Preliminary study of lateral cerebral angiography with reverse rotation in the digital image registration and subtraction

Abstract

Objective Investigate the value and feasibility of image registration with reverse rotation in lateral cerebral DSA.Methods ( 1 ) Experimental study:the target images were subtracted directly,and subtracted again after reverse rotation.Software of registration and subtraction with reverse rotation edited by the author utilizing Visual Basic.The function of the automatic angle detection by the software were evaluated to see whether it detected the angle of line.The subtraction function of DSA by the software was evaluated.(2) Clinical retrospective study:the untreated mask and target inages of 15 patients with motion along vertical axis during lateral cerebral DSA were uploaded to the software.The target images were processed with and without the software to get two sets of images.( 3 ) Evaluation:four experienced radiologists read and compared the two sets of the images,and graded their findings.Results ( 1 ) The automatic detection by the software suggested that the target images should be rotated counterclockwise 1.3°. The subtraction result of the software was satisfactory.(2)In the 15 sets of images,there were only three sets of images deemed optimal after traditional subtraction.After reverse rotation,artifacts were significantly reduced and the image sharper. There were ten cases with significant artifacts after traditional subtraction,and those images were sharper and showed more peripheral vessels after reverse rotation. The traditional subtraction images of two sets could not be interpreted,the reverse rotation registration images reached the diagnostic quality.(3)Subjective evaluation: there were more information and less noise and distortion in the registration images with reverse rotation than in the traditional subtraction. But the image resolution decreased slightly after reverse rotation registration.Conclusion The registration of digital angiography with reverse rotation can improve the image quality in lateral cerebral DSA. Key words: Angiography,digital subtraction ; Comparative study ; Cerebral angiography