# Vessel-based CTA-image to spatial anatomy registration using tracked catheter position data: preclinical evaluation of in vivo accuracy

## TL;DR

This study shows that preoperative CTA images can be accurately registered to a patient's vascular anatomy using tracked catheter data, reducing the need for intraoperative radiation.

## Contribution

A vessel-based registration method using tracked guidewire data achieves acceptable accuracy without external markers.

## Key findings

- The median 3D RMS registration error was 4.82 mm in preclinical testing.
- Vessel-based registration is feasible without external fiducial markers.
- The method shows potential to reduce ionizing radiation during vascular procedures.

## Abstract

Electromagnetic tracking of endovascular instruments has the potential to substantially decrease radiation exposure of patients and personnel. In this study, we evaluated the in vivo accuracy of a vessel-based method to register preoperative computed tomography angiography (CTA) images to physical coordinates using an electromagnetically tracked guidewire. Centerlines of the aortoiliac arteries were extracted from preoperative CTA acquired from five swine. Intravascular positions were obtained from an electromagnetically tracked guidewire. An iterative-closest-point algorithm registered the position data to the preoperative image centerlines. To evaluate the registration accuracy, a guidewire was placed inside the superior mesenteric, left and right renal arteries under fluoroscopic guidance. Position data was acquired with electromagnetic tracking as the guidewire was pulled into the aorta. The resulting measured positions were compared to the corresponding ostia manually identified in the CTA images after applying the registration. The three-dimensional (3D) Euclidean distances were calculated between each corresponding ostial point, and the root mean square (RMS) was calculated for each registration. The median 3D RMS for all registrations was 4.82 mm, with an interquartile range of 3.53–6.14 mm. A vessel-based registration of CTA images to vascular anatomy is possible with acceptable accuracy and encourages further clinical testing.

This study shows that the centerline algorithm can be used to register preoperative CTA images to vascular anatomy, with the potential to further reduce ionizing radiation exposure during vascular procedures.

Preoperative images can be used to guide the procedure without ionizing intraoperative imaging.Preoperative imaging can be the only imaging modality used for guidance of vascular procedures.No need to use external fiducial markers to register/match images and spatial anatomy.Acceptable accuracy can be achieved for navigation in a preclinical setting.

Preoperative images can be used to guide the procedure without ionizing intraoperative imaging.

Preoperative imaging can be the only imaging modality used for guidance of vascular procedures.

No need to use external fiducial markers to register/match images and spatial anatomy.

Acceptable accuracy can be achieved for navigation in a preclinical setting.