Non invasive ultrasound-based bone tracking

Abstract

International audienceIn the field of computer assisted orthopaedic surgery (CAOS), the motion of bones is generally tracked using a three-dimensional position measurement system. This is typically carried out by invasively attaching a marker to the bone. This is performed by inserting pins or screws, creating holes and causing trauma to the tissue and structure. This may increase the risk of bone fracture, infection and cause extra pain owing to extra inscisions. The development of 3D ultrasound (US) offers interesting prospects for surgical navigation. Indeed, this non-invasive data and real-time imaging technology could reduce the invasiveness of CAOS by replacing the optical trackers which are currently used. This implies the development of a method for rigid registration in order to track a bony structure. This method has to be at the same time robust and real-time. However, due to speckle, shadowing effects and the poor quality of US images, the registration of this imaging modality is a challenging process. The approach we develop consists in registering a reference 3D US volume to real time 4D US orthogonal slices. Since little information is present in these 4D images and to maximize their overlap to the reference volume, an initial stage consists in building a panoramic reference volume by registering overlapping 3D US volumes. This paper describes the registration method and the evaluation of the algorithm