Takeshi Nakaura MD, Presenter: Nothing to Disclose

Satoru Oishi PhD, Abstract Co-Author: Nothing to Disclose

Osamu Ikeda MD, Abstract Co-Author: Nothing to Disclose

Shigehiko Katsuragawa PhD, Abstract Co-Author: Nothing to Disclose

Kazuo Awai MD, Abstract Co-Author: Nothing to Disclose

Yasuyuki Yamashita MD, Abstract Co-Author: Nothing to Disclose

To evaluate the efficacy of a new automatic remasking technique for non-breath hold digital subtraction angiography (DSA) using cross-correlation coefficient of ROIs.

We examined eight series of seven patients with liver tumors who could not hold their breath. Each patient underwent non-breath-hold intra-arterial DSA of the liver. Mask images were obtained 15 frames per second for 5 seconds and live images were obtained 3-4 images per second. After examination, image data was transferred to a personal computer and subtraction was performed using a selected mask image. Our new remasking technique automatically selected ROIs and decided the mask image by evaluating similarity in shape using a cross-correlation coefficient of ROIs. Three radiologists visually compared the images generated by the conventional subtraction technique and the new subtraction technique. Furthermore, they evaluated artifacts by calculating summation of negative value pixels of conventional and remasked DSA images.

In all series (100%), all radiologists judged the images processed with the new method to be better in quality. Negative value pixels were decreased to 4- 59 % (average, 28 %) on conventional DSA images. Arteries and tumor stains near the diaphragmatic surface were clearly visualized in images processed by the new method, however, artifacts near the intestinal tract were not reduced by this technique.

Our remasking method was a simple and effective method to reduce misregistration artifacts in DSA.

S.O.: Satoru Oishi is a employee of TOSHIBA MEDICAL SYSTEMS CORPORATION.

Nakaura, T, Oishi, S, Ikeda, O, Katsuragawa, S, Awai, K, Yamashita, Y, A New Technique for Reducing Misregistration Artifacts in Non-Breathhold Digital Subtraction Angiography: Automatic Remasking Technique Using Cross-correlation Coefficient of ROIs.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4413972.html