UCL Discovery

Abstract

We present cadaver validation of a method that uses tracked ultrasound to instantiate and register 3D statistical shape models (SSMs) of 3 femurs and 2 pelves. The SSMs were generated directly from the deformation fields obtained from non-rigid registration of CT images to a single target CT image. Ultrasound images were obtained from three intact cadavers. These were used to instantiate the model by iteratively minimising the RMS distance between the model surface and the ultrasound-derived bone surface points. The RMS distance between the instantiated model surface and the CT-derived bone surface was less than 3.72 mm in the region of the femoral head and acetabulum. We conclude that SSMs of the femur and pelvis may be instantiated and registered to surgical space to within a clinically acceptable accuracy using intraoperative ultrasound. This potentially could reduce the invasiveness of orthopaedic procedures, and remove the requirement for a preoperative CT scan.