Breast Care A-Z · Procedure · ULTRASOUND

Breast ultrasound

also: breast ultrasound scan, breast US, sonogram of the breast, ultrasonography

Breast ultrasound uses high-frequency sound waves — no X-rays — to image breast tissue, and it is especially useful in younger, denser breasts and for telling solid lumps from fluid-filled cysts. You may have been told you need one, or had one at your one-stop clinic visit; this page explains what it can and cannot show.

Quick answers

Does breast ultrasound use radiation?

No. Ultrasound uses sound waves, not X-rays or any other ionising radiation. It is safe in pregnancy and at any age.

Will the ultrasound hurt?

No. The probe is moved over the breast with gentle pressure, with gel between the probe and the skin. Most patients find ultrasound the most comfortable part of a breast clinic visit. Mild discomfort is occasionally reported when an area is already tender, such as over an inflamed cyst.

Why am I having a mammogram and an ultrasound?

Because the two tests show different things. Mammograms are particularly good at picking up calcifications and small early cancers in less dense tissue; ultrasound is good at characterising lumps (solid versus fluid-filled) and at imaging dense tissue. The combination is more sensitive than either alone, which is why both are used in patients over about 40 with a new symptom.

Breast Ultrasound -- Breastory Encyclopaedia Plate LXVI Breast ultrasonography: BI-RADS USS categories, benign vs malignant features, USS-guided procedures, and supplemental screening. RADIOLOGY · DIAGNOSTIC IMAGING PLATE LXVI breast ultrasound breast ultrasonography · USS breast real-time sound-wave imaging to characterise breast masses, evaluate dense tissue, guide biopsies, and assess implants FIG 01 — USS probe and image: anechoic cyst vs suspicious solid mass USS linear transducer 7–18 MHz skin surface (coupling gel) Cyst: anechoic, smooth walls, PEE anechoic posterior enhancement Mass: irregular, shadowing hetero- geneous posterior shadowing USS screen — schematic representation Cyst: anechoic, smooth, PEE Mass: irregular, shadowing i — ultrasound transducer (7–18 MHz linear probe) ii — skin entry surface (coupling gel applied) iii — anechoic cyst (black oval, posterior enhancement / PEE) iv — solid lesion (heterogeneous, irregular margins, spiculated) v — posterior acoustic shadowing (malignant) vs enhancement (benign cyst) BI-RADS USS categories U1 Negative U2 Benign U3 Probably benign (short-interval f/u) U4 Suspicious — biopsy U5 Highly suspicious — biopsy USS: roles and limitations Supplemental USS Dense breasts; no radiation; real-time USS-guided biopsy Core / FNA in real time; accurate USS limitations Operator-dependent; misses calcifications FIG 02 — Benign vs malignant USS features (BI-RADS criteria) Feature Benign Malignant Shape Oval / round Irregular Margins Circumscribed Spiculated / angular Orientation Parallel (wider than tall) Non-parallel (taller than wide) Echo pattern Anechoic or homogeneous Heterogeneous Posterior Enhancement (PEE) Shadowing Vascularity Avascular Increased / chaotic Compressibility Compressible (cyst) Rigid BI-RADS U2 U4–U5 Examples Simple cyst, fibroadenoma IDC, ILC Action Reassure / routine follow-up Core biopsy FIG 03 — USS-guided procedures Procedure Technique Indication FNA 21–23G needle, real-time Cyst aspiration, cytology Core biopsy 14G Tru-Cut, real-time Solid lesion histology Vacuum-assisted biopsy 7–11G, motorised B3 lesions, calcifications Clip placement Metallic marker post-biopsy Pre-neoadjuvant marking Preoperative localisation Wire or RADS clip Non-palpable lesion marking Abscess drainage USS-guided aspiration Breast abscess Lymph node sampling Axillary node FNA Pre-op staging Haematoma aspiration USS-guided drain Post-surgical haematoma Cyst injection Steroid into cyst Recurrent symptomatic cysts FIG 04 — USS pathway from referral to management 1 Referral (palpable mass / dense breasts / 2 USS performed (bilateral or targeted) 3 BI-RADS U category assigned 4 Biopsy if U3–U5 (USS-guided core biopsy) 5 Histology (B classification) 6 MDT + management plan FIG 05 — USS clinical scenarios Simple cyst (U2 / anechoic) Fibroadenoma (U2 / U3) Suspicious mass (U4–U5) USS-guided core biopsy Supplemental screening USS Implant integrity assessment FIG 06 — Key statistics Sensitivity ~78% for palpable lesions [1] Supplemental USS detects 2–4 extra cancers / 1000 in dense breasts [2] USS-guided biopsy accuracy >99% [3] Dose-free — no ionising radiation [4] FIG 07 — References References 1. Kolb TM et al. Ultrasound sensitivity. Radiology 2002;225:165 2. Berg WA et al. ACRIN 6666 trial. JAMA 2012;307:1394 3. NICE NG12. Suspected cancer 2023 4. ACR BI-RADS Atlas 5th ed. 2013 5. NHS BSP. Ultrasound guidelines 2022 Clinically authored by Dr Fiona Tsang-Wright , FRCS (Gen Surg) GMC 4549831 · ORCID 0000-0003-4801-026X
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Definition
A breast ultrasound is a painless imaging test that uses high-frequency sound waves to produce live images of the breast tissue, used to investigate a lump or other breast change and to guide biopsies of suspicious areas.

Common questions The questions patients ask first

Does breast ultrasound use radiation?
No. Ultrasound uses sound waves, not X-rays or any other ionising radiation. It is safe in pregnancy and at any age.
Will the ultrasound hurt?
No. The probe is moved over the breast with gentle pressure, with gel between the probe and the skin. Most patients find ultrasound the most comfortable part of a breast clinic visit. Mild discomfort is occasionally reported when an area is already tender, such as over an inflamed cyst.
Why am I having a mammogram and an ultrasound?
Because the two tests show different things2. Mammograms are particularly good at picking up calcifications and small early cancers in less dense tissue; ultrasound is good at characterising lumps (solid versus fluid-filled) and at imaging dense tissue3. The combination is more sensitive than either alone, which is why both are used in patients over about 40 with a new symptom1.
Can ultrasound tell if a lump is cancer?
Ultrasound features can suggest whether a lump is more likely to be benign or malignant — for example, a smooth oval lesion looks different from an irregular spiculated one — but the definitive answer requires a biopsy. The role of ultrasound is to characterise the lump well enough to decide whether a biopsy is needed and to guide it accurately.

A breast ultrasound is a painless imaging test that uses high-frequency sound waves to produce live images of the breast tissue, used to investigate a lump or other breast change and to guide biopsies of suspicious areas.

Breast ultrasound is one of the two main imaging tests used in breast clinics, alongside the mammogram2. It uses no radiation4, takes around 10–15 minutes, and gives results immediately. It is particularly useful for distinguishing fluid-filled lumps (cysts) from solid lumps3, and for guiding needle biopsies.

Orientation Why you might be reading about this

You have probably been told that you need a breast ultrasound, or one was done at your one-stop clinic visit. This page explains what an ultrasound is, what it can show, what it cannot show, and how it complements the other imaging tests used in breast clinics.

Related terms: Mammogram · Breast lump · Breast cyst · Core biopsy · Triple assessment

The procedure How a breast ultrasound is done

Ultrasound is a real-time imaging technique that uses high-frequency sound waves sent into the breast tissue from a hand-held probe (a transducer). The waves bounce back from different structures inside the breast, and the machine builds these echoes into a live image on a screen.

What happens at the appointment:

  1. You lie on the examination couch with your arm raised on the side being scanned.
  2. A small amount of clear water-based gel is applied to the skin — this allows the sound waves to pass through cleanly. The gel feels cool but is not sticky once wiped off.
  3. The radiologist or sonographer moves the probe over the breast and the area under the arm, watching the image on screen and capturing still pictures of any findings.
  4. The whole scan takes 10–15 minutes; longer if both breasts are being scanned or if a biopsy is performed afterwards.

There is no radiation, no compression, and no injection. Most patients find it one of the more comfortable parts of a breast clinic visit.

Strengths What ultrasound is good at showing

Ultrasound has specific strengths:

  • Distinguishing solid from fluid-filled lumps — a key clinical question3. A simple cyst appears as a well-defined dark space; a solid lump (such as a fibroadenoma or cancer) appears as a tissue-density area. This distinction is often the most useful single piece of information from the scan.
  • Imaging dense breasts — younger women have denser breast tissue, which can make mammograms harder to read. Ultrasound is not affected by breast density and is the first-line imaging test for most patients under 402.
  • Looking at the lymph nodes under the arm — ultrasound can image the axillary nodes and identify any with abnormal features that warrant a biopsy.
  • Guiding needle procedures — biopsies, cyst aspirations, and seed/wire localisations are all done under ultrasound guidance. The radiologist or surgeon watches the needle in real time.
  • Following lesions over time — for example, monitoring the size of a fibroadenoma at intervals.

Limitations What ultrasound cannot reliably show

  • Microcalcifications — clusters of tiny calcium deposits that may indicate DCIS or early cancer. Mammograms see these clearly; ultrasound usually does not.
  • The whole breast as a screening test — ultrasound is operator-dependent and time-intensive, and it is not used as a routine population screening tool. Mammography is the standard for screening.
  • Distinguishing benign from malignant solid lumps with certainty — ultrasound features are suggestive but not diagnostic. A solid lump that warrants confirmation needs a core biopsy.

For these reasons, ultrasound is usually performed alongside a mammogram in patients over 40 — the two tests are complementary, each strong where the other is weak2. Younger patients are often imaged with ultrasound alone in the first instance12.

One-stop role Ultrasound in the one-stop clinic

In a one-stop clinic visit, ultrasound is typically the imaging test that immediately follows the clinical examination. The radiologist and the breast surgeon discuss the imaging findings while you are still on the couch, and any biopsy that is needed is performed in the same visit under ultrasound guidance. This is one of the things that makes one-stop pathway possible — ultrasound results are immediate and the radiologist is present.

At consultation What to discuss at consultation

For most patients, a breast ultrasound is an interim step rather than a destination — it produces a finding that becomes part of the wider triple assessment. Things worth checking after the scan:

  • What the scan showed and what the radiologist’s assessment is.
  • Whether further imaging (mammogram, MRI) is needed.
  • Whether a biopsy is recommended, and why.
  • The plan from here — most patients leave the one-stop visit with a clear next step.

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). Suspected cancer: recognition and referral (NG12). London: NICE. 2015 ;Last updated 2023 https://www.nice.org.uk/guidance/ng12 Cited for: UK two-week-wait referral pathway and triple-assessment standard.
  2. 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 ultrasound: first-line in symptomatic patients under 40, complementary to mammography from 40, image-guided biopsy.
  3. reference text American College of Radiology (ACR). Breast Imaging Reporting and Data System (BI-RADS) Atlas, 5th edition — Ultrasound. Reston, VA: ACR. 2013 https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Reporting-and-Data-Systems/BI-RADS Cited for: BI-RADS lexicon for ultrasound (mass shape, orientation, margin, echo pattern); cyst categorisation (simple, complicated, complex).
  4. patient NHS. Ultrasound scan. nhs.uk. 2024 https://www.nhs.uk/tests-and-treatments/ultrasound-scan/ Cited for: Patient-facing context for ultrasound (no radiation, no compression); not used for clinical claims.