How it works
A handheld probe sends sound waves into the body and listens for the echoes. A computer turns the echoes into moving pictures in real time. Ultrasound uses no ionising radiation.
Common uses
- Checking organs in the abdomen, such as the liver, gallbladder and kidneys.
- Looking at the heart (echocardiography) and blood flow in vessels (Doppler).
- Following a pregnancy.
- Guiding some procedures, such as taking a small tissue sample.
Preparing
Preparation depends on the area being examined — some abdominal scans need fasting, and some pelvic scans need a full bladder. Follow the instructions of the centre that booked your exam.
Sources
- Ultrasound (Sonography) — RadiologyInfo.org — ACR/RSNA. Checked 2026-09-26.
- Ultrasound — MedlinePlus — U.S. National Library of Medicine. Checked 2026-09-26.
Editorial update: 2026-09-26.
Medical disclaimer: this is a source-linked educational summary, not individual medical advice, diagnosis, prescription or interpretation of personal results. For severe or rapidly worsening symptoms, call 115.
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