Colon & Rectal Surgery

Rectal Cancer

Delta Medix Patient General Information

Endorectal Ultrasound

An ultrasound is a type of imaging study that utilizes sound waves to produce images of internal structures or organs onto a screen. In an Endorectal Ultrasound, a probe with a balloon on the end of it is inserted into the rectum and the balloon is inflated with water. A small transducer is attached to the end of the probe and is actually inside the balloon that is filled with water. The water improves the conduction of sound waves through a fluid medium. High frequency sound waves (ultrasound waves) are generated. The sound waves echoes are then detected by the transducer and are converted by a computer to generate an image called a sonogram that is projected onto a screen. In an Endorectal Ultrasound, an ultrasound of the rectal walls is performed and the walls of the rectal are being converted to images on a screen.

An Endorectal Ultrasound is most often utilized when a patient is diagnosed with a rectal cancer to perform what is called staging. In this process, an ultrasound is done to determine the depth of tumor penetration in the rectal walls as well as any local lymph node enlargement or metastasis that may occur with rectal cancer.

An Endorectal Ultrasound may also be used at times to determine if there is a defect or disruption in the rectal sphincter. A defect in the rectal sphincter is often associated with fecal incontinence but is not always the cause of fecal incontinence.

Endorectal Ultrasound ImageThe procedure itself is often quite painless. A patient is required to lie on his or her side while the study is being performed. There is no sedation or anesthesia required for the procedure, but the patient needs to have an enema about 1-2 hours prior to the procedure to provide a clean rectum in order for the rectal walls to be clear of fecal material in ensure a proper scan.

A normal Endorectal Ultrasound. The layers of the rectum are seen as alternating bands and are comprised of the hyperechoic mucosa (m), hypoechoic muscularis mucosa (mm), hyperechoic submucosa (s), and hypoechoic muscularis propia(mp).