Introduction: Accurate three-dimensional visualization of the hip joint is essential for preoperative planning of complex orthopedic procedures such as periacetabular osteotomy (PAO), femoral osteoplasty, and acetabuloplasty. In addition to bony structures, the acetabular labrum plays an important biomechanical and stabilizing role, and magnetic resonance imaging (MRI) provides better visualization of the labrum than computed tomography (CT). One of the main challenges is the segmentation and registration of MRI-based labrum models into CT-based pelvic models. Purpose: The aim of this master’s thesis was to determine whether registration of the labrum into CT models of the pelvis is more accurate when the femoral head or the acetabulum is used as the reference structure. In addition, the feasibility of manual segmentation of the labrum from MRI data and the suitability of 3D Slicer for quantitative analysis of registrations were assessed. Methods: The study was based on retrospectively collected CT and MRI data of fourteen hips from eleven patients with developmental dysplasia of the hip (DDH) or femoroacetabular impingement (FAI). The labrum was manually segmented from multiple MRI sequences using Ekliptik EBS and registered into CT pelvic models with two different references (acetabulum and femoral head). Registration accuracy was evaluated using the Dice similarity coefficient, Hausdorff distance, and center displacement. The reproducibility of metric calculations in 3D Slicer was also tested. Statistical analysis was performed in IBM SPSS. Results: The mean Dice coefficient was 0.236 ± 0.139, Hausdorff distances were moderately high, and the average center displacement was approximately 3.6 mm. No significant differences in accuracy metrics were found between acetabulum- and femoral head–based registrations. The order of model input in 3D Slicer had no impact on the results. Discussion and conclusion: Segmentation of the labrum from MRI data proved feasible, and integration into CT models was technically achievable. The choice between acetabulum and femoral head as reference did not result in statistically significant differences, confirming that the main limitations arise from rigid registration methods applied to soft tissues. Additional visual validation and the development of non-rigid approaches are therefore recommended. The models are applicable for preoperative planning of corrective procedures, especially when supported by standardized imaging protocols and multiple observers.
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