Radiologists assign certain categories to the mammography findings.
The most commonly used classification system is the one devised by The American College of Radiology (ACR http://www.acr.org) and is called the Breast Imaging Reporting and Database System (BI-RADS®). This system enables the radiologist or clinician choose from specific diagnostic strategies.
1) These are the classifications that apply when the mammogram returns no worrisome results and there are no supplementary tests required:
A.C.R.1: Denotes a normal mammography.
A.C.R.2: Denotes benign findings (fibroadenoma, macro-calcifications – benign, lymph nodes) that do not require any supplementary cyto-histology tests.
2) These are the classifications that apply when the mammogram returns abnormal results and there are supplementary tests required:
A.C.R.3: Denotes an abnormality that is probably benign, but necessitates: short term monitoring (in the form or a further mammogram 3-6 months later in order to study any developments), a cytology specimen study, or a biopsy.
A.C.R.4: Denotes an abnormality that is more or less unidentified but is suspicious. It requires histological verification (or a biopsy). There are three subclasses of A.C.R.4, a,b,and c and these represent a rising probability of cancer.
A.C.R.5: Denotes an abnormality that suggests malignancy and necessitates further investigation with for example, a biopsy (histological exam).
A.C.R.0: This classification indicates the need for: additional imaging evaluation or re-evaluation of existing images or a second opinion before a classification can be applied.
3) This is the classification that applies when breast cancer is detected from the results of a biopsy:
A.C.R.6: Applies when histology results indicate the presence of a cancer that requires treatment.