For patients with fistulas, especially those with high-grade complex fistulas, understanding the direction of the fistula and finding the internal orifice are key to the success of the surgery. Therefore, MRI of fistula patients, especially those with high-grade complex fistulas, can help the surgeon to understand the fistula’s alignment and find the location of the internal orifice as much as possible, which can improve the diagnosis and healing level of the surgery. If you know exactly where the internal opening is and the course of the fistula is clear, you have a higher chance of a one-time surgical cure and an understanding of the anatomy. Therefore, it is recommended that patients with anal fistulas, especially those with high-grade complex fistulas, have MRI, which can be very helpful before surgery.