1. A method for performing virtual examination of an object comprising: performing at least one scan of an object with the object distended by the presence of a contrast agent; performing at least one scan of the object with the object relieved of the contrast agent; converting the scans to corresponding volume datasets comprising a plurality of voxels; performing image segmentation to classify the voxels of each scan into a plurality of categories; registering the volume datasets of each scan to a common coordinate system; displaying at least two of the volume datasets in a substantially simultaneous manner; performing virtual navigation operations in one of the volume datasets and having the corresponding navigation operations take place in at least one other volume dataset; and evaluating the at least one scan with the object distended and the at least one scan with the object relieved to identify regions where contrast is more visible in one of said scans and evaluating the scan with more contrast in a region of interest to determine physiological characteristics of the object, wherein said step of image segmentation includes classifying voxels based on local intensity vectors of the voxels and further includes using a region growing algorithm to identify regions of the object based on the classified voxels.