BI-RADS Level 0
Ultrasonography cannot fully evaluate the lesion
Further imaging is needed for diagnosis
Those with clinical signs but no signs on ultrasound
BI-RADS Level 1
No abnormalities on ultrasound, such as no masses, no structural disorders, no skin thickening, no microcalcifications, etc.
★Annual regular ultrasound review
BI-RADS grade 2
Benign sign, basically can exclude malignant
①Simple cyst
②Intramammary lymph nodes (may also belong to grade 1)
③Breast prosthesis implantation
④Age <25 years, consider fibroadenoma
⑤ fatty lobules (note differentiation from fibroadenoma)
★Regular review by ultrasound at 6-12 months
BI-RADS grade 3
Possible benign signs
①Solid oval-shaped mass with clear borders and aspect ratio <1 at age 25-39 years, benign possibility, risk of malignancy <2%
②Multiple complex cysts or clusters of small cysts
③ verrucous hyperplastic nodules (in the indeterminate category)
★ 3-6 months ultrasound periodic examinations and other further examinations
BI-RADS grade 3
l Age 25-39 years for initial ultrasound examination as grade 3.
l Family history
l Patient anxiety
l Reluctance to have regular examinations
l Solid masses
l Cystic solid masses that cannot be identified
l Cluster of small cysts
l ★ Biopsy recommended
BI-RADS Level 3 Evaluation after review
l Solid masses aged 35-39 years with initial ultrasound as grade 3, no family history, ultrasound review in 3-6 months
l 1. Mass shrinks and disappears → grade 2
2. No change in the mass, reexamined in 3-6 months, still no change → grade 2
3. The mass increases in size and changes to malignant signs → Grade 4 (biopsy)
BI-RADS grade 4
Suspected abnormality Risk of malignancy at this level 3 to 94%
① Fibroadenoma and other benign lesions that do not meet all ultrasound sonograms (malignant manifestations 1-3 in the benign-malignant differentiation table)
② solid mass lesions with benign ultrasound signs over 40 years of age, this lesion may not have characteristic breast cancer morphology, but it is of high incidence age and has the possibility of malignancy. 4A
★ Biopsy is recommended: needle aspiration cytology, hollow core needle aspiration biopsy, surgical biopsy, etc.
BI-RADS grade 5
Highly likely to be malignant
l Characteristic abnormal signs on ultrasound (>3 malignant signs in the benign-malignant solid mass differentiation table), risk of malignancy >95%
l Definitive treatment should be initiated. Hollow-core needle aspiration biopsy is appropriate when considering sentinel lymph node visualization and neoadjuvant chemotherapy
Ultrasound with characteristic abnormal signs (>3 malignant signs in the benign-malignant solid mass differential table)
BI-RADS grade 6
Biopsy-proven malignancy
l Used in biopsy-proven malignancy, pre-treatment imaging evaluation
l Primarily to evaluate imaging changes after prior biopsy or to monitor imaging changes before surgical resection and before and after neoadjuvant chemotherapy