Development of a Registration Technique with Nonlinear Geometric Warping in DSA Images
Yasuhiro Nishimoto, Masato Tanaka, Tetsuya Fukushima, Hiroyuki Sashie, Tomokazu Ishida, Hiroyuki Komuro, NOBUHSIGE HAYASHI, Norihiro Sadatou, Yasushi Ishii, Tamami Makino, Hisakazu Ogura · Japanese Journal of Radiological Technology · 1997
Misregistration artifact is the major cause of image degradation in digital subtraction angiography(DSA). As three-dimensional movement of the body causes uneven misregistration on two-dimensional images, conventional linear correction is not sufficient. We developed a nonlinear geometric warping technique. Using a local least-square matching method, we obtained the shift values sampled at 49 reference points in a 512×512 matrix. They were then fitted to the spline function to calculate pixel-by-pixel shift values. With these values, nonlinear geometric warping of the mask image followed. As a result, misregistration artifact was almost non-existent in the processed images, and vascular anatomy was clearly delineated even in the skull base region. This newly proposed method is a simple, practical way to reduce misregistration artifacts in DSA.