Breast imaging-reporting and data system (BIRADS)

The BIRADS acronym stands for Breast Imaging-Reporting and Data System which is a widely accepted risk assesment and quality assurance tool in mammography, ultrasound or MRI. Part of the initial implementation was to make the rorting off mammograms more standardised and comprehensible to the non-radiologist reading the report.

This is not a unique system. There are other systems in use all over the world.

The latest version classifies lesions into 6 categories and are: 

• BIRADS 0 : incomplete : further imaging or information is required : e.g. compression, magnification, special mammographic views, ultrasound. This is also used when requesting previous images not available at the time of reading.
• BIRADS I : negative : symmetrical and no masses, architectural disturbances or suspicious calcifications present.
• BIRADS II : benign findings: interpreter may wish to describe a benign-appearing finding. e.g.
  • calcified fibroadenomas
  • multiple secretory calcifications
  • fat containing lesions such as 
    • oil cysts
    • breast lipomas
    • galactoceles and 
    • mixed density hamartomas
    • simple breast cysts
  • these all should have characteristic appearances, and may be labeled with confidence; the interpreter might wish to describe intra-mammary lymph nodes, implants, etc. while still concluding that there is no mammographic evidence suggesting malignancy.
• BIRADS III : probably benign : short interval follow-up suggested. The accent is on the word benign. 
• BIRADS IV : suspicious abnormality : 
  • there is a mammographic appearance which is suspicious for malignancy
  • biopsy should be considered for such a lesion
  • these can be further divided as
    • BIRADS IVa : low level of suspicion for malignancy
    • BIRADS IVb : intermediate suspicion for malignancy
    • BIRADS IVc : moderate suspicion for malignancy
• BIRADS V : there is a mammographic appearance 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

Risk of cancer

• BIRADS III : ~ 2%
• BIRADS IV : ~ 30%³
• BIRADS V : 95%

See also

• ACR 5 tier system
• Nottingham classification