Breast — Reference values

Breast — Reference values: Minimum exam coverage, Location of a focal finding, Mass measurements, Background echotexture, Quick assistant — ultrasound BI-RADS.

The BI-RADS category should remain internationally standardized. Screening, recall, biopsy and follow-up pathways should follow local policy: ACR/United States, CBR/SBM/FEBRASGO in Brazil, EUSOBI/ESR in Europe and equivalent national guidance. With a palpable finding or clinical discordance, management should not be downgraded by negative imaging alone.

Measurements and reference values

Measurement	Usual value	Note
Minimum exam coverage	breasts and axillae when indicated	In Brazil, CBR/SBM/FEBRASGO recommend axillary extension when there is a nodule or suspicious lesion; billing/coding may be separate.complete: breasts documented and axilla evaluated when indicatedacceptable focused exam: focused request with clinical area clearly documentedincomplete: laterality, symptomatic area or indicated axilla not documentedSource: CBR/SBM/FEBRASGO 2018/2021 / ACR BI-RADS
Location of a focal finding	laterality + clock-face position + distance from nipple	For learners, prefer full wording: right breast, 10 o’clock, 35 mm from the nipple.well localized: laterality, clock-face and distanceacceptable in screening: quadrant/region when there is no focal lesionambiguous: no laterality or no relation to palpable areaSource: ACR whole-breast ultrasound parameter / RANZCR SBIR 2023
Mass measurements	3 dimensions in 2 orthogonal planes	Record the largest axis and the plane used; millimetres improve consistency in structured reporting.ideal: three measurements and two planespartial: two measurements when the third is not obtainedinsufficient: no measurement or no plane/locationSource: ACR whole-breast ultrasound parameter / RANZCR SBIR 2023
Background echotexture	fatty, fibroglandular or heterogeneous	Affects lesion conspicuity and should be reported in screening/supplemental ultrasound.described: composition/echotexture documentedcontextual: omitted in a simple focused examlimits interpretation: supplemental screening without echotextureSource: ACR whole-breast ultrasound parameter

Classifications and calculators

Quick assistant — ultrasound BI-RADS

Output	Color	Interpretation
BI-RADS 1–2	Green	Consensus normality/benignity when there is no clinical discordance.
BI-RADS 0 ou 3	Yellow	Incomplete assessment, probable benignity or a zone where guidelines may vary.
BI-RADS 4A–4C, 5 ou 6	Red	Suspicious, highly suspicious or biopsy-proven malignancy; usually requires tissue diagnosis or oncology pathway.

Use the assistant as a descriptor checklist. The final category should reflect the most suspicious finding and clinical-imaging concordance.

Source: ACR BI-RADS v2025 / RANZCR SBIR 2023 / StatPearls

ACR BI-RADS — detailed categories for ultrasound

Category	Color	Meaning / management	Risk
0	Yellow	Incomplete: needs additional imaging, comparison or diagnostic evaluation.	—
1	Green	Negative: routine pathway according to age, risk and local policy.	no suspicious finding
2	Green	Benign: simple cyst, typical intramammary node, stable post-operative finding or equivalent.	essentially benign
3	Yellow	Probably benign: short-interval follow-up, often 6 months, if clinical and imaging findings agree.	< 2%
4A	Red	Low suspicion: tissue diagnosis is generally indicated.	> 2–10%
4B	Red	Moderate suspicion: tissue diagnosis is indicated.	> 10–50%
4C	Red	High suspicion, but not yet classic for category 5.	> 50–< 95%
5	Red	Highly suggestive of malignancy: biopsy and oncology planning.	> 95%
6	Red	Biopsy-proven malignancy before definitive treatment.	confirmed

Category 3 should not be used for “doubt”. If there is relevant diagnostic uncertainty, clinical discordance or a suspicious finding, consider category 0 or 4 depending on the scenario.

Source: ACR BI-RADS v2025 / RANZCR SBIR 2023 / StatPearls

Ultrasound BI-RADS lexicon — mass descriptors

Descriptor	Green	Yellow	Red
Shape	oval or round if other findings are benign	isolated round shape or incomplete context	irregular
Orientation	parallel to skin	not described or difficult to assess	not parallel, taller than wide
Margin	circumscribed	indistinct in a possibly benign context	angular, microlobulated or spiculated
Echo pattern	anechoic typical of a simple cyst	isolated hypoechoic or heterogeneous	complex cystic-solid or suspicious solid
Posterior feature	posterior enhancement in a simple cyst	isolated shadowing may occur in benign findings	shadowing with suspicious margin/shape
Echogenic foci and calcifications	clearly benign macrocalcification	best correlated with mammography	foci within the mass or correlated suspicious calcifications
Associated findings	absent	explainable postoperative/inflammatory changes	distortion, skin/nipple retraction, edema or abnormal axillary node
Elasticity	soft as an adjunct finding	intermediate or heterogeneous	stiff as an adjunct finding; does not replace B-mode

The row color reflects the worst listed finding; combine descriptors, comparison with prior exams and indication.

Source: ACR BI-RADS v2025 ultrasound lexicon / Radiology Assistant summary / RANZCR SBIR

Technical protocol — breast and axilla

Situation	What to document	Color
Screening or complete bilateral exam	Quadrants, retroareolar region, composition/echotexture and axillae when indicated.	Green if complete
Focused exam	Document the exact complaint, laterality, position and relation to the palpable finding.	Yellow if justified
Focal finding	Two orthogonal projections, three measurements, laterality, clock-face position, distance from nipple and transducer orientation.	Red if incomplete in a suspicious lesion
Palpable mass with negative imaging	Apply clinical concordance: lack of imaging finding does not exclude biopsy if clinical concern is suspicious.	Yellow/red by clinical concern
Abnormal axillary node	Treat as a significant lesion: side, level/region, morphology, cortex, hilum, vascularity and associated breast lesion if present.	Red if suspicious

Source: ACR whole-breast ultrasound parameter / CBR-SBM-FEBRASGO / RANZCR SBIR

International and regional standards

Region	Practical standard	App application
Global / ACR	BI-RADS v2025 standardizes terminology, structure, categories and recommendations for mammography, ultrasound, MRI and contrast-enhanced mammography.	Use BI-RADS as the common core.
Brazil	Ultrasound is complementary to mammography after age 40 when indicated; before age 30 it is commonly the initial exam for a clinical abnormality. Axillae may require separate request/coding.	Show regional note and avoid omitting indicated axilla.
Europe / EUSOBI-ESR	Uses BI-RADS as common language; screening may be adjusted by density and risk, with specific recommendations for extremely dense breasts.	Keep BI-RADS category separate from local screening policy.
Australia and New Zealand / RANZCR	BI-RADS-based synoptic report, lesion by lesion, with clinical correlation and management recommendation.	Emphasize laterality, distance from nipple, three measurements and clinical concordance.
Other represented countries	When national policy differs, keep the BI-RADS category standardized and adapt only screening, recall, biopsy and follow-up interval.	Do not invent consensus where guidance diverges.

Source: ACR BI-RADS v2025 / CBR-SBM-FEBRASGO / EUSOBI-ESR / RANZCR SBIR / ACR Appropriateness Criteria

BI-RADS summary — breast ultrasound

Category	Meaning / management	Malig. risk
0	Incomplete — needs mammography, MRI, comparison or repeat evaluation	—
1	Negative — routine screening	0%
2	Benign finding	0%
3	Probably benign — 6-month follow-up	< 2%
4	Suspicious — biopsy (4A 2–10% · 4B 10–50% · 4C 50–95%)	2–95%
5	Highly suggestive — biopsy	> 95%
6	Biopsy-proven malignancy	—

Source: ACR BI-RADS / StatPearls

Teaching summary — suspicious signs in a breast mass

Feature	Suspicious finding
Orientation	Not parallel (taller-than-wide)
Margins	Spiculated, angular, microlobulated
Shape	Irregular
Posterior features	Acoustic shadowing
Echo/foci	Markedly hypoechoic; microcalcifications

Source: ACR BI-RADS US léxico

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