When most people hear the term ultrasound, they think of the well-known technique used to produce pictures of babies as they develop and grow inside the womb.

    Yet ultrasound — the use of sound waves to look inside the body — is used for a variety of other medical reasons. Specifically, a technique called endoscopic ultrasound is increasingly being used to diagnose and treat gastrointestinal and lung diseases, including cancer.

    Endoscopic ultrasound enables doctors to see and evaluate structures outside and within the lining and walls of the upper and lower gastrointestinal tract along with nearby organs, such as the pancreas, liver and gallbladder.

    The highly technical procedure involves passing a thin, flexible tube (endoscope) through a patient’s mouth or rectum and into the upper or lower gastrointestinal tract. The tube is equipped with an ultrasound transducer that produces sound waves to create a viewable image of surrounding tissue.

    Physicians use endoscopic ultrasound to help determine the cause of abdominal pain and :

    • To evaluate and stage various cancers, including esophageal cancer, gastric cancer, lung cancer, pancreatic cancer, bile duct cancer, and rectal cancer. Endoscopic ultrasound can accurately determine the location and severity of a tumor in the gastrointestinal tract or surrounding organs. The technique also enables physicians to examine the size, shape and appearance of adjacent lymph nodes, helping determine whether cancer has spread. This is especially useful in patients with lung cancer.

    • To evaluate acute and chronic pancreatitis and other disorders of the pancreas.

    • To detect gallstones that have migrated into the common bile duct, a tube leading from the gallbladder to the intestine.

    • To study the muscles of the lower rectum and anal canal to determine reasons for fecal incontinence.

    • To assess and biopsy masses in the submucosal lining of the gastrointestinal tract.

    • To assess enlarged stomach folds that may be involved with cancer deep in the stomach wall and unreachable by superficial biopsies.

    • To evaluate Barrett’s esophagus with high-grade dysplasia, an advanced form of the condition, which is caused when the esophagus is repeatedly exposed to stomach acid.

    • To examine neuroendocrine tumors of the gastrointestinal tract or pancreas.

    • To stage MALT lymphoma, a rare form of non-Hodgkin lymphoma usually involving the stomach.

    • To evaluate pancreatic cysts and drain fluid for analysis.

    • To safely and accurately collect fluid samples from the lungs or the abdominal cavity for analysis.

    Endoscopic ultrasound also enables physicians to perform fine- needle aspiration (biopsy) of any suspicious lesions in the esophagus, stomach, rectum or other adjacent organs including the liver and pancreas. as well as lymph nodes to test for cancer.

    Moreover, endoscopic ultrasound enables physicians to inject medicines in affected areas. For instance, patients with pancreatic cancer often experience pain associated with the celiac plexus — a bundle of nerves in the abdomen. With endoscopic ultrasound, physicians can inject a pain medication into the nerve, providing relief for patients with pancreatic cancer.

    Additionally, physicians are beginning to use endoscopic ultrasound to inject chemotherapy directly into a tumor, reducing a patient’s overall exposure to the treatment and helping them avoid the side effects commonly associated with chemotherapy. Research on the effectiveness of this technique is ongoing.

    Because of the highly technical nature of endoscopic ultrasound, the procedure should only be performed by a specially trained endoscopist. Patients who are candidates for endoscopic ultrasound are generally referred to a specialist by their physician or another endoscopist. Preparation involves fasting after midnight prior to the procedure. Patients are sedated for the procedure, which generally takes between 30 and 60 minutes.

    The procedure is minimally invasive and patients are typically allowed to return home on the same day. Some patients may experience a sore throat after the endoscopy, but any discomfort is generally mild. The risks associated with endoscopic ultrasound are low.

    Endoscopic ultrasound is such a specialized procedure that it has only been available at certain healthcare facilities. Now it is available locally through University Medical Center at Princeton’s Endoscopy Suite, which is located on the third floor of the hospital at 253 Witherspoon St., Princeton.

    To find a gastroenterologist or other physician with Princeton HealthCare System. call 888-742-7496 or visit www.princetonhcs.org.

Dr. Eric H. Shen is a board-certified gastroenterologist and a member of the medical staff at Princeton HealthCare System.

Insight into drugs

    Dr. Dorothy Windhorst, dermatologist, researcher and medical information technologist, will discuss “Drug Development from the Medical Perspective,” an exploration of the process by which chemicals are made into drugs under the oversight of the Federal Drug Administration, on Tuesday, Jan. 20, from 10 to 11:30 a.m. at Princeton Windrows independent lifestyle community, 2000 Windrows Drive, Plainsboro.

    The event is free and open to the public. Coffee, tea and pastries will be served. Tours of the community will be available.

    To attend the event, RSVP to Patti Jo Robinson at Princeton Windrows at 800-708-7007 or probinson@princetonwindrows.com.