-based assessment of hip morphology and virtual ROM analysis demonstrates good inter-method agreement with CT.
• MRI is a feasible and substantially equivalent alternative to CT for virtual ROM analysis, potentially reducing the need for CT scans.