Abdominal and Pelvic Ultrasound: How to Prepare and What It Can Show

Ultrasound is one of the safest and most widely used scans, with no radiation and no needles. Good preparation, like fasting or a full bladder, makes a big difference to how clear the pictures are.

Imagine being booked for an abdominal ultrasound to look at your gallbladder. You are told not to eat for six hours, and you wonder why. You arrive after a light breakfast, and the gallbladder cannot be seen properly. You have to come back another day.

How ultrasound works

Ultrasound uses high-frequency sound waves that bounce off organs and tissues to create live images on a screen. A small hand-held probe is moved over the skin with gel. It is safe, painless for most people, and can be repeated as often as needed.

What an abdominal ultrasound looks at

• Liver, including fatty liver and lumps
• Gallbladder and bile ducts, including gallstones
• Pancreas (sometimes partly hidden by gas)
• Kidneys, including stones, cysts and swelling
• Spleen
• Aorta, including screening for an aortic aneurysm
• Fluid in the abdomen

What a pelvic ultrasound looks at

• Bladder
• Womb (uterus), including fibroids and the lining
• Ovaries, including cysts
• Prostate, in some cases
• Early pregnancy

Preparation: fasting

For scans of the liver, gallbladder, pancreas and upper abdomen, you are usually asked not to eat for about six hours beforehand. Fasting keeps the gallbladder full so it can be seen clearly and reduces gas in the bowel, which can block the view. You can usually drink water. If you have diabetes, ask how to manage your medicines while fasting.

Preparation: a full bladder

For pelvic and kidney scans, you may be asked to drink about a litre of water an hour before the scan and not empty your bladder. A full bladder lifts the bowel out of the way and acts as a window to see the pelvic organs.,It can be uncomfortable, but it makes a big difference to image quality. If you are struggling, tell the staff; they may let you partly empty your bladder.

Transvaginal scans

For a clearer view of the womb and ovaries, a transvaginal scan may be offered. A slim probe, covered with a protective sheath and gel, is gently inserted a short way into the vagina. It is usually no more uncomfortable than a cervical screening test. You can ask for a chaperone, and you have the right to decline or stop at any time. You usually need to empty your bladder first.

What happens during the scan

You lie on a couch, and gel is applied to your skin. The sonographer moves the probe over your tummy, pressing gently, and may ask you to take a deep breath and hold it, or turn onto your side. The scan usually takes 15 to 30 minutes.,If a particular area is tender, the sonographer may ask about it, as this can help with the diagnosis. Tell them if the pressure is too uncomfortable.

What ultrasound cannot show well

Ultrasound does not see well through gas or bone, so parts of the bowel, pancreas and areas behind gas-filled loops may be hidden. Image quality can also be reduced in people with more abdominal fat. If the scan is inconclusive, you may be offered a CT or MRI scan.

Aortic aneurysm screening

In some countries, men are invited for a one-off ultrasound around age 65 to check for an abdominal aortic aneurysm, a swelling of the main blood vessel in the abdomen. Aneurysms usually cause no symptoms but can be life-threatening if they burst. The scan takes about 10 minutes and finding an aneurysm early allows monitoring or treatment.

Getting your results

The sonographer may not be able to tell you results on the day, as the images are often reviewed and reported by a radiologist or reporting sonographer. Results are usually sent to the healthcare provider who requested the scan within a few days to two weeks. Urgent findings are reported more quickly.

Frequently asked questions

Is ultrasound safe in pregnancy?

Yes. It is the main scan used in pregnancy.

Can I take my medicines while fasting?

Usually yes, with a small sip of water. Check if you have diabetes.

Can I bring someone with me?

Usually yes. Ask the department if children are allowed.

But what if they see something unexpected?

Ultrasound sometimes finds harmless incidental findings, such as simple kidney or liver cysts. Your healthcare provider will explain whether anything needs follow-up.

Related: Gallstones · Fatty liver disease

Sources: Royal College of Radiologists, Society and College of Radiographers, Radiological Society of North America (RadiologyInfo), NHS abdominal aortic aneurysm screening programme.