Mammogram analysis requires expertise and frequent practice. Multidisciplinary discussion, together with regular confrontation with clinical examination, ultrasound examinations and surgical results, enable the radiologist (or rather the team of radiologists) to obtain an increasingly more secure diagnosis.
The American College of Radiology has put forward recommendations, nowadays largely used, for interpreting mammograms, particularly during screening campaigns, and also proposes logical therapeutic attitudes.
The aim of this general description is to explain the interpretation difficulties encountered due to overall breast density which may obscure small lesions situated within normal tissue. The presence of an implant should also be noted.
The ACR distinguishes 4 situations:
- entirely fatty breast,
- rare fibroglandular densities,
- heterogeneously dense mammary tissue (potentially obscuring the diagnosis of small lesions),
- very dense mammary gland (great difficulty in the detection of tumoral lesions).
The following criteria should always be described:
- masses (size, shape, associated lesions, location, potential modifications since previous examinations),
- calcifications (morphology, distribution, location, size, focus, associated lesions),
- architectural modifications,
- any other abnormality.
The overall impression and the necessity for further examinations or biopsy should be provided for each described lesion.
Result classification according to American College of Radiology.
| Category |
Attitude |
Description |
0 |
Additional Imaging |
Requires additional imaging evaluation
and/or prior mammogram for comparison - Impossibility to give an assessment
- Views of poor quality |
1 |
Negative |
There is nothing to report. The breasts
are symmetric and no masses, architectural distortion or suspicious calcifications
are present. |
2 |
Benign findings |
This is a “normal”
assessment, but here, the interpreter chooses to describe a benign finding
in the mammography report. Involuting, calcified fibroadenomas, multiple
secretory calcifications, fat-containing lesions such as oil cysts, lipomas,
galactoceles and mixed-densityhamartomas all have characteristically benign
appearances, and may be labelled with confidence. The interpreter may
also choose to describe intramammary lymph nodes, vascular calcifications,
implants or architectural distortion clearly related to prior surgery
while still concluding that there is no mammographic evidence of malignancy. |
3 |
Follow-up |
The findings are probably benign and
are not expected to change over the follow-up interval, but the radiologist
would prefer to establish its stability. Three specific findings are described
as being probably benign (the non-calcified circumscribed solid mass,
the focal asymmetry and the cluster of round punctuate calcifications).
Initial short-term follow-up (6 months) |
4 |
Suspicion |
This category is reserved for findings
that do not have the classic appearance of malignancy but have a wide
range of probability of malignancy that is greater than those in Category
3. Most recommendations of breast biopsies will be placed within this
category. |
5 |
Positive |
These lesions have a high probability
(=95%) of being cancer. This category contains lesions for which one-stage
surgical treatment could be considered without preliminary biopsy. However,
current oncological management may require percutaneous tissue sampling
as, for example, when sentinel node imaging is included in surgical treatment
or when neoadjuvant chemotherapy is administered at the outset. |
| 6 | Proven Malignancy |
This category is reserved for lesions identified
on the imaging study with biopsy proof of malignancy prior to definitive
therapy. |