An abdominal ultrasound shows the liver, gallbladder, bile ducts, pancreas, spleen, kidneys and the abdominal aorta, and a whole-abdomen scan adds the bladder and pelvic organs. It sees the stomach and bowel poorly because gas blocks sound waves, so those need endoscopy or CT. Most centres ask for a fast of several hours and, for the bladder, a few glasses of water beforehand.
What organs does an abdominal ultrasound show?
An abdominal ultrasound shows the solid organs of the upper abdomen and the large blood vessels behind them. RadiologyInfo lists the kidneys, liver, gallbladder, bile ducts, pancreas, spleen, and the abdominal aorta and other abdominal blood vessels. MedlinePlus lists the liver, gallbladder, pancreas and kidneys plus the inferior vena cava and aorta. In India the request form usually says "USG upper abdomen" for that set, or "USG whole abdomen" when the bladder, uterus and ovaries or prostate are added; RadiologyInfo's paediatric page lists the bladder, uterus, ovaries, testicles and appendix among the structures an abdominal scan can include.
| Organ | What the scan checks | Source |
|---|---|---|
| Liver | Size, fatty change, cirrhosis, tumours, abnormal liver blood tests | MedlinePlus, RadiologyInfo |
| Gallbladder and bile ducts | Gallstones, inflammation (cholecystitis), blocked or widened ducts | NIDDK, MedlinePlus |
| Pancreas | Swelling (pancreatitis), fluid, masses | MedlinePlus |
| Spleen | Enlargement (splenomegaly) | MedlinePlus |
| Kidneys | Stones, swelling from blocked urine (hydronephrosis), infection, size | MedlinePlus, RadiologyInfo |
| Aorta and vena cava | Aneurysm (widening), clots, narrowing on Doppler | RadiologyInfo |
| Bladder (whole-abdomen scan) | Wall, stones, emptying; needs a full bladder | RadiologyInfo, NHS |
| Free fluid | Ascites, abscess, fluid after injury | MedlinePlus |
The scan is live, so the radiologist can watch an organ move and add a Doppler study to show blood flow through a vessel.
What can an abdominal ultrasound not see well?
An abdominal ultrasound sees the stomach and bowel poorly, and it cannot see through bone or deep fat. RadiologyInfo explains why: air or gas blocks sound waves, so ultrasound is not ideal for the air-filled bowel or for organs hidden behind it; it is not useful for the air-filled lungs; it cannot penetrate bone; and in larger patients the extra tissue weakens the sound waves on their way in and back, so the pictures are less clear. That is why a scan that reports "bowel gas obscures the pancreas" is not a faulty scan.
For each blind spot there is a better test:
- Stomach and food pipe: an endoscopy, which the NHS says gives a clearer view of structures such as the stomach when an ultrasound probe is attached to the scope.
- Bowel wall and appendix in adults: a CT scan when ultrasound cannot see past gas.
- Stones hidden in the bile duct: the NIDDK lists MRI and ERCP for stones in the ducts, and a HIDA scan for abnormal gallbladder contraction.
- Small stones in the pancreas or a mass behind gas: CT or endoscopic ultrasound.
Ultrasound can also miss early disease in the organs it does see. The 2022 PLoS One study of North Indian adults notes that ultrasound can miss mild fatty liver, which is why it also used FibroScan. A normal scan with abnormal blood tests is a reason to ask a gastroenterologist which test comes next, not a reason to stop.
What are the common findings on an abdominal ultrasound report?
Fatty liver, gallstones and kidney stones are the three findings that fill most Indian ultrasound reports. A 2022 community study in PLoS One scanned 828 urban Delhi and 832 rural Haryana adults aged 30 to 60 and found fatty liver on ultrasound in 65.7% (urban) and 61.1% (rural); diabetes, central obesity and insulin resistance roughly doubled the odds. The NIDDK says ultrasound is the best imaging test for finding gallstones and can pick up silent stones in people with no symptoms. MedlinePlus lists the abnormal results an abdominal scan can show: abdominal aortic aneurysm, abscess, appendicitis, cholecystitis, gallstones, hydronephrosis, kidney stones, pancreatitis, an enlarged spleen, portal hypertension, liver tumours, bile duct obstruction and cirrhosis.
A few report phrases cause needless worry:
- "Grade 1 fatty liver" is mild fat in the liver. It is common and reversible with weight and sugar control, and it is a reason for blood tests, not panic.
- "Simple renal cortical cyst" is a fluid sac in the kidney; the scan is used precisely because it tells a simple cyst from a solid growth.
- "Aorta normal calibre" means no aneurysm. The NHS screening programme counts an aorta of 3 to 4.4 cm as a small aneurysm, 4.5 to 5.4 cm as medium with scans every 3 months, and 5.5 cm or more as large, which is referred to a vascular surgeon.
RadiologyInfo says a radiologist interprets the images and sends a signed report to the doctor who ordered the scan; in India you usually get the report the same day.
How do I prepare for an abdominal ultrasound?
Fast for the hours the centre tells you, drink water beforehand if the bladder is part of the scan, and carry your earlier reports. RadiologyInfo says you may be asked to avoid food and drink for several hours so that the gallbladder and upper abdominal organs are easier to see; a full gallbladder shows stones clearly, and an empty stomach means less gas in front of the pancreas. Cleveland Clinic says an empty stomach is needed for ultrasounds involving the digestive tract. MedlinePlus says you will likely be asked not to eat or drink for several hours and that your provider gives the exact instructions. Confirm the number of hours when booking, because it varies by centre.
For the bladder the preparation is the reverse. RadiologyInfo says to drink several glasses of water 1 to 2 hours before the scan and not to urinate so the bladder is reasonably full when scanning starts; the NHS says the same for scans that need a full bladder. A whole-abdomen scan therefore needs both: fasting and a full bladder.
- Take regular medicines with a small sip of water unless told otherwise.
- If you have diabetes, ask the centre for the first slot and ask your doctor how to adjust the morning dose.
- Wear loose clothing and leave jewellery at home; RadiologyInfo says you may be given a gown.
- No preparation is needed for an aorta-only screening scan, according to Cleveland Clinic.
What happens during the scan and how long does it take?
You lie on a couch, gel goes on the skin, and a handheld probe is moved over the abdomen for 10 to 30 minutes. MedlinePlus describes the sequence: a clear water-based gel is applied, the transducer sends high-frequency sound waves and picks up the echoes, and you may be asked to change position or hold your breath briefly so the liver and spleen drop below the ribs. MedlinePlus says the test usually takes under 30 minutes; the NHS gives 10 to 45 minutes for ultrasound scans in general; Cleveland Clinic and the NHS both put an aorta-only screening scan at about 10 to 15 minutes.
The scan is safe. RadiologyInfo says standard diagnostic ultrasound has no known harmful effects on humans, and MedlinePlus says there are no known risks and no ionising radiation. The NHS says an external probe is usually not painful but can be uncomfortable over an already tender area, and that you can ask the person scanning to stop at any time. A Doppler study, which RadiologyInfo describes as showing blood movement through arteries and veins, adds a few minutes.
Results are usually ready the same day. The price depends on the city and whether it is an upper-abdomen or whole-abdomen scan; see the ultrasound cost page for current ranges, and note that government hospitals charge far less or nothing under state schemes.
When does an ultrasound need a follow-up test?
An ultrasound needs a follow-up test when the report cannot see the organ in question, when it finds something that needs measuring over time, or when the blood tests disagree with the scan. RadiologyInfo says a follow-up exam may be recommended to evaluate an issue further, to check for changes over time, or to see whether treatment is working. The NHS aorta programme is the clearest example of surveillance by size: yearly scans for a small aneurysm, every 3 months for a medium one, and a surgeon's referral at 5.5 cm.
For the biliary system the NIDDK sets out the ladder. Ultrasound finds gallstones; a CT scan can show complications such as infection or blockage but can miss some stones; MRI shows stones in the bile ducts; a HIDA scan tests whether the gallbladder contracts normally; and ERCP, which is more invasive, is kept for removing a stone lodged in the common bile duct. For the liver, the North Indian PLoS One study used FibroScan after ultrasound to grade fat and stiffness, and found fibrosis in 16.5% of urban and 5.2% of rural adults, which ultrasound alone had not separated.
Ask three questions when the report arrives: was every organ seen, is anything to be measured again and when, and does the finding explain the symptom. If the answer to the last is no, the doctor who ordered the scan decides the next test, not the ultrasound report. This guide is general information from the sources listed below, not medical advice; a registered doctor makes decisions with you.
