Ultrasonography

Ultrasound devices can be attached to the end of some endoscopes. This allows doctors to look at the layers of the esophagus (swallowing tube), bronchus (main breathing tube), and parts of the large intestine (bowel). Nearby lymph nodes can be seen, too. Using the ultrasound pictures to guide it, a needle can be placed through the endoscope and cells can be collected from lymph nodes that do not look normal.