| OCR Text |
Show 40 flows within the veins and arteries to capture the image, so we cannot extract data for single vessels as can be done by selective dye release from a catheter in traditional angiography. Matte volumes provide the interactive tools to extract single vessels through the volume seedling approach. Different matte volumes can be used as priority functions for seedling growth to extract the vascular structure from complex volume data. Matte volumes present some preliminary techniques to overcome difficulties arising due to noisy data capture and vessel drop outs in the MRA process. Images generated with our volume exploration and visualization system for complex vascular data provide more visual information than those generated with plain volume rendering. Dr. David J. Fillmore[9] has done a comparison of Maximum Intensity Projection( MIP) technique and the volume rendering done by IVES for evaluation of renal artery anatomy in patients with Abdominal Aortic Aneurysm(AAA). MOTSA MRA data-sets obtained on 15 patients with AAA were reprojected with maximum intensity projection and volume rendering(VR). The VR technique used volume seedlings to emphasize connected structures such as the aorta and renal arteries thus eliminating background noise and overlying anatomy from the reprojected images. The resulting images were scored for renal artery and AAA visualization. With the volume seedling approach, visualization of renal artery anatomy and/ or AAA was rated equivalent or superior to the MIP algorithm in 12 of 15(80%) of cases. Depth cueing and superior noise and soft tissue suppression, were principally responsible for the better visualization. Computer Aided Tomography data also render themselves quite amenable to the volume exploration and visualization system. 5.2 Current Status The volume exploration and visualization system currently consists of an Isosurface Renderer, Slicer, Opacity Map editor, Color Map editor, Volume Renderer along with matte volume generators, Volume Seeds and Volume Seedlings and its various priority functions, and Batch Renderer. Supporting tools consist of a |
