Anatomical image-based rigid registration between fluoroscopic X-ray and
CT: methods comparison and experimental results

L. Joskowicz (1), D. Knaan (1), H. Livyatan (1), Z. Yaniv (1), 
A. Khoury (2), R. Mosheiff (2),M. Liebergall (2)

(1) School of Computer Science and Eng., The Hebrew Univ. of Jerusalem, Israel 
(2) Orthopaedic Surgery Dept., The Hadassah-Hebrew Univ. Medical School, Israel.

Abstract: 

This paper describes a practical, whole system approach to rigid
registration between preoperative CT and intraoperative X-rays obtained
with a tracked C-arm and demonstrates its efficacy experimentally.  Our
approach is generic, targeted to orthopaedic surgery and includes
fluoroscopic X-ray calibration, image distortion correction, optical
tracking, and 2D/3D image registration.  For 2D/3D image registration, we
use two new gradient-based and intensity-based algorithms which are fast,
robust, and accurate in realistic setups.  Our experiments on simulated,
in-vitro, and cadaver cases show that an overall mean target registration
error of 1--1.5mm (2mm worst case), which succeeds on the first try 95\% or
more of the time in less than two minutes, is practically feasible.

Keywords: 2D/3D rigid registration, X-ray to CT registration

Published in: Proc. of the 17th Int. Congress on Computer-Assisted
Radiology and Surgery, CARS'2003, H.U. Lemke et. al. editors, Elsevier
2003, pp 419--425.