Breast Care A-Z · Procedure · BREASTMRI

Breast MRI

also: magnetic resonance imaging of the breast, breast magnetic resonance imaging, dynamic contrast-enhanced breast MRI

Breast MRI is a detailed scan that uses a magnetic field and a contrast injection — not X-rays — to image the breast, and it is used selectively rather than routinely. You may have been referred for one as part of your investigation, or be reading to understand when and why MRI is added to a mammogram and ultrasound.

Quick answers

Will the MRI hurt?

The scan itself is painless. The cannula for the contrast injection involves a small needle in the arm. The main discomfort is lying still face-down for 30–45 minutes; patients with claustrophobia sometimes find the scan stressful — let the radiology team know in advance and they can talk you through what to expect, or arrange sedation if needed.

Is the contrast dye safe?

Gadolinium contrast is well tolerated by the vast majority of patients. Allergic reactions are rare. Patients with severe kidney impairment may need an alternative approach. Pregnant patients are not given contrast unless absolutely necessary.

Will the MRI definitely tell me whether something is cancer?

No. MRI is a sensitive imaging test, but a definite diagnosis still needs a [biopsy](/glossary/core-biopsy/). The MRI tells the team whether there is something to biopsy and helps locate it.

RADIOLOGY · DIAGNOSTIC IMAGING PLATE LIII breast MRI magnetic resonance imaging · DCE-MRI · dynamic contrast-enhanced MRI high-sensitivity cross-sectional imaging using gadolinium contrast to detect breast malignancy in high-risk and dense breasts FIG 01 MRI Scanner Cross-Section — Patient Positioning & Contrast Enhancement breast coil AXIAL VIEW L R (lesion) i — MRI magnet bore ii — dedicated breast coil (bilateral imaging) iii — gadolinium contrast-enhancing lesion iv — contralateral normal breast (comparison) v — axillary nodes visible on MRI DCE-MRI Enhancement Kinetics SI Time post-contrast I II III Type I — persistent → benign Type II — plateau → indeterminate Type III — washout → suspicious When MRI is indicated • BRCA carrier annual screening • Dense breasts (heterogeneous / extremely dense) • Extent of disease pre-surgery • Neoadjuvant response monitoring • Occult primary (axillary node +ve, unknown primary) • Implant integrity assessment DCE-MRI kinetics Type I — persistent enhancement Likely benign Type II — plateau Indeterminate — monitor Type III — washout Suspicious for malignancy Concordance with morphology essential before biopsy decision (BI-RADS lexicon applies) FIG 02 Modality Comparison — MRI vs Mammography vs Ultrasound Parameter MRI Mammography Ultrasound Sensitivity ~90–95% ~84% ~80% Specificity ~72% ~91% ~80% Radiation None Yes (low dose) None Dense breasts Excellent Limited Moderate Cost High Low Low–moderate Availability Specialist centres Widespread Widespread Scan time 30–45 min 10–15 min 10–20 min Claustrophobia Risk None None Contrast Gadolinium IV None None Best use High-risk / extent Screening / calcifications Young / focal / USS-guided biopsy FIG 03 MRI-Detected Findings — Appearance & Action Finding MRI Appearance Action Mass lesion Rim / heterogeneous enhancement Biopsy if BI-RADS 4–5 Non-mass enhancement Segmental / linear pattern Biopsy Focus <5 mm enhancement 6-month follow-up Washout kinetics Type III curve Biopsy Implant rupture Intracapsular fold sign Surgical referral Extent assessment Multifocal disease mapped Surgical planning Neoadjuvant response Residual enhancement measured pCR vs partial response Background enhancement Varies with cycle Scan days 7–14 Normal No suspicious enhancement Routine recall FIG 04 Clinical Pathway — Breast MRI 1 Indication identified (BRCA / extent / dense) 2 Referral to breast MRI service 3 Gadolinium contrast IV + imaging 4 Radiologist reporting (BI-RADS) 5 MRI-guided biopsy if indicated 6 MDT integration + management plan FIG 05 Clinical Applications BRCA surveillance MRI Extent of disease MRI Neoadjuvant monitoring Occult primary MRI Implant integrity MRI-guided vacuum biopsy FIG 06 Key Statistics ~90–95% sensitivity vs ~84% mammography [1] Reduces re-excision rate when used pre-op [2] Annual MRI from age 30 for BRCA carriers [3] Specificity ~72% — higher false-positive rate [4] FIG 07 References 1. Sardanelli F et al. MRI sensitivity meta-analysis. Radiology 2015 2. Houssami N et al. Pre-op MRI meta-analysis. JAMA 2010;303:1759 3. NICE NG151. Familial breast cancer 2023 4. Turnbull L et al. COMICE trial. Lancet 2010;375:563 5. ACR BI-RADS Atlas 5th ed. 2013 Clinically authored by Dr Fiona Tsang-Wright , FRCS (Gen Surg) GMC 4549831 · ORCID 0000-0003-4801-026X
Visual Reference · Breast MRI
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Definition
A breast MRI is a detailed imaging test that uses a strong magnetic field and an injection of contrast dye to produce three-dimensional pictures of the breast tissue, used in specific situations where mammogram and ultrasound cannot give a complete picture.
≥ 30% Lifetime breast cancer risk threshold for adjunct MRI in NICE CG164 high-risk surveillance 2

Common questions The questions patients ask first

Will the MRI hurt?
The scan itself is painless. The cannula for the contrast injection involves a small needle in the arm. The main discomfort is lying still face-down for 30–45 minutes; patients with claustrophobia sometimes find the scan stressful — let the radiology team know in advance and they can talk you through what to expect, or arrange sedation if needed.
Is the contrast dye safe?
Gadolinium contrast is well tolerated by the vast majority of patients. Allergic reactions are rare. Patients with severe kidney impairment may need an alternative approach. Pregnant patients are not given contrast unless absolutely necessary.
Will the MRI definitely tell me whether something is cancer?
No. MRI is a sensitive imaging test, but a definite diagnosis still needs a [biopsy](/glossary/core-biopsy/). The MRI tells the team whether there is something to biopsy and helps locate it.
Why isn't MRI used for routine breast screening?
Because it is highly sensitive but less specific — it picks up many benign findings that need follow-up biopsies. For the general population, the trade-off favours mammography (which has a better balance of sensitivity and specificity for population screening). For high-risk groups, the trade-off favours MRI, which is why those patients are offered it.
Can I have a breast MRI privately?
Yes — private breast imaging including MRI is widely available. Pre-authorisation is usually arranged with your insurer if you are using insurance. Self-pay options are also available. See [fees and insurance](/fees-insurance/).

A breast MRI is a detailed imaging test that uses a strong magnetic field and an injection of contrast dye to produce three-dimensional pictures of the breast tissue, used in specific situations where mammogram and ultrasound cannot give a complete picture.

Breast MRI is the third imaging pillar after mammogram and ultrasound. It is highly sensitive — particularly good at detecting cancers that other tests can miss — but is not used routinely because it can also pick up benign findings that need additional investigation. MRI is reserved for specific clinical situations: high-risk screening, problem-solving, neoadjuvant chemotherapy monitoring, and post-surgical assessment.

Orientation Why you might be reading about this

You may have been referred for a breast MRI as part of your investigation, or you are reading to understand when and why MRI is added to other imaging. The test is detailed and time-consuming compared to mammogram and ultrasound, and it is used selectively rather than routinely. This page explains what an MRI involves and when it is helpful.

Related terms: Mammogram · Breast ultrasound · Core biopsy · Invasive lobular carcinoma · BRCA

The procedure How a breast MRI is done

Breast MRI uses a powerful magnet and radio waves to create detailed cross-sectional images of the breast. The patient lies face-down on a specially designed table, with the breasts positioned through openings into a coil that improves image quality. The table then slides into the MRI scanner.

A contrast dye (gadolinium) is given through a small intravenous cannula partway through the scan. The contrast highlights areas with increased blood flow — a feature of many cancers — and is what makes MRI so sensitive for breast cancer detection.

The scan itself takes around 30–45 minutes4. The MRI machine is loud (a series of loud knocking noises during scanning), and patients are given headphones with music for comfort. There is no radiation involved.

When it’s used When breast MRI is used

Breast MRI is reserved for specific situations rather than used routinely:

1. High-risk screening

Patients at substantially raised lifetime breast cancer risk — particularly BRCA1/BRCA2 mutation carriers and other high-risk gene carriers — are offered annual MRI from age 30, often with annual mammography added from age 4012. MRI is more sensitive than mammography in younger women with denser breast tissue, where many high-risk patients fall5.

2. Newly diagnosed cancer — staging and surgical planning

For some newly diagnosed cancers, MRI is added to the standard mammogram and ultrasound to map the true extent of the disease in the breast and check the other breast3. This is most often used for:

  • Invasive lobular carcinoma, which is often more extensive than mammogram suggests because of its diffuse growth pattern3.
  • Patients with very dense breast tissue, where mammographic assessment is limited35.
  • Cases where there is a discrepancy between examination findings and standard imaging3.

The MRI sometimes changes the surgical plan — for example, identifying a second area in the same breast that needs biopsy or surgery, or showing that disease is more extensive than thought and that mastectomy is the better operation rather than lumpectomy.

3. Monitoring response to neoadjuvant chemotherapy

When chemotherapy is given before surgery (neoadjuvant chemotherapy), MRI is the most accurate way to assess how the cancer has responded. The change in the size and appearance of the cancer on MRI guides the surgical plan.

4. Implant assessment

For patients with breast implants, MRI is used to assess implant integrity — particularly to look for silicone implant rupture, which can be hard to detect on examination or other imaging. MRI is also part of the assessment when there is concern about breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL), a rare condition associated with certain textured implants.

5. Problem-solving in difficult cases

When mammogram, ultrasound, and clinical examination give an unclear picture — for example, where examination suggests a lump but imaging cannot find it, or where there is a clinical suspicion of recurrence after previous breast cancer treatment — MRI is sometimes used to resolve the question.

Limitations What MRI cannot do well

For all its strengths, breast MRI has specific limitations:

  • It does not pick up microcalcifications as well as mammography, so it does not replace mammograms for screening or for diagnosis of suspected DCIS.
  • It is highly sensitive but less specific — it picks up many benign findings (fibroadenomas, cysts, normal hormonal changes) as enhancing areas, which can lead to additional biopsies that turn out to be benign. This is one reason MRI is not used for routine screening.
  • It requires contrast dye, which is not appropriate in pregnancy and needs caution in patients with kidney impairment.
  • It is more expensive and time-consuming than mammogram or ultrasound, and access varies between hospitals.

Afterwards What happens after the MRI

The radiologist reports the scan within a few days. If the MRI identifies an area of concern that was not visible on previous imaging, the next step is usually a second-look ultrasound to see whether the area is visible on ultrasound, followed by a biopsy under ultrasound guidance if appropriate. If the area is visible only on MRI, an MRI-guided biopsy can be arranged at specialist centres.

The MRI report and any subsequent biopsy are reviewed at the multidisciplinary team meeting before treatment planning is finalised.

At consultation What to discuss at consultation

If breast MRI has been recommended:

  • Why MRI is being done — what specific question it is intended to answer.
  • What the next step is if the MRI finds something that was not visible on previous imaging.
  • Whether the MRI might delay surgery — most do not delay treatment significantly, but a finding that needs further biopsy can add a couple of weeks.
  • For high-risk screening, the surveillance schedule and what to do between scans.

Resources Further reading

Sources & guidance

Every figure on this page is anchored to a published source. Tap a number in the text or below to jump to the reference.

  1. guideline National Institute for Health and Care Excellence (NICE). Familial breast cancer: classification, care and managing breast cancer and related risks in people with a family history of breast cancer (CG164). London: NICE. 2013 ;Last updated 2023 https://www.nice.org.uk/guidance/cg164 Cited for: UK indications and surveillance schedule for high-risk breast MRI screening (BRCA1/BRCA2 carriers from age 30; high lifetime-risk thresholds).
  2. guideline Saslow D, Boetes C, Burke W, et al. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA: A Cancer Journal for Clinicians. 2007 ;57(2):75–89 doi:10.3322/canjclin.57.2.75 Cited for: Lifetime risk ≥20–25% threshold for adjunct MRI screening (international corroboration of NICE CG164).
  3. guideline National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management (NG101). London: NICE. 2018 ;Last updated 2024; recommendation 1.2.4 — pre-operative MRI https://www.nice.org.uk/guidance/ng101 Cited for: Indications for staging MRI: invasive lobular carcinoma; discrepancy between examination and standard imaging; consideration in dense breasts where assessment is limited.
  4. guidance Royal College of Radiologists. Guidance on screening and symptomatic breast imaging. 4th edition. London: RCR. 2019 https://www.rcr.ac.uk Cited for: UK practice for breast MRI: dynamic contrast-enhanced protocol, 30–45 minute scan, prone positioning, gadolinium safety considerations.
  5. guidance Mann RM, Athanasiou A, Baltzer PAT, et al. (European Society of Breast Imaging). Breast cancer screening in women with extremely dense breasts: recommendations of the European Society of Breast Imaging (EUSOBI). European Radiology. 2022 ;32(6):4036–4045 doi:10.1007/s00330-022-08617-6 Cited for: Higher sensitivity of MRI vs mammography in dense breasts; rationale for supplemental MRI in selected dense-breast populations.