What is EUS?
Endoscopic ultrasound (EUS) uses an endoscope with a tiny ultrasound probe at its tip. Passed through the mouth (or, for the rectum, from below), it sits right next to the organ being examined — so it can see small things that an ordinary ultrasound through the skin, and sometimes even CT or MRI, cannot.
Through the same endoscope a fine needle can be passed to take a sample — called EUS-guided FNA or FNB (fine-needle aspiration or biopsy). This is often the safest way to get a biopsy from the pancreas or from glands deep in the chest and abdomen, without a cut and without a needle through the skin.
When is EUS used?
- A lump or cyst in the pancreas seen on CT or MRI — to look at it closely and, if needed, take a sample
- Suspected small stones in the bile duct when blood tests or scans are unclear — EUS can show whether ERCP is actually needed, sparing many patients an unnecessary ERCP
- Pancreatitis without a clear cause — to look for tiny stones, sludge or a small growth
- A swelling under the lining of the food pipe, stomach or intestine (a "subepithelial lesion")
- Staging of cancers of the food pipe, stomach, pancreas and rectum — how deep the growth goes and whether nearby glands are involved, which guides surgery and treatment
- Enlarged lymph nodes in the chest or abdomen that need a biopsy
- Assessment of chronic pancreatitis
EUS, CT or MRI — which test?
These tests work together; EUS does not replace a CT or MRI.
| Test | Best at | Limits |
|---|---|---|
| CT scan | A wide view of the abdomen and chest; showing whether a disease has spread to other organs | Can miss very small lesions; radiation; no tissue sample |
| MRI / MRCP | Detailed pictures of the bile and pancreatic ducts and of cysts, without any instrument | Can miss very small duct stones; no tissue sample |
| EUS | Very small lesions close to the gut; sampling tissue or cyst fluid | Needs sedation; sees only the area close to the gut wall |
Please bring all earlier scans (CDs and reports) — EUS is planned around them.
Preparing for EUS
- Share your CT/MRI reports in advance — on WhatsApp if you live outside Guwahati — so the right procedure can be planned.
- Fasting: nothing to eat for at least 6 hours before. For a rectal EUS, an enema or bowel preparation is given.
- Blood thinners: tell us if you take aspirin, clopidogrel, warfarin, apixaban, rivaroxaban or similar. If a biopsy is likely, some may need to be paused. Never stop a blood thinner on your own.
- Blood tests such as blood counts and a clotting test may be needed if a biopsy is planned.
- Come with a family member. You must not drive for the rest of the day after sedation.
On the day and afterwards
- You receive sedation and lie on your left side. EUS usually takes 20–45 minutes, a little longer with a biopsy.
- If a pancreatic cyst is sampled, antibiotics may be given to prevent infection.
- You are observed for a few hours. Most people go home the same day.
- A mild sore throat or bloating is common and settles quickly.
- Biopsy results usually take a few working days; some samples need extra tests that take longer.
About biopsy results: EUS biopsy gives a clear answer in most patients, but not every time. Sometimes the sample is not enough to be certain, and a repeat EUS or another test is advised. A "no cancer seen" result is always read together with the scans and your symptoms.
Get medical help urgently if after EUS you have:
- Severe or worsening tummy or chest pain
- Fever or shivering
- Black stools, or vomiting blood
- Repeated vomiting or breathlessness
Call us, or go straight to the nearest emergency department.
Discuss your reports before you travel
Send your scans and blood reports on WhatsApp. If EUS is advised, the consultation, tests and procedure at Hayat Hospital can usually be planned in one trip.
Risks of EUS
A diagnostic EUS (scan only) carries a risk similar to a routine upper endoscopy. When a needle sample is taken, the risk is slightly higher.
| Complication | How often (published studies) | Notes |
|---|---|---|
| Any complication after needle biopsy | About 1 in 100 | Most are minor and settle without surgery |
| Pancreatitis | Less than 1 in 100 after a pancreas biopsy | Usually mild |
| Bleeding | Uncommon | Usually small and stops on its own |
| Infection | Uncommon; mainly after cyst sampling | Antibiotics are given when a cyst is sampled |
| Perforation (a tear) | Rare | Slightly more likely where the gut is narrowed or angulated |
The risk for you depends on what needs to be sampled and your general health, and will be discussed before consent.
Common questions
How is EUS different from a normal endoscopy?
Is EUS painful?
I already had a CT scan. Why do I need EUS?
Can a needle biopsy of the pancreas spread cancer?
Can I go home the same day?
How soon will I get the biopsy report?
Related
Written and medically reviewed by Dr. Mayank Agarwal, MBBS, MD (Medicine), DM (Gastroenterology) · Assam Medical Council Reg. No. 19633 · Last reviewed:
This page gives general information to help you understand the procedure. It does not replace a consultation — whether EUS is right for you depends on your own reports and health.
Based on:
- Elta GH, et al. ACG Clinical Guideline: Diagnosis and management of pancreatic cysts. Am J Gastroenterol 2018;113:464–479.
- Buxbaum JL, et al. ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis. Gastrointest Endosc 2019;89:1075–1105.
- ASGE Standards of Practice Committee (Forbes N, et al.). Adverse events associated with EUS and EUS-guided procedures. Gastrointest Endosc 2022;95:16–26.
- Facciorusso A, Arvanitakis M, et al. ESGE guideline update on endoscopic ultrasound-guided tissue sampling. Endoscopy 2025;57:390–418 (doi:10.1055/a-2524-2596).
- ASGE Standards of Practice Committee (Acosta RD, et al.). The management of antithrombotic agents for patients undergoing GI endoscopy. Gastrointest Endosc 2016;83:3–16.