Comparing CT with endoanal ultrasound (US) and surgical findings, only 24% of perianal fistulae were correctly classified on CT, as compared with 82% by endoanal US in a small series of 25 patients reported by Schratter-Sehn et al [12]. Fluoroscopy Contrast Enema Fluoroscopic contrast enema is not useful in this clinical scenario because it cannot assess the presence or absence of an abscess or fistula tract. There is no relevant literature regarding the use of contrast enema in the evaluation of perianal disease. Fluoroscopy Fistulography Fluoroscopic fistulography is performed by cannulating the external opening of a fistula with a small-gauge catheter, such as an IV catheter, pediatric feeding tube, or lacrimal cannula. Scout radiographs are obtained prior to careful injection of water-soluble contrast material into the fistula tract while obtaining spot radiographs [13]. Care Anorectal Disease should be taken not to inadvertently obscure a distal fistula with the enema or catheter tip or the balloon of a catheter. Fistulography may also be performed with CT by injecting a dilute water-soluble contrast material into an external opening of a fistula; however, there is limited published experience with this technique [14,15]. Fluoroscopic fistulography is rarely performed for perianal disease and has been replaced by modern cross-sectional imaging in this setting. Data on the accuracy of fluoroscopic fistulography are available from small series reported in older medical literature. Weisman et al [13] reported the highest sensitivity (89%) for identification of the primary tract in a retrospective review of 27 patients. In contrast, Kuijpers and Schulpen [16] found fistulography was accurate in only 16% of patients in a retrospective review of 25 patients [16]. The limitations of fistulography include lack of filling of the entire tract or extensions of the tract because inflammatory debris in the tract may prevent contrast filling. In these cases, the internal opening may not be defined.
Anorectal Disease. Comparing CT with endoanal ultrasound (US) and surgical findings, only 24% of perianal fistulae were correctly classified on CT, as compared with 82% by endoanal US in a small series of 25 patients reported by Schratter-Sehn et al [12]. Fluoroscopy Contrast Enema Fluoroscopic contrast enema is not useful in this clinical scenario because it cannot assess the presence or absence of an abscess or fistula tract. There is no relevant literature regarding the use of contrast enema in the evaluation of perianal disease. Fluoroscopy Fistulography Fluoroscopic fistulography is performed by cannulating the external opening of a fistula with a small-gauge catheter, such as an IV catheter, pediatric feeding tube, or lacrimal cannula. Scout radiographs are obtained prior to careful injection of water-soluble contrast material into the fistula tract while obtaining spot radiographs [13]. Care Anorectal Disease should be taken not to inadvertently obscure a distal fistula with the enema or catheter tip or the balloon of a catheter. Fistulography may also be performed with CT by injecting a dilute water-soluble contrast material into an external opening of a fistula; however, there is limited published experience with this technique [14,15]. Fluoroscopic fistulography is rarely performed for perianal disease and has been replaced by modern cross-sectional imaging in this setting. Data on the accuracy of fluoroscopic fistulography are available from small series reported in older medical literature. Weisman et al [13] reported the highest sensitivity (89%) for identification of the primary tract in a retrospective review of 27 patients. In contrast, Kuijpers and Schulpen [16] found fistulography was accurate in only 16% of patients in a retrospective review of 25 patients [16]. The limitations of fistulography include lack of filling of the entire tract or extensions of the tract because inflammatory debris in the tract may prevent contrast filling. In these cases, the internal opening may not be defined.