Research Article

3D-EAUS and MRI in the Activity of Anal Fistulas in Crohn’s Disease

Figure 2

Submucosal fistula in the superficial plane corresponding to the level of the distal extremity of anal canal. In (a) 3D-EAUS, including the hyperechoic layer of the submucosal portion of the external anal sphincter (EAS), shows a submucosal fistula extending from 3 o’clock to 5 o’clock, lying external to the submucosal portion of the EAS (yellow arrows). The same plane on MRI (b), which could be avoided in this kind of fistulas (white arrow); 3D-EAUS is often sufficient as a preoperative diagnostic method.
(a)
(b)