3-D visualization of the newborn's hip joint using ultrasound and automatic image segmentation.

Graf's method has been established as a standardized procedure for the diagnostic screening of developmental dysplasia of the hip in newborns. In this procedure, a two dimensional ultrasound image that has to contain standardized landmarks is taken and evaluated interactively to calculate congruence indicators. Since these indicators are only derived from a 2-D scan, they do not reflect the spatial joint structure. In our study, we visualized three dimensional scans of newborns' hip joints that were obtained using a conventional ultrasound transducer and a commercial localizer system that was fixed to the scanhead. The landmarks were detected by automatic image segmentation to avoid examiner dependent findings. The landmark structures as well as an automatically determined virtual sphere approximating the femoral head were visualized color coded on a computer screen. This kind of visualization was found to be intuitive. The evaluation of the entire joint geometry and the 3-D relations between the acetabulum and the femoral head improves the reliability of the diagnostics.