Patient-specific 3D models created by 3D imaging system or bi-planar imaging coupled with Moiré–Fringe projections: a comparative study of accuracy and reliability on spinal curvatures and vertebral rotation data

PurposeThe aim of this study is to compare the accuracy and reliability of spinal curvatures and vertebral rotation data based on patient-specific 3D models created by 3D imaging system or by bi-planar imaging coupled with Moiré–Fringe projections.Methods and materialsSixty-two consecutive patients from a single institution were prospectively included. For each patient, frontal and sagittal calibrated low-dose bi-planar X-rays were performed and coupled simultaneously with an optical Moiré back surface-based technology. The 3D reconstructions of spine and pelvis were performed independently by one radiologist and one technician in radiology using two different semi-automatic methods using 3D radio-imaging system (method 1) or bi-planar imaging coupled with Moiré projections (method 2). Both methods were compared using Bland–Altman analysis, and reliability using intraclass correlation coefficient (ICC).ResultsICC showed good to very good agreement. Between the two techniques, the maximum 95 % prediction limits was −4.9° degrees for the measurements of spinal coronal curves and less than 5° for other parameters. Inter-rater reliability was excellent for all parameters across both methods, except for axial rotation with method 2 for which ICC was fair. Method 1 was faster for reconstruction time than method 2 for both readers (13.4 vs. 20.7 min and 10.6 vs. 13.9 min; p = 0.0001).ConclusionWhile a lower accuracy was observed for the evaluation of the axial rotation, bi-planar imaging coupled with Moiré–Fringe projections may be an accurate and reliable tool to perform 3D reconstructions of the spine and pelvis.