Investigations

• Computed tomography (CT) is the preferred initial imaging modality, with diagnostic accuracy of 90% to 100%. The preferred protocol involves administering oral and rectal contrast before intravenous contrast to visualize the passage of enteric contrast into the bladder. (1)
• Magnetic resonance imaging (MRI) offers superior soft-tissue resolution, multiplanar imaging capability, and approaches 100% sensitivity and specificity for vesico-colic fistulas. (2)
• Ultrasonography has limited diagnostic value as a primary modality, although some studies report good diagnostic yield. (3)
• Barium enema and small bowel follow-through have largely been replaced by cross-sectional imaging, with a diagnostic accuracy of only approximately 30%. (4)
• Cystography demonstrates contrast extravasation outside the bladder but has similarly low diagnostic accuracy of 20% to 30%. (4)

Reference:

1. Najjar SF, Jamal MK, Savas JF, Miller TA. The spectrum of colovesical fistula and diagnostic paradigm. Am J Surg. 2004 Nov;188(5):617-21
2. Tang YZ et al. Imaging features of colovesical fistulae on MRI. Br J Radiol. 2012 Oct;85(1018):1371-5
3. Sutijono D. Point-of-care sonographic diagnosis of an enterovesical fistula. J Ultrasound Med. 2013 May;32(5):883-5
4. Golabek T et al. Enterovesical fistulae: aetiology, imaging, and management. Gastroenterol Res Pract. 2013;2013:617967.