BI-RADS stands for Breast Imaging Reporting and Data System and was established by the American College of Radiology.

BIRADS is a scheme for putting the findings from mammogram screening (for breast cancer diagnosis) into a small number of well-defined categories. Although BIRADS started out for use with breast screening mammography, it was later adapted for use with Magnetic Resonance Imaging (MRI) and breast ultrasound (US) as well.

Breast imaging-reporting and data system (BIRADS) | Radiology ...
https://radiopaedia.org/.../breast-imaging-reporting-and-dat...
The BIRADS acronym stands for Breast Imaging-Reporting a. ... oil cysts · breast lipomas · fibroadenolipoma or mixed density hamartomas ... which is highly suggestive of malignancy, action should be taken; BIRADS VI: known biopsy proven malignancy. The vast majority of screening mammograms fall into BIRADS I or II 4.

http://www.radiologyassistant.nl/en/p53b4082c92130/bi-rads-f...
0 - need additional imaging
1 - negative
2 - benign
3 - probably benign
4 - suspicious
4a - low suspicion for malignacy
4b - moderate suspicion for malignacy
4c - hight suspicion for malignacy
5 - highly suggestive of malignacy
6 - known biopsy-proven



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Note added at 50 mins (2017-04-08 13:55:41 GMT)
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https://radiopaedia.org/articles/breast-density

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Note added at 52 mins (2017-04-08 13:57:20 GMT)
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In the BI-RADS edition 2013 the assignment of the breast composition is changed into a, b, c and d-categories followed by a description:

a- The breast are almost entirely fatty.
Mammography is highly sensitive in this setting.
b- There are scattered areas of fibroglandular density.
The term density describes the degree of x-ray attenuation of breast tissue but not discrete mammographic findings.
c- The breasts are heterogeneously dense, which may obscure small masses.
Some areas in the breasts are sufficiently dense to obscure small masses.
d - The breasts are extremely dense, which lowers the sensitivity of mammography.

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Note added at 6 days (2017-04-15 09:54:17 GMT) Post-grading
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