[Pay attention to the imaging diagnosis of complex anal fistula].

The diagnosis and treatment of complex anal fistula has been a significant challenge. Unwise incision and excessive exploration will lead to the secondary branch, sinus and perforation. A simple fistula may become a surgical problem and result in disastrous consequences. Preoperative accurate diagnosis of anal fistula, including in the internal opening, primary track and location of the fistula, extensions and abscess, is important for anal fistula treatment. In the diagnosis of anal fistula, imaging examination, especially MRI plays a crucial role. Localization and demarcation of anal fistula and the relationship with sphincter are important. MRI has been an indispensable confirmatory imaging examination.