Hybrid 2D–3D ultrasound registration for navigated prostate biopsy

Abstract

Purpose: We present a hybrid 2D-3D ultrasound (US) rigid registration method for navigated prostate biopsy that enables continuous localization of the biopsy trajectory during the exam.Methods: Current clinical computer-assisted biopsy systems use either sensorbased or image-based approaches. We combine the advantages of both in order to obtain an accurate and real-time navigation based only on an approximate localization of the US probe. Starting with features extracted in both 2D and 3D images, our method introduces a variant of the Iterative Closest Point (ICP) algorithm. Among other differences to ICP, a combination of both the euclidean distance of feature positions and the similarity distance of feature descriptors is used to find matches between 2D and 3D features. The evaluation of the method is twofold. First, an analysis of variance on input parameters is conducted to estimate the sensitivity of our method to their initialization. Secondly, for a selected set of their values, the Target Registration Error (TRE) was calculated on 29,760 (resp. 4,000) registrations in two different experiments. It was obtained using manually identified anatomical fiducials.Results: For 160 US volumes, from 20 patients, recorded during routine biopsy procedures performed in two hospitals by 6 operators, the mean TRE was 3.91±3.22 mm (resp. 4.37±2.62 mm).Conclusion: This work allows envisioning further developments for prostate navigation and their clinical transfer.

Towards real‐time free‐hand biopsy navigation

“…The following sections provide information about the different steps of the registration method. We invite the interested reader to refer to [10] where different solutions and their parametrizations have been studied and are presented in full details.…”

“…In order to improve the seminal work proposed by Selmi [10], we have introduced a multi-resolution approach to the orignal workflow. Multi-resolution approaches are used to obtain more precise and accurate results with a generally better computation time.…”

“…This selection is based on a fixed rejection rate of the worst pairs and requires implementing an efficient sorting method with respect to the similarity values. Conversely to [10] where this rejection rate was not used because of its computational cost, the current implementation makes efficient use of a sorted multi-set container of C++. Such special container can support multiple elements with the same similarity value while maintaining an insertion rate with a logarithmic complexity.…”

“…Here, the objective is to explore in a systematic way the limits of the presented approach on static 2D/3D registrations. This first evaluation is intended to show, in a direct way, the effect of the additions we made to [10]. The following section presents the details of this benchmark.…”

“…To alleviate these constraints, our team [10] has proposed a different organ-based approach to achieve real-time registration on a standard CPU without the need for a passive arm. This method can be seen as a variant of the iterative closest point method (ICP).…”