Endoscopic Ultrasound and Guided Fine Needle Aspiration Biopsy

Endoscopic ultrasound (EUS) is a medical procedure in endoscopy combined with ultrasound to obtain images of the internal organs in the chest and abdomen. It can be used to visualize the walls of these organs, or to look at adjacent structures. Combined with Doppler imaging, nearby blood vessels can also be evaluated. Minute lesions down to a size of 5mm may be imaged and consequently biopsied. Organs such as the liver, pancreas and adrenal glands are easily biopsied as are any abnormal lymph nodes. There is a low rate of complications with this procedure (below 1-2%) and it is performed on a routine basis.

The procedure is performed by gastroenterologists who have had extensive advanced training and used mainly in the upper digestive tract but can be used in the colorectal area too. The procedure feels almost identical to the Esophagogastroduodenoscopy or EGD unless an ultrasound-guided biopsy (Fine Needle Aspiration or FNA) of deeper structures is performed. The procedure normally takes from 20 minutes to 2 hours (for an FNA) depending on the difficulty of obtaining accurate specimens.

For a EUS of the upper digestive tract, a probe is inserted through the scope into the esophagus, stomach and duodenum during an EGD. It allows for screening of pancreatic cancer, esophageal cancer, and gastric cancer as well as benign tumors of the upper gastrointestinal tract. It also allows for characterization and biopsy of tumors/lesions found in the tract. This is done by inserting a needle (down the scope) through the stomach lining into the target and is called Endoscopic-Guided Fine Needle Aspiration (FNA). A Laboratory Technician is present at the procedure to prepare the biopsy slides and a Pathologist is then called in to let the Endoscopist know whether or not he/she is obtaining accurate specimens or to give a diagnosis. All specimens are taken to the lab for further examination but on occasion a diagnosis may be obtained at the close of the procedure.

The technique is highly sensitive for detection of Pancreatic Cancer (90-95% sensitivity). EUS with FNA is very useful in establishing an initial tissue diagnosis of malignancy and also accurately staging patients reducing the need for surgery and the risks thereof.