Radial-scanning flexible EUS of the anorectum and pelvis.

Standard upper gastrointestinal flexible radial EUS probes are well suited for imaging of anorectum and pelvic pathologies. They offer multiple advantages over conventional rigid rectal probes. The current transducers allow imaging at variable frequencies and are Doppler capable. The flexible shaft of the endoscope and optics allow easy probe insertion to upper sigmoid. Flexible radial EUS probes allow evaluation of anal sphincter complex, rectosigmoid mural pathologies, and paraluminal pelvic disorders. A thorough understanding of pelvic anatomy and image orientation is the key to appropriate image interpretation. In this review, we describe the principles and methodology for anorectal EUS imaging using a flexible radial EUS probe.