gastrointestinal disorders
X Ray and Other Imaging Contrast Studies of the Gastrointestinal Tract
CT Scanning of the Abdomen
CT scanning using oral and IV contrast allows excellent visualization of both the small bowel and colon as well as of other intra-abdominal structures. CT colonography (virtual colonoscopy) generates 3D and 2D images of the colon by using multidetector CT and a combination of oral contrast and gas distention of the colon. Viewing the high-resolution 3D images somewhat simulates the appearance of optical endoscopy, hence the name. Optimal CT colonography technique requires careful cleansing and distention of the colon. Residual stool causes problems similar to those encountered with barium enema because it simulates polyps or masses. Three-dimensional endoluminal images are useful to confirm the presence of a lesion and to improve diagnostic confidence. before imaging. For certain indications (eg, obscure Overview of Gastrointestinal Bleeding , CT enterography and CT colonography have largely supplanted standard small-bowel series, enteroclysis, and barium enema examinations. Magnetic resonance (MR) enterography can also be used in a similar fashion to CT enterography. It is typically reserved for younger patients, especially those with inflammatory bowel disease, to reduce lifetime radiation exposure risk. MR enterography is more expensive than CT enterography. 