Automated bone contour detection in ultrasound B‐mode images for minimally invasive registration in computer‐assisted surgery—an in vitro evaluation

Abstract

Minimally invasive surgical interventions performed using computer-assisted surgery (CAS) systems require reliable registration methods for pre-operatively acquired patient anatomy representations that are compatible with the minimally invasive paradigm. The use of brightness-mode ultrasound seems to be promising, if associated devices work in a computationally efficient and fully automatic manner. This paper presents a rapid and fully automatic segmentation approach for ultrasound B-mode images capable of detecting echoes from bony structures. The algorithm focuses on the precise and rapid detection of bone contours usable for minimally invasive registration. The article introduces the image-processing scheme and a set-up enabling a direct comparison between manually digitized reference points and the segmented bone contours. The segmentation accuracy was assessed using cadaveric material. The experimental evaluation revealed results in the same order of magnitude as a pointer-based surface digitization procedure. The suggested segmentation approach provides a reliable means of detecting bony surface patches in ultrasound images.