Endoscopic ultrasound. As an alternative to MRI that makes very similar photos, an endoscopic ultrasound goes within your anus with a small lighted camera in addition to a little ultrasound probe. However, much more serious fistulas that drain could lead to infection within the bordering pores and skin and organs. https://sarthicare.com/best-fissure-treatment-in-bangalore-for-long-lasting-pain-relief/