To perform an endoscopic ultrasound, your doctor passes a thin, flexible tube (endoscope) through your mouth or anus. A small ultrasound device (transducer) within the tube produces sound waves that create a precise image of surrounding tissue.
Doctors at Mayo Clinic use two types of transducers. One, a radial imaging device, produces a 360-degree, cross-sectional image (also called a "slice"). The other device, a curved linear array, can guide a biopsy (fine-needle aspiration) of your lymph nodes and any tumors.
Another kind of ultrasound allows very high-resolution imaging of the surface of your digestive tract. Doctors use this image to help determine the size and depth of small tumors (nodules) within the wall of your digestive tract.
When combined with fine-needle aspiration, endoscopic ultrasound is a minimally invasive alternative to exploratory surgery for removing tissue samples. Doctors also use endoscopic ultrasound to guide drainage of pseudocysts, injections and pain-relieving treatments.
Your doctor may use endoscopic ultrasound for:
- Abdominal mass assessment and cancer staging. Endoscopic ultrasound can accurately determine how deeply a tumor penetrates your gut wall in esophageal, gastric, rectal, pancreatic and lung cancers. Examining the size, shape and ultrasound appearance of adjacent lymph nodes also helps your doctor determine whether cancer has spread.
- Bile duct stone detection. Doctors traditionally detected stones in the bile tubes leading from your gallbladder to your intestine using an endoscopic retrograde cholangiogram (ERCP). Endoscopic ultrasound is less invasive than is ERCP and can detect these stones with equal accuracy.
- Disease diagnosis. Endoscopic ultrasound can help your doctor diagnose diseases of the internal organs such as chronic pancreatitis or pancreatic cysts.
- Fluid collection. Endoscopic ultrasound allows your doctor to safely and accurately collect fluid samples from your lungs or abdominal cavity for analysis.
Conditions diagnosed with endoscopic ultrasound
Your doctor may use endoscopic ultrasound to determine the cause of symptoms such as abdominal pain, to evaluate a growth (tumor), or to diagnose and stage diseases of your digestive tract and lungs, including: