2D/3D registration of endoscopic ultrasound to CT volume data

Abstract

This paper describes a computer-aided navigation system using image fusion to support endoscopic interventions such as the accurate collection of biopsy specimens. An endoscope provides the physician with real-time ultrasound (US) and a video image. An image slice that corresponds to the corresponding image from the US scan head is derived from a preoperative computed tomography (CT) or magnetic resonance image volume data set using oblique reformatting and displayed side by side with the US image. The position of the image acquired by the US scan head is determined by a miniaturized electromagnetic tracking system (EMTS) after calibrating the endoscope's scan head. The transformation between the patient coordinate system and the preoperative data set is calculated using a 2D/3D registration. This is achieved by calibrating an intraoperative interventional CT slice with an optical tracking system (OTS) using the same algorithm as for the US calibration. The slice is then used for 2D/3D registration with the coordinate system of the preoperative volume. The fiducial registration error (FRE) for the US calibration was 2.0 mm +/- 0.4 mm; the interventional CT FRE was 0.36 +/- 0.12 mm; and the 2D/3D registration target registration error (TRE) was 1.8 +/- 0.3 mm. The point-to-point registration between the OTS and the EMTS had an FRE of 0.9 +/- 0.4 mm. Finally, we found an overall TRE for the complete system to be 3.9 +/- 0.6 mm.

Simultaneous Multi-Structure Segmentation and 3D Nonrigid Pose Estimation in Image-Guided Robotic Surgery

“…To fuse both modalities and assist the surgeon, numerous approaches have been proposed for augmenting the intraoperative view with 3D data obtained from preoperative scans, e.g. fusing 3D preoperative volume with 2D intraoperative US [3], [6], [7], [16], intraoperative MR [12], and 2D X-ray [24], [40] (Table I). Pose estimation (position, orientation and scale) is one of the main challenges in 2D slice to 3D volume registration.…”

“…Pose estimation (position, orientation and scale) is one of the main challenges in 2D slice to 3D volume registration. One way to overcome this challenge is to use external intraoperative markers and track them [15], [16]. However, the feasibility, TABLE I: Categorization and comparison of certain features (handling multiple 2D views, multiple objects segmentation, tissues occlusion, non-rigid tissues deformation, manual vs. automatic pose estimation, and camera parameter correction) between state-of-the-art methods and our proposed method.…”

Multi-Modality Imaging: A Software Fusion and Image-Guided Therapy Perspective

“…that acquire single slices are histology [96], Cine-MR [97] and conventional ultrasound [98,99]. It has to be said that multidimensional image registration is not multi-modal image fusion in a strict sense-yet the difference in image dimensionality makes it a special case worth mentioning.…”

Three-dimensional ultrasound scanning

“…Free-hand three-dimensional scanning with magnetic field sensors. The magnetic field sensors approach for free-hand three-dimensional US imaging has successfully been used in many diagnostic applications, including echocardiography, obstetrics and vascular imaging [3,4,[50][51][52][53][54][55][56][57][58][59][60]. This approach makes use of a conventional US transducer generating twodimensional US images.…”

“…Thus, metal hospital beds in procedure or surgical rooms can cause significant distortions. Modern magnetic field sensors make use of two approaches: an alternating magnetic field (Fastrak from Polhemus and the Aurora from Northern Digital) [4,50] and a pulsed magnetic field (Bird from Ascension) [3]. Although the use of both approaches can produce excellent three-dimensional reconstructions, the alternating magnetic field approach has been shown to be more sensitive to metallic objects owing to generation of eddy currents, and the pulsed magnetic field approach has been shown to be more sensitive to ferromagnetic objects.…”