Gastrointestinal series allow to depict lumen caliber, gross mucosal alterations and wide fistulous tract, but were poorly diagnostic for submucosal or extraluminal features.
CT scan instead provides cross sectional and multiplanar images of intraluminal and extra-mucosal, extra-luminal or even extra-enteric features, but costing higher radiation dose.
It is a safe, multi-planar imaging modality with high soft tissue contrast resolution that does not expose to ionizing radiation, so it is feasible for young patients or when several follow up are required.
Cathartic preparation should be performed in order to clean residual stool from bowel loops from to allow a better visualization of mucosal features and an easier luminal distention as well.
Use of enteric contrast media is recommended, aiming to distend small bowel loops, and it is administered orally at regular intervals approximately 40 minutes before the study.