Genitourinary - CT Protocols - CTisus.com CT Scanning

Genitourinary ❯ Colovesical Fistulae Bladder

Problem	Rule out a fistulae between the bladder and the colon (colovesical fistulae)
Protocol	The key is to use either rectal contrast (30cc iodixanol-350 in 500 cc of saline) or drip contrast in the bladder (30cc iodixanol-350 in 500 cc of saline) under gravity. Although either technique works the rectal contrast is usually more successful. We scan from the level above the crests till beneath the bladder. We obtain non contrast scans, scans with rectal or bladder contrast administered and scans after drainage of the colon or bladder. Images are reviewed with axial, coronal and select sagittal views.
Pearls	The most common cause for a colovesical fistulae is diverticulitis with crohns disease being a distant second. The causes of diverticulitis usually are a result of repeated instances of diverticulitis Other causes of colovesical fistulae include colon cancer, trauma and as a complication of instrumentation We are always careful to look at the bladder colon interface as when there is a loss of plane and extensive diverticular disease it may represent the prodromal state before the actual fistulae develops. Early intervention can prevent long term complications. Causes of fistulae include perforation trauma including GSW as well as forcefull placement of a foley catheter and as a complication of biopsy at cystoscopy The key to detecting the colovesical fistulae is adequate distension of the bladder and/or colon. Our experience is that rectal contrast works better and is more likely to show the track and be useful for surgical planning. The reason we obtain non contrast scans is to exclude a foreign body (rare) but to make sure there is no high density matter that could confuse us later in the study. Patient cooperation as always is critical to the study.