*3.3.8 Preoperative detection of occult enterovesical fistulas in patients with Crohn's disease*

Efficacy of oral or rectal administration of indocyanine green solution. In a study realized by Sou et al. [38] whose objectives were to detect enterovesical occult microfistulas in patients with Crohn's disease before the fistulas had become readily apparent, nonhazardous enteral administration of indocyanine green solution was performed. The methods that were used collected a total of 12 patients with Crohn's disease who were suspected from their clinical manifestations of having enterovesical fistulas. Urine was collected and tested for contamination with indocyanine green by using a colorimeter to detect fistulas following oral or rectal administration of the indocyanine green solution. In addition, the efficacy of the indocyanine green test was compared to that of the "classical" X-ray sample.

The ICG test was positive in 11 of the 12 cases after either oral or rectal administration, resulting in a 92% correct diagnosis rate (11/12 patients).

The percentage of right diagnoses using an X-ray analysis, on the other hand, was just 17% (2/12 patients).

Furthermore, none of the eight patients with secret fistulas could be accurately diagnosed using an X-ray analysis, but all showed promising results when the indocyanine green approach was used.

The researchers concluded that the indocyanine green test had a 92% accuracy rate in diagnosing obscure fistulas and was highly diagnostic, while traditional examinations are often complicated and inaccurate (**Figure 15**).

**Figure 14.** *Colon polyp removal. Endoscope inside colonoscopy for colon polyps.*
