Fig. 2
From: Dynamic contrast-enhanced MR imaging in identifying active anal fistula after surgery
St James’s University Hospital Classification. a-c 65-year-old male from Group IV, Grade 3 of classification: oblique coronal T2WI fat suppression sequence (a), oblique axial T2WI sequence (b) and oblique axial T1WI enhancement sequence (c) showing the transsphincteric fistula (arrow); (d-f) 54-year-old male from Group IV, Grade 4 of classification: oblique coronal T2WI fat suppression sequence (d) and oblique axial T1WI enhancement sequence (f) showing the transsphincteric fistula (arrow), sagittal T2WI fat suppression sequence (e) showing the main fistula (arrow) and secondary track (arrowhead)