While BI-RADS is a
quality control system, in day-to-day usage the term
BI-RADS refers to the mammography assessment categories. These are standardized numerical codes typically assigned by a
radiologist after interpreting a mammogram. This allows for concise and unambiguous understanding of patient records between multiple doctors and medical facilities. The assessment categories were initially developed for mammography and later adapted for use with MRI and ultrasound findings. The summary of each category, given below, is nearly identical for all three modalities. Category 6 was added in the 4th edition of the BI-RADS. BI-RADS assessment categories are: • 0: Incomplete • 1: Negative • 2: Benign • 3: Probably benign • 4: Suspicious • 5: Highly suggestive of malignancy • 6: Known biopsy-proven malignancy An incomplete (BI-RADS 0) classification warrants either an effort to ascertain prior imaging for comparison, or to call the patient back for additional views and/or higher quality films. A BI-RADS classification of 4 or 5 warrants
biopsy to further evaluate the offending lesion. Some experts believe that the single BI-RADS 4 classification does not adequately communicate the risk of cancer to doctors and recommend a subclassification scheme: • 4A: low suspicion of malignancy, about > 2% to ≤ 10% likelihood of malignancy • 4B: intermediate suspicion of malignancy, about > 10% to ≤ 50% likelihood of malignancy • 4C: moderate concern, but not classic for malignancy, about > 50% to < 95% likelihood of malignancy ==Breast composition categories==