transrectal ultrasound (tranz-REK-tul UL-truh-sownd)
A procedure in which a probe that sends out high-energy sound waves is inserted into the rectum. The sound waves are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissue called a sonogram. Transrectal ultrasound is used to look for abnormalities in the rectum and nearby structures, including the prostate. Also called endorectal ultrasound, ERUS, and TRUS.