Mammogram vs Ultrasound vs MRI: Which Breast Test?

Mammogram vs ultrasound vs MRI for breast cancer: at a glance

How mammograms, breast ultrasound and breast MRI compare, using NHS and NICE information.
Feature	Mammogram	Ultrasound	MRI
How it makes pictures NHS inform (Scotland): Breast cancer in women	A low-dose X-ray of the breast	Sound waves build a picture of the breast tissue	Magnetism builds detailed pictures of the body
Main use in breast care NHS: Tests and next steps for breast cancer in women	Breast clinic test for symptoms or after an abnormal screening result	Breast clinic test for symptoms or after an abnormal screening result	Used after a diagnosis to learn more about the cancer
Before treatment for invasive cancer NICE NG101: Pretreatment assessment	Used with examination and ultrasound to judge how far the cancer extends	Checks the armpit lymph nodes, with a needle sample if they look abnormal	Not routine; offered if the extent is unclear, breasts are dense, or for lobular cancer
Screening people at higher risk NICE CG164: Familial breast cancer – surveillance and early detection	Yearly mammograms offered to many women at moderate or high risk from age 40	Not routine; considered if MRI is unsuitable or results are hard to read	Yearly MRI offered to some high-risk women, such as BRCA carriers aged 30 to 49
Dense breasts NICE CG164: Familial breast cancer – surveillance and early detection	Might miss a cancer in dense breasts	Can be considered when mammogram or MRI results are hard to interpret	For some higher-risk women aged 50 to 69, used only if mammograms show dense breasts
Follow-up after treatment NICE NG101: Follow-up imaging	Every year for 5 years	Not used routinely for follow-up	Not used routinely for follow-up

Each row links to the NHS, NICE or WHO page it comes from. On a small screen, scroll the table sideways.

Key takeaways

A mammogram is a low-dose X-ray, breast ultrasound uses sound waves and MRI uses magnetism to make pictures. (NHS inform (Scotland): Breast cancer in women)
NHS breast screening uses mammograms, offered every 3 years to women aged 50 up to their 71st birthday. (NHS: Who breast screening is for)
Ultrasound scans do not use any radiation, unlike X-rays. (NHS: Ultrasound scan)
NICE recommends yearly MRI screening for some women at high risk, such as those aged 30 to 49 with a BRCA1 or BRCA2 gene change. (NICE CG164: Familial breast cancer – surveillance and early detection)
MRI is not used routinely before breast cancer surgery. NICE says it is offered when the extent of the cancer is unclear, when breast density makes mammograms hard to read, or for lobular cancer. (NICE NG101: Pretreatment assessment)

What happens during each test?

Each test is done in a different way:

Mammogram: the breast is placed on the X-ray machine and pressed between 2 pieces of plastic for a few seconds while each X-ray is taken. The NHS says this is often uncomfortable and sometimes painful, but the discomfort should not last long.
Ultrasound: a health professional puts gel on the skin and moves a small probe over the area. An ultrasound scan takes around 10 to 45 minutes.
MRI: the person lies still on a bed inside the scanner, which makes loud bangs and clicks. It usually takes 15 minutes to 1 hour, and a dye (contrast medium) may be injected to show more detail.

Sources: NHS: What happens at your breast screening appointment; NHS: Ultrasound scan; NHS: MRI scan

Do mammograms, ultrasound and MRI use radiation?

Mammograms are X-rays, so they use a small amount of radiation. The NHS says having a mammogram every 3 years for 20 years gives a very slightly higher chance of getting cancer over a lifetime, and NHS England says NHS machines use low doses to keep this risk as small as possible.

Ultrasound scans do not use any radiation. MRI uses strong magnetic fields and radio waves, and NHS inform says research has found no evidence that these pose a risk to the body.

Sources: NHS: Why breast screening is done; NHS England (GOV.UK): NHS breast screening – helping you decide; NHS: Ultrasound scan; NHS inform (Scotland): MRI scan

Which test is used for breast screening?

NHS breast screening uses mammograms to look for cancers that are too small to see or feel. Women aged 50 up to their 71st birthday are invited every 3 years.

People at higher risk, for example because of a BRCA gene change or a strong family history, may be screened earlier or more often, and some have MRI scans as well as mammograms. The NHS says MRI can give a clearer picture in younger people.

NICE does not recommend routine ultrasound screening for women at moderate or high risk, but says it can be considered when MRI is not suitable, for example because of claustrophobia, or when mammogram or MRI results are hard to interpret.

Sources: NHS: Breast screening (mammogram); NHS: Who breast screening is for; NHS: Why breast screening is done; NICE CG164: Familial breast cancer – surveillance and early detection

Why might a breast clinic use more than one test?

At a breast clinic, people may have a breast examination, a mammogram, an ultrasound and a biopsy, usually all in 1 visit. Not everyone needs all of these tests.

The tests add different information. Ultrasound is also used to scan the lymph nodes in the armpit, and MRI may be used to find out the size of a cancer and help decide on the operation. A biopsy, where a small sample of cells is taken, usually with a needle, is used to test for breast cancer and look for proteins that help decide treatment.

Sources: NHS: Tests and next steps for breast cancer in women; NHS inform (Scotland): Breast cancer in women

Frequently asked questions

Is an ultrasound better than a mammogram?

They do different jobs. A mammogram is a low-dose X-ray of the breast. A breast ultrasound uses sound waves to build up a picture of the breast tissue, and is also used to scan the lymph nodes in the armpit. After an examination, the doctor or nurse explains which tests are needed.

Source: NHS inform (Scotland): Breast cancer in women

Does a mammogram hurt?

The NHS says breast screening is often uncomfortable and sometimes painful for some people, but any discomfort should not last long. Each X-ray takes a few seconds. The mammographer is trained to help people feel more comfortable, and anyone can ask to stop at any time.

Source: NHS: What happens at your breast screening appointment

Does an MRI scan hurt?

NHS inform says an MRI scan is painless and safe. Some people feel a tingling or warm sensation that soon passes. The scanner is very loud, so earplugs or headphones are given, and people who are claustrophobic can ask a GP or consultant about a mild sedative well before the scan.

Source: NHS inform (Scotland): MRI scan

Who is offered breast MRI screening?

The NHS says some people have a higher chance of breast cancer, for example because several close relatives have had breast or ovarian cancer, or because of a gene change such as BRCA1, BRCA2 or TP53. Depending on their chance, they may be screened before 50, more often than every 3 years, or have MRI scans as well as mammograms.

Source: NHS: Why breast screening is done

Is a mammogram enough for dense breasts?

NICE notes that a mammogram might miss a cancer in women with dense breasts, and that further tests are more likely. For some women at higher risk aged 50 to 69, NICE says MRI should not be offered unless mammograms have shown a dense breast pattern. Anyone worried about breast density can talk to a GP.

Source: NICE CG164: Familial breast cancer – surveillance and early detection

Sources and references

This page is general information, not medical advice. A GP or doctor can advise on your own situation. Source links do not imply endorsement by the NHS or another organisation. See our editorial policy.

Mammogram vs ultrasound vs MRI for breast cancer