Current applications of transperineal ultrasound in gastroenterology

Abstract

Transperineal ultrasound is an inexpensive, safe and painless technique that dynamically and non-invasively evaluates the anorectal area. It has multiple indications, mainly in urology, gynaecology, surgery and gastroenterology, with increased use in the last decade. It is performed with conventional probes, positioned directly above the anus, and may capture images of the anal canal, rectum, puborectalis muscle (posterior compartment), vagina, uterus, (central compartment), urethra and urinary bladder (anterior compartment). Evacuatory disorders and pelvic floor dysfunction, like rectoceles, enteroceles, rectoanal intussusception, pelvic floor dyssynergy can be diagnosed using this technique. It makes a dynamic evaluation of the interaction between pelvic viscera and pelvic floor musculature, with images obtained at rest, straining and sustained squeezing. This technique is an accurate examination for detecting, classifying and following of perianal inflammatory disease. It can also be used to sonographically guide drainage of deep pelvic abscesses, mainly in patients who cannot undergo conventional drainage. Transperineal ultrasound correctly evaluates sphincters in patients with fecal incontinence, postpartum and also following surgical repair of obstetric tears. There are also some studies referring to its role in anal stenosis, for the measurement of the anal cushions in haemorrhoids and in chronic anal pain.

Keywords: Fecal incontinence; Inflammatory perianal disease; Obstructed defecation; Posterior compartment; Transperineal ultrasound.

Figure 1

Standard transperineal ultrasound images. A: Midsagittal view; B: Upper anal canal in the transversal view; C: Transversal view of the middle anal canal. SP: Symphysis pubis; U: Urethra; B: Bladder; V: Vagina; UT: Uterus; R: Rectum; A: Anal canal; PR: Puborectalis muscle; IAS: Internal anal sphincter; EAS: External anal sphincter.

Figure 2

A woman with symptoms of obstructed defecation. A: Transperineal ultrasound at rest; B: Transperineal ultrasound during maximal straining, after rectum filling with ultrasonographic coupling gel, showing a herniation of the anterior rectal wall into the vagina confirming a retocele (arrow). SP: Symphysis pubis; U: Urethra; B: Bladder; V: Vagina; R: Rectum; A: Anal canal; PR: Puborectalis muscle.

Figure 3

A woman with symptoms of obstructed defecation. A: Transperineal ultrasound at rest, after rectum filling with ultrasonographic coupling gel; B: Transperineal ultrasound during maximal straining, after rectum filling with ultrasonographic coupling gel, showing a herniation of the rectal wall into the anal canal confirming a rectal intussusception (arrow). U: Urethra; B: Bladder; V: Vagina; R: Rectum; A: Anal canal.

Figure 4

Transversal view of the anal canal (A) in a case of inflammatory perianal disease, fistula (left image, between lines) and abscess (right image, arrow).