C. Stotter (Krems, AT)
Danube-University Krems Center for Regenerative Medicine and OrthopedicsPresenter Of 1 Presentation
12.3.2 - Fully Automated Radiographic Measurements of The Pelvis
Abstract
Purpose
Pelvic radiographs help to evaluate geometry and morphometry of the hip joint. However, performing these measurements is not only a tedious, time-consuming task, but scientific literature also shows high inter- and intraobserver differences. Fully automated measurements could provide accurate, standardized and reproducible results more efficiently than the current radiological procedure.
Methods and Materials
AP pelvis radiographs of 62 patients (age: 36.9 ± 11.6 years; 34 female, 28 male) were included. Three orthopaedic surgeons independently performed the following measurements using an interactive planning software: Caput-collum-diaphyseal (CCD) angle, Lateral center-edge (LCE) angle, Tönnis angle, Sharp Angle and Extrusion index. The same images were also processed with a fully-automated, AI-based software (HIPPO, IBLab GmbH, Vienna). For hips with all three expert reads available (CCD: 119, LCE: 121, Other: 122), mean and standard deviation of the paired measurement differences was computed, comparing the averaged results of the expert readers (“mean-reader”) with HIPPO’s measurements as well as the expert readers against each other. An orthogonal linear regression was performed to assess proportional bias.
Results
Mean and standard deviation of the paired differences of “mean-reader” and HIPPO amounted to the following values (regression line slope in brackets): CCD: 0.22°±3.81° (1.03), LCE: -0.56°±2.99° (1.02), Tönnis: 1.52°±2.34° (0.94), Sharp: -0.92°±1.67° (0.97), Extrusion index: 2.08%±3.27% (1.14). Comparing “reader 1” and “reader 2” (most similar readers), yields the following: CCD: 0.58°±3.23° (0.91), LCE: -0.79°±2.16° (0.93), Tönnis: -0.93°±3.23° (1.19), Sharp: 0.76°±1.99° (1.00), Extrusion index: 0.22%±2.66% (0.91).
Conclusion
Regarding mean difference and regression line slopes, HIPPO’s performance is comparable to interobserver differences. Standard deviation shows increased variation of the paired differences, however, this is also true for inter-observer comparisons. These results indicate low absolute and proportional bias of HIPPO compared to expert readers. Automated radiographic analysis could therefore provide reproducible results for each AP pelvic image and help to identify radiographic signs of femoroacetabular impingement (FAI).