Ultrasound scans

An ultrasound scan is a common imaging test that uses sound waves to produce pictures of structures inside the body. In UK general practice, ultrasound is often the first imaging test considered because it is safe, widely available, and can be very helpful for specific symptoms.

This page explains how ultrasound works, what it can and cannot show, how GPs decide when it is appropriate, and what to expect before and after your scan.

These articles are intended as educational sources, not diagnostic nor taking place of a proper medical assessment. If you need help or advice on medical scans, please book a GP appointment.

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How ultrasound scans commonly help in GP care

Ultrasound is most helpful when a GP has a focused clinical question, for example:

Is there a gallstone or inflammation in the gallbladder?
Is there a kidney stone or urinary obstruction?
Is there a cyst, fibroid, or ovarian change that fits the symptoms?
Is there a hernia, fluid collection, or soft tissue lump that needs clarification?
Is there inflammation in a tendon or bursa, particularly around the shoulder or knee?
Is there a blood flow issue that needs assessment, such as a suspected clot in selected cases?

Ultrasound is not a general “full body check”. It is a targeted test used to answer specific questions.

What an ultrasound can and cannot show

What ultrasound is good at

Ultrasound is particularly useful for assessing:

Abdominal organs such as the liver, gallbladder, kidneys, and bladder
Pelvic organs such as the uterus and ovaries
Soft tissues such as tendons, muscles, bursae, and superficial lumps
Fluid collections
Blood flow when Doppler ultrasound is used

What ultrasound is less helpful for

Ultrasound may not be the best test for:

Some bowel conditions, depending on location and body habitus
Deep structures obscured by gas, bone, or certain tissues
Detailed assessment of the brain, lungs, or bones
Some causes of back pain, where MRI may be more appropriate if imaging is needed

A GP will choose imaging based on the symptom pattern and what question needs answering.

Common reasons a GP may recommend an ultrasound

Examples include:

Abdominal symptoms

Right upper abdominal pain, suspected gallstones
Flank pain, suspected kidney obstruction
Persistent abdominal pain with a clear clinical question
Investigation of abnormal liver or kidney findings, when clinically indicated

Pelvic symptoms

Pelvic pain
Heavy or irregular bleeding
Suspected fibroids or ovarian cysts
Assessment in early pregnancy symptoms, where appropriate pathways apply

Lumps and soft tissue concerns

New lumps under the skin
Suspected hernia
Swellings that may be cysts or fluid collections

Musculoskeletal and tendon problems

Suspected rotator cuff issues
Bursitis
Tendon problems in selected cases

Ultrasound is used when the result is likely to guide treatment, referral, or reassurance in context.

How a GP decides whether ultrasound is appropriate

A GP will usually consider:

Your symptoms, duration, and pattern
Examination findings where available
Whether there are red flag features
Whether ultrasound findings would change what happens next
Whether a different test is more appropriate

For the GP approach to imaging decisions, see:
How GPs use medical imaging in practice

Preparing for an ultrasound scan

Preparation depends on the type of ultrasound.

Abdominal ultrasound

You may be asked to avoid food for several hours beforehand. This can improve visibility of the gallbladder and upper abdominal organs.

Pelvic ultrasound

You may be asked to attend with a full bladder for some scans. In some cases, a transvaginal ultrasound may be recommended, which typically does not require a full bladder.

Soft tissue or musculoskeletal ultrasound

Often no special preparation is required.

Your scan provider should give clear instructions. If instructions are unclear, it is worth checking before attending.

Are ultrasound scans safe?

Ultrasound does not use ionising radiation. It is generally considered very safe, including in pregnancy, when clinically indicated.

The main “risks” are not physical harms but practical limitations, such as inconclusive findings or incidental findings that may need follow-up.

Limitations and why results can be unclear

Ultrasound quality can be affected by:

Body habitus
Bowel gas
The depth of the structure being assessed
The skill and experience of the operator
Whether the organ is fully visualised during the scan

A normal or unclear ultrasound does not necessarily mean there is no problem. It means the scan did not show a structural cause that ultrasound can detect.

What happens after an ultrasound

If the scan explains symptoms

A GP may:

Confirm a working diagnosis
Recommend treatment
Arrange follow-up
Refer to specialist care if appropriate

If the scan is normal