Endoscopic ultrasound

What is an endoscopic ultrasound?

An endoscopic ultrasound (EUS) combines an endoscopy and an ultrasound scan. Your doctor passes a long, flexible tube called an endoscope, which has a tiny camera, light and ultrasound probe on the end, into your body to get detailed pictures of organs that are hard to see clearly from outside, such as your oesophagus, stomach, pancreas, bile ducts and nearby lymph nodes.

Why might I need an EUS?

You might have an EUS to find the cause of your symptoms, to see how big an abnormal area or tumour is and whether it's spread to nearby areas such as lymph nodes, or to take a tissue sample (a biopsy) using a thin needle passed along the endoscope. It can also be used to place a small tube (a stent) to relieve a blockage.

What are the benefits of having one?

An EUS gives a much closer, more detailed view of organs like your pancreas and bile ducts than scans taken from outside your body. It also means a biopsy can often be taken during the same appointment, rather than needing a separate procedure.

Are there different types of EUS?

There are 2 main types, depending on which organs need to be examined:

• an upper EUS, which looks at your oesophagus, stomach and the first part of your small bowel (duodenum), along with nearby organs such as your pancreas, gallbladder and lungs, done by passing the endoscope through your mouth
• a lower EUS, which looks at your colon and rectum, done by passing the endoscope through your anus.

If you're having your throat and lungs examined, this may also be called an endobronchial ultrasound (EBUS).

How do I prepare for an EUS?

You'll be given written instructions on how to prepare, so it's important to read and follow them, and call the number provided if you have any questions. You may have a pre-assessment appointment a few days beforehand to check you're well enough for the test, along with a blood test to check your blood levels and how well your blood clots.

Tell your doctor if you're taking medicine that affects blood clotting, such as aspirin, clopidogrel, warfarin, heparin, apixaban, rivaroxaban or ticagrelor, as you may need to stop these beforehand. You won't be able to eat for 6 hours before the test, though you may be able to drink sips of water up to 2 hours beforehand. Wear loose-fitting, comfortable clothing and leave valuables at home.

What happens during the test?

An EUS usually follows these steps:

• a nurse asks about your medical history and any allergies, and checks things like your blood pressure
• your doctor or specialist nurse explains the procedure and asks you to sign a consent form
• you may be asked to remove dentures or glasses, and a plastic guard is placed in your mouth to protect your teeth
• most people have sedation, which makes you drowsy but able to follow instructions, and a numbing spray is used on the back of your throat, which can taste bitter and make you cough
• you lie on your left side while your doctor passes the endoscope through your mouth, or through your anus for a lower EUS, to the area being examined
• your doctor takes pictures and may take biopsies, which shouldn't be painful, before gently removing the endoscope.

The test itself usually takes 15 to 45 minutes, though you should expect to be at the hospital for several hours in total to allow time to prepare and recover.

What happens after the test?

If you didn't have sedation, you can usually go home shortly afterwards, though you'll need to wait about an hour, until the throat spray wears off, before eating or drinking. If you had sedation, you'll need to stay for an hour or two until you're fully recovered, and you'll need a friend or relative to take you home and stay with you overnight.

For 24 hours after sedation, you shouldn't drive, drink alcohol, operate heavy machinery or sign important documents. You may have some bloating or discomfort for a few hours, or a sore throat for a few days, both of which are common after this kind of test.

What are the risks?

An EUS is generally a safe procedure. Possible risks include:

• a sore throat, which is common and usually settles within a few days
• a small amount of bleeding after a biopsy, which usually stops on its own
• a small risk of infection at the biopsy site
• a small chance of damage to your teeth, which the mouth guard helps prevent
• a reaction to the sedative, affecting your breathing, heart rate or blood pressure, which is more likely in older people or those with heart or lung conditions
• a very small risk of a tear (perforation) in the lining of your oesophagus, stomach or bowel, which may need an operation to repair.

Your team will explain who to contact if you have any problems after you get home.