Breast Health · Comparing Tests

Breast Ultrasound vs Mammogram vs MRI

Three tests, three different jobs. What each one sees, where each falls short, and which is likely to answer your particular question.

Hospital imaging department corridor with scanner rooms visible through glass

These are not three grades of the same test, with MRI at the top. They answer different questions, and the right one depends on your age, your symptom and what has already been done. Choosing well matters more than choosing the most powerful machine.

One thing to be clear about upfront: we offer breast ultrasound only. Mammography and MRI are available through the NHS and hospital breast clinics, and if that is what your situation calls for, we will tell you so rather than scan you anyway.

Side by Side

How the three compare

Ultrasound Mammogram MRI
How it works Sound waves, no radiation Low-dose X-ray Magnetic field, usually with contrast injection
Best at Telling cysts from solid lumps; assessing a specific area you can feel Detecting microcalcifications; population screening Highest sensitivity; extent of known disease; high-risk screening
Dense breast tissue Works well Harder to read Works well
Typical age Any age, first-line under 40 Generally 40 and over Selected cases only
Radiation None Low dose None
In pregnancy Suitable Usually avoided Usually avoided
Main limitation Cannot see microcalcifications; not a screening test Less useful in dense tissue; uncomfortable for some More false alarms; costly; contrast needed
Available at IUS London Yes No No
Choosing

Which one answers your question

You can feel a lump and you are under 40. Ultrasound first. Younger breast tissue is denser, which is exactly where mammograms struggle and ultrasound performs well.

You can feel a lump and you are over 40. Usually both, and typically at a breast clinic: the mammogram surveys the whole breast, the ultrasound interrogates the specific area.

You have no symptoms and you are 50 to 71. The NHS breast screening programme invites you for mammography roughly every three years. That is the test with evidence behind it for screening — ultrasound is not a substitute, and going private instead of attending is a poor trade.

You were told you have dense breasts. Ultrasound can add a second look at tissue a mammogram reads less well. It is an addition, not a replacement.

You have a strong family history. Start with your GP, not a scan. Risk assessment may lead to genetic testing and, for those at high risk, an NHS surveillance programme that can include MRI from a younger age — a pathway no private ultrasound can stand in for.

Sonographer adjusting an ultrasound console with a greyscale scan image on the monitor
At IUS London

Where our scan fits

  1. 1
    A specific concernA lump, a tender area, an armpit swelling — ultrasound is designed for interrogating a place you can point to. 30-minute appointment, no referral, no preparation.
  2. 2
    Speed while you waitIf a clinic appointment is weeks away, a scan can tell you within days whether a lump is a simple cyst — without stopping the referral.
  3. 3
    Honest routingIf your question needs a mammogram, MRI or biopsy, we say so. Our report is written for a breast clinic to act on.
FAQs

Your questions answered

Is MRI simply the best test?
It is the most sensitive, which is not the same as best. High sensitivity also means more findings that turn out to be nothing, leading to further tests and anxiety. That trade is worth it for specific situations — high-risk surveillance, mapping known disease — and not for a routine question.
Can ultrasound replace my NHS mammogram?
No. Screening mammography is what the evidence supports for detecting cancers before symptoms appear, particularly through microcalcifications that ultrasound cannot see. Attend your screening invitation; use ultrasound for a specific concern.
Why is ultrasound better for younger women?
Younger breast tissue is denser, and dense tissue appears white on a mammogram — as do many abnormalities. Ultrasound is unaffected by density, which is why it is first-line under 40.
Do I need contrast for a breast ultrasound?
No. It uses sound waves only — no injection, no radiation, nothing to prepare. That is also why it is the imaging of choice in pregnancy.
What are microcalcifications and why do they matter?
Tiny calcium deposits that can be an early sign of change in the ducts, sometimes before any lump forms. Mammography detects them; ultrasound generally does not — one of the clearest examples of the two tests doing different jobs.
Can I just book all three privately?
You could, and it would usually be poor value and more anxiety. Tests chosen for a reason answer a question; tests stacked speculatively generate findings that need chasing. We offer ultrasound only, and we would rather point you to the right test than sell you the one we have.
Related

Where to go from here

SymptomsWhen to Get a Breast Ultrasound

Lumps, pain and changes — and which need your GP first.

Read the guide →TypesScreening vs Diagnostic

Two different jobs, and which one you actually need.

Read the guide →DetectionUltrasound and Early Detection

What the scan contributes, stated without overselling.

Read the guide →

The right test for the question

Breast ultrasound in a 30-minute appointment, findings explained on screen as we scan and the written report usually within two hours — and a straight answer if what you need is a test we do not offer.

From £189
Breast ultrasound scan

Breast ultrasound

5a Lucerne Mews
Kensington, London W8 4ED
3 mins from Notting Hill Gate

This article is general information about breast imaging, not individual medical advice. Any new breast change should be assessed by your GP, who can refer you to an NHS breast clinic — see NHS guidance on breast screening. We offer breast ultrasound only; mammography, MRI and biopsy are not available at IUS London.

Written and clinically reviewed by the HCPC-registered sonographers who perform this scan at IUS London — a CQC-registered diagnostic ultrasound clinic (Provider ID 1-2775844974). Your own findings are explained to you at the scan and set out in your report.

Author: Yianni Kiromitis, Senior Sonographer, HCPC RA38415 — over 20 years’ experience in NHS and private ultrasound
Medically reviewed: 9 August 2026