Traditionally, fistulography has been the most rapid and widely used technique in the evaluation of communication between the skin opening and bowel or abdominal cavity (Fig. 27.2). During fistulography, the external skin opening is cannulated, followed by injection of a water-soluble contrast agent under fluoroscopic guidance to delineate the fistulous tract. Multiple fluoroscopic images are usually obtained in various obliquities by moving the patient in different positions to allow for dependent drainage and improved visualization. Using this thorough technique the location of the fistula, length of the tract and extent of the bowel wall disruption can be adequately evaluated. Water-soluble agents such as Gastrografin have the advantage of rapid absorption within the peritoneal cavity while causing minimal inflammation. However, Gastrografin usually provides less mucosal detail compared to barium. Therefore, a water-soluble iodinated contrast agent is often injected initially, followed by barium if no extravasation is seen and additional detail is required. While a cost-effective and efficient diagnostic test, a fistulogram may still fail to provide detailed information regarding contained abscess collections, exact location of the fistula in the GI tract, or additional bowel pathology proximal or distal to the fistula. Fistulography is also contraindicated in patients with sepsis, as the technique may result in bacteremia. If the result of fistulogram is inconclusive, additional imaging studies such as a small bowel follow-through, CT, or MRI can be performed.