Please tell me if an abdominal ct is the same as a virtual colonoscopy?

Not the same: An abdominal CT scan will visualize the pattern of the colon and bowel as it is situated in the peritoneal cavity. It does not visualize the content of the colon unless the lesion is so large that it distorts the shape of the bowel. Virtually colonoscopy allows visualization of the interior content of the bowel without actually employing a scope.