Fast Registration of CT with Intra-operative Ultrasound Images for Spine Surgery

摘要

Intra-operative ultrasound (iUS) has a considerable potential for image-guided navigation in spinal fusion surgery. Accurate registration of pre-operative computed tomography (CT) images to the iUS images is crucial for guidance. However, low image quality and bone-related artifacts in iUS render the task challenging. This paper presents a GPU-based fast CT-to-iUS rigid registration framework of a single vertebra designed for image-guided spine surgery. First, the framework involves a straightforward iUS acquisition procedure consisting in a single sweep in the cranio-caudal axis, which allows to roughly determine the initial alignment between CT and iUS images. Then, using this as a starting point, the registration is refined by aligning the gradients that are located on the posterior surface of the vertebra to obtain the final transformation. We validated our approach on a lumbosacral section of a porcine cadaver with images from T15 to L6 vertebrae. The median target registration error was 1.48 mm (IQR= 0.68 mm), which is below the clinical acceptance threshold of 2 mm. The total registration time was 10.79s± 1.27 s. We believe that our approach matches the clinical needs in terms of accuracy and computation time, which makes it a potential solution to be integrated into the surgical workflow.