| An integrated approach is developed for 3D cone beam reconstruction of cerebral vasculature (both morphology and gray scale) from a limited number (4-6) of digital subtraction angiographic (DSA) projections, obtained using a standard biplane C-arm x-ray system. This provides an visualization tool for evaluating vascular relationships by the surgeons and neuroradiologists, in addition to quantification of stenoses and aneurysm sizes.;Problems in using ART in this work are evaluated by comparing reconstructions from experimentally obtained and idealized projection data. Limited view reconstruction method is demonstrated to be unstable. In addition, errors arising from geometric uncertainty, noise, and partial voluming are assessed with simulations. Corrective measures in reconstruction are described and demonstrated with experimental data.;Reconstruction of a phantom containing fiducial markers at known locations demonstrated that the reconstructed geometry is accurate to less than a pixel width (0.23 mm). The reconstruction algorithm with corrective measures is tested using (i) a high contrast thin wire phantom, (ii) an anatomic skull phantom with an embedded cerebral vasculature reproduction that includes an aneurysm, (iii) a human carotid artery, and (iv) a human cerebral vasculature with an aneurysm. The use of weight norm cut off and averaging ART for different terminal conditions is found to be effective with clinical data reconstructions. The reconstruction results validated by comparing experimental projections with reprojections of the 3D reconstruction gives encouraging results.;The reconstruction is performed iteratively using Algebraic Reconstruction Technique (ART) with non-negativity constraint. Accuracy of voxel gray scale values estimated by ART is improved by determining weights based on the intersection volume between a pyramidal ray and cubic voxel. The input data to the reconstruction is segmented, and corrected for spatial image distortion. The source and detector positions are also assumed to be known. The size of the reconstruction volume (512... |
