Objectives: Nonhazardous enteral administration of indocyanine green solution was performed to detect enterovesical occult microfistulas in patients with Crohn's disease before the fistulas had become readily apparent.
Methods: A total of 12 patients with Crohn's disease who were suspected from their clinical manifestations of having enterovesical fistulas underwent study. For detection of the fistulas after oral or rectal administration of the indocyanine green solution, urine was collected and examined using a colorimeter to check for contamination with indocyanine green. The effectiveness of the indocyanine green test and conventional x-ray study was compared.
Results: The indocyanine green test was positive after either oral or rectal administration in 11 of the 12 patients, providing a rate of accurate diagnosis of 92 percent (11/12 patients). In contrast, the rate of accurate diagnosis using the x-ray study was only 17 percent (2/12 patients). Furthermore, in eight patients with occult fistulas, accurate diagnosis could be made in none using the x-ray study, whereas all showed positive results with use of the indocyanine green test.
Conclusions: The ability to diagnose obscure fistulas using the indocyanine green test was 92 percent. This indocyanine green test was highly diagnostic, whereas conventional examinations are often complicated and much less diagnostic.