(A) fast 3D medical image registration algorithm and its application to digital subtraction CT angiography

Abstract

A novel method for fast, automatic 3D digital subtraction CT angiography (DS-CTA) is presented to generate artifact-free angiograms. The proposed method consists of two steps: 3D registration to align a CT image to the CT angiography (CTA) image and subtraction-and-refinement to extract blood vessels only. For efficient and accurate 3D registration in the first step, an NMI (normalized mutual information) based algorithm is adopted, and its fast version is developed by introducing a new measure. To further improve the subtracted image quality in the second step, a novel 3D refinement algorithm is suggested to effectively remove unwanted residuals. Experimental results of seven clinical CT/CTA head datasets demonstrate that cerebral vessels are well extracted from CTA images with almost no loss. The typical processing time is 3-9 minutes depending on the image size in a PC with a 2.4GHz CPU.