Endorectal Ultrasound Scan

1.1 Endoscopic ultrasound anatomy of rectum Assessment of the rectum with endoscopic ultrasound [EUS] has evolved as an excellent tool in the management of malignant as well as benign diseases of the rectum and anus. The endoluminal ultrasound provides accurate evaluation of rectal, perirectal and perianal pathology. Initially, the standard radial endoscopic ultrasound scan was used in the assessment of the rectum as people were familiar with its usage in the management of upper gastrointestinal tract problems. The rigid endoscopic ultrasound scan has been used since the early 80’s. Improvements in the instrument as well as high resolution of the ultrasonic waves have resulted in very significantly improved image quality and accurate interpretation of this particular examination. Color Doppler as well as 3D imaging has also added some benefits to this modality. The EUS has now become an excellent tool in the preoperative staging of low rectal cancer compared to CT scan and/or MRI. The rigid probe is 20cm in length, has the rotating transducer at the tip covered by a balloon filled with water. There are different types of linear as well as radial scanning devices available in the market and the frequencies vary from 3.5 MHz to 15MHz. EUS is portable, cost effective and can be completed in a short time with minimal discomfort to the patient. Most of the patients can have it done without any sedation and the recovery time is very short.