The endorectal ultrasound is a relatively new diagnostic method, which give us the opprtunity to display the anatomical layers of rectum. The probe is inserted gradually into the ampulla or is mounted on a flexible endoscope. The transducer is located within a water-filled balloon in order to achieve close contact with the walls of the intestine. The transducer, rotating 360 degrees co-axially, supplies cross-sections of the intestinal anatomy (mucosal, submucosal and muscular layer). The principal indication for performing endorectum ultrasound is the staging of neoplasms (rectal cancer).
The method has very good diagnostic sensitivity, regarding the display of tumor invasion, while the imaging ability to evidentiate infiltrated lymph nodes is relatively reduced. In case that during the examination, limited filtration is being demonstrated, minor resection of the tumor could be attempted with transanal endoscopic microsurgery (TEMS). Less commonly, endorectum ultrasound is used to investigate perirectal abscesses or perianal abscesses, which may extend centrally at the level of rectum.