Diagnosis of vesico-intestinal fistulas by contrast medium enhanced 3-D ultrasound

Standard diagnostic tools for vesico-intestinal fistulas are cystoscopy, cystography, colonoscopy, and contrast enema. The aim of our study was to evaluate the efficacy of transrectal 3D-ultrasound with contrast media in these patients. From 5/98 to 12/99 we examined 10 patients with symptoms of a vesico-intestinal fistula (pneumaturia, faecaluria). After placement of a transurethral catheter a transabdominal ultrasound examination (Kretz Combison 530) was performed with the bladder half full to evaluate the bladder wall. Then the bladder was filled with diluted ultrasound contrast media (Levovist 40 mg/ml) to visualize the flow from the bladder towards the fistula. To verify a flow through the bladder wall a colour Doppler sonography of the region of interest was added. To evaluate form and extent of the fistula a transrectal ultrasound with 3D-image assessment was performed. Using this technique it was possible to demonstrate a vesico-intestinal fistula in 9 of 10 patients. In all cases these findings were confirmed by the standard diagnostic procedures. The fistulas were caused by: bladder carcinoma (n = 1), carcinoma of the colon (n = 2), Crohn's disease (n = 3) and diverticulitis of the sigma (n = 3). One patient presented with a neovesico-intestinal fistula in an irradiated local recurrence of bladder carcinoma. In one patient with Crohn's disease whose only symptom was pneumaturia all diagnostic tools failed to provide the diagnosis. For the first time vesico-intestinal fistulas could be demonstrated by ultrasound with 3D-image assessment using contrast media. This technique might be an effective addition to the standard diagnostics of vesico-intestinal fistulas reducing the exposure to radiation.