CPT® Code 45391

Colonoscopy, flexible; with endoscopic ultrasound examination limited to the rectum, sigmoid, descending, transverse, or ascending colon and cecum, and adjacent structures

A flexible colonoscopy with endoscopic ultrasound examination is a diagnostic procedure that combines two techniques to assess the colon and adjacent structures. During this procedure, a flexible colonoscope, which is a long, thin tube equipped with a camera and light, is inserted into the rectum and advanced through the colon to the cecum or the terminal ileum. The use of air insufflation is crucial as it helps to separate the mucosal folds, allowing for enhanced visualization of the colon's interior surface. As the colonoscope is withdrawn, the physician examines the entire circumference of the colon for any signs of disease, injury, or abnormalities.

Following the colonoscopy, an echoendoscope is introduced into the rectum to perform an ultrasound examination. This specialized endoscope is designed to provide high-resolution images of the rectum, colon, cecum, and surrounding structures. To improve the quality of the ultrasound images, the balloon covering the transducer housing is filled with water, which facilitates acoustic coupling. Continuous ultrasound imaging is conducted, enabling the physician to visualize any lesions, masses, or areas of compression, as well as the walls of the colon and pericolonic structures, such as lymph nodes.

In cases where further investigation is warranted, such as in the presence of a mass or lesion, the echoendoscope can be advanced under direct visualization to the area of concern. This allows for the identification of masses that may be located outside the colon or within its muscular wall. Ultrasound images are captured to assist in locating lymph nodes and other lesions that may be suitable for biopsy. A fine needle aspiration or biopsy catheter is then advanced through the echoendoscope's biopsy channel to obtain tissue samples from the identified areas. The procedure may involve multiple passes at each biopsy site to ensure adequate specimen collection, which is subsequently sent to the laboratory for cytologic examination.