Using an Endoscopic Ultrasound (EUS), it is possible to detect lesions in the inner part of the digestive system wall and even in the organs outside it. The device has a dual-function - it's an endoscope (providing a picture of the space in the digestive system) and it's also an ultrasound transducer, which gives an ultrasonographic picture of events occuring across the wall of the digestive system.
During the procedure, similar to that of a standard endoscopy, the endoscopy provides imaging of the entire wall and its layers. It also allows observation of adjacent structures such as the pancreas, bile ducts, gallbladder, spleen, liver, lymph nodes and local blood vessels.
Due to the location of the ultrasound transducer within the digestive system and its proximity to the internal organs, the ultrasound is in high-resolution.
If a lesion is detected both in proximity to and with the use of ultrasound guidance, the lesion can be removed using a delicate needle passed through the endoscope. With this method, a cellular or fluid sample is taken for microscopic or chemical analysis. This information allows for a more accurate diagnosis.
Using this test, tumor processes, their status (benign or malignant), location in the digestive system wall (esophagus, stomach, duodenum, or rectum), and how much they've spread is indentified. It allows diagnosis, characterization and sampling of cystic processes, inflammatory processes or tumors in the pancreas, the identification of tumors or gall stones, description and sampling of regional lymph nodes.
Beyond the diagnostic contribution of the device, the endoscopic ultrasound can also be a means of treatment, for example:
- In cases of severe pain from pancreatic tumor or chronic inflammation where a reduction in the level of pain can be achieved by direct injection of the anesthetic into the nerve root that sends out the pain sensation.
- Another example for treatment using EUS is in the draining of a pancreatic cyst or abscess by inserting a needle or an internal drain into the lesion, guided by ultrasound direction.
It seems likely that other uses of this imaging method will be developed or found in the near future.