Contrast-enhanced endoanal and transperineal sonography in perianal fistulas.

Background/aims: To improve the diagnostic potential of ultrasound in patients with perianal fistulas, by performing a combined perineal and endorectal Doppler sonography investigation before and after contrast enhancement with hydrogen peroxide.

Methodology: Ten patients (9 male and 1 female) with perianal fistulas were tested. After contrast-free transperineal and endoanal sonography, hydrogen peroxide was injected in the fistulas and the ultrasound examinations were repeated.