The atlas was designed to ensure that breast findings are appropriately analyzed and correctly designated to one of seven BI-RADS categories, each of which implies a specific management recommendation. BI-RADS 3 was created to help reduce the number of false-positive biopsies, while maintaining a high rate of early cancer detection. A BI-RADS 3 category should only be given after a complete diagnostic work-up, which may include additional mammographic views and often sonographic evaluation. Finally, BI-RADS 3 is not to be used as a category of uncertainty and should not be used as a safety net to place findings that a radiologist is unsure whether to pass as benign or biopsy.
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It also facilitates outcome monitoring and quality assessment. It contains a lexicon for standardized terminology descriptors for mammography, breast US and MRI, as well as chapters on Report Organization and Guidance Chapters for use in daily practice. The table shows a summary of the mammography and ultrasound lexicon. Enlarge the table by clicking on the image.
First describe the breast composition. When there is a significant finding use the descriptors in the table. The ultrasound lexicon has many similarities to the mammography lexicon, but there are some descriptors that are specific for ultrasound. We will first discuss the breast imaging lexicon of mammography and ultrasound and then discuss in more detail the final assessment categories and the do's and don'ts in these categories.
In BI-RADS the use of percentages is discouraged, because in individual cases it is more important to take into account the chance that a mass can be obscured by fibroglandular tissue than the percentage of breast density as an indicator for breast cancer risk. In the BI-RADS edition the assignment of the breast composition is changed into a, b, c and d-categories followed by a description:. The fibroglandular tissue in the upper part is sufficiently dense to obscure small masses.
So it is called c , because small masses can be obscured. A 'Mass' is a space occupying 3D lesion seen in two different projections. If a potential mass is seen in only a single projection it should be called a 'asymmetry' until its three-dimensionality is confirmed. The images show a fat-containing lesion with a popcorn-like calcification. All fat-containing lesions are typically benign.
These image-findings are diagnostic for a hamartoma - also known as fibroadenolipoma. Always make sure that a mass that is found on physical examination is the same as the mass that is found with mammography or ultrasound. Location and size should be applied in any lesion, that must undergo biopsy.
The density of a mass is related to the expected attenuation of an equal volume of fibroglandular tissue. High density is associated with malignancy.
It is extremely rare for breast cancer to be low density. Here multiple round circumscribed low density masses in the right breast. These were the result of lipofilling, which is transplantation of body fat to the breast. Here a hyperdense mass with an irregular shape and a spiculated margin. Notice the focal skin retraction.
The term architectural distortion is used, when the normal architecture is distorted with no definite mass visible. This includes thin straight lines or spiculations radiating from a point, and focal retraction, distortion or straightening at the edges of the parenchyma.
The differential diagnosis is scar tissue or carcinoma. Architectural distortion can also be seen as an associated feature. For instance if there is a mass that causes architectural distortion, the likelihood of malignancy is greater than in the case of a mass without distortion. Notice the distortion of the normal breast architecture on oblique view yellow circle and magnification view.
A resection was performed and only scar tissue was found in the specimen. Findings that represent unilateral deposits of fibroglandulair tissue not conforming to the definition of a mass. Here an example of global asymmetry. In this patient this is not a normal variant, since there are associated features, that indicate the possibility of malignancy like skin thickening, thickened septa and subtle nipple retraction.
Ultrasound not shown detected multiple small masses that proved to be adenocarcinoma. All types of asymmmetry have different border contours than true masses and also lack the conspicuity of masses.
Asymmetries appear similar to other discrete areas of fibroglandulair tissue except that they are unitaleral, with no mirror-image correlate in the opposite breast. An asymmetry demonstrates concave outward borders and usually is interspersed with fat, whereas a mass demonstrates convex outward borders and appears denser in the center than at the periphery.
The use of the term "density" is confusing, as the term "density" should only be used to describe the x-ray attenuation of a mass compared to an equal volume of fibroglandular tissue. In the atlas calcifications were classified by morphology and distribution either as benign, intermediate concern or high probability of malignancy. In the version the approach has changed. Since calcifications of intermediate concern and of high probability of malignancy all are being treated the same way, which usually means biopsy, it is logic to group them together.
Calcifications are now either typically benign or of suspicious morphology. Within this last group the chances of malignancy are different depending on their morphology BI-RADS 4B or 4C and also depending on their distribution.
There is one exception of the rule: an isolated group of punctuate calcifications that is new, increasing, linear, or segmental in distribution, or adjacent to a known cancer can be assigned as probably benign or suspicious. Read more on breast calcifications. The arrangement of calcifications, the distribution, is at least as important as morphology. These descriptors are arranged according to the risk of malignancy:.
Associated features are things that are seen in association with suspicious findings like masses, asymmetries and calcifications. Associated features play a role in the final assessment. Special cases are findings with features so typical that you do not need to describe them in detail, like for instance an intramammary lymph node or a wart on the skin.
Many descriptors for ultrasound are the same as for mammography. For instance when we describe the shape or margin of a mass. Special cases - cases with a unique diagnosis or pathognomonic ultrasound appearance:. When additional imaging studies are completed, a final assessment is made. Always try to avoid this category by immediately doing additional imaging or retrieving old films before reporting.
Even better to have the old examinations before starting the examination. This patient presented with a mass on the mammogram at screening, which was assigned as BI-RADS 0 needs additional imaging evaluation. Additional ultrasound demonstrated that the mass was caused by an intramammary lymph node. Don't forget to mention in the report that the lymph node on US corresponds with the noncalcified mass on mammography.
In the paragraph on location we will discuss how we can be sure that the lymph node that we found with ultrasound is indeed the same as the mammographic mass.
The breasts are symmetric and no masses, architectural distortion or suspicious calcifications are present. Like BI-RADS 1, this is a normal assessment, but here, the interpreter chooses to describe a benign finding in the mammography report, like:. It is not expected to change over the follow-up interval, but the radiologist would prefer to establish its stability.
Lesions appropriately placed in this category include:. Here a non-palpable sharply defined mass with a group of punctate calcifications. Continue with follow up images. Follow-up at 6, 12 and 24 months showed no change and the final assessment was changed into a Category 2.
Nevertheless the patient and the clinician preferred removal, because the radiologist was not able to present a clear differential diagnosis. At 12 month follow up more than five calcifications were noted in a group. This proved to be DCIS with invasive carcinoma. This category is reserved for findings that do not have the classic appearance of malignancy but are sufficiently suspicious to justify a recommendation for biopsy.
By subdividing Category 4 into 4A, 4B and 4C , it is encouraged that relevant probabilities for malignancy be indicated within this category so the patient and her physician can make an informed decision on the ultimate course of action. This finding is sufficiently suspicious to justify biopsy.
A benign lesion, although unlikely, is a possibility. This could be for instance ectopic glandular tissue within a heterogeneously dense breast. The pathologist could report to you that it is sclerosing adenosis or ductal carcinoma in situ. Both diagnoses are concordant with the mammographic findings.
Highly Suggestive of Malignancy. The current rationale for using category 5 is that if the percutaneous tissue diagnosis is nonmalignant, this automatically should be considered as discordant. Here images of a biopsy proven malignancy. On the initial mammogram a marker is placed in the palpable tumor. Due to the dense fibroglandular tissue the tumor is not well seen.
Ultrasound demonstrated a 37 mm mass with indistinct and angular margins and shadowing. After chemotherapy the tumor is not visible on the mammogram. There may be variability within breast imaging practices, members of a group practice should agree upon a consistent policy for documenting.
When you use more modalities, always make sure, that you are dealing with the same lesion. For instance a lesion found with US does not have to be the same as the mammographic or physical finding. Sometimes repeated mammographic imaging with markers on the lesion found with US can be helpful. Cysts can be aspirated or filled with air after aspiration to make sure that the lesion found on the mammogram is caused by a cyst.
Here images that you've seen before. They are of a patient with a new lesion found at screening. With ultrasound an intramammary lymph node was found, but we weren't sure whether this was the same as the mass on the mammogram. Continue with the mammographic images after contrast injection. Contrast was injected into the node and a repeated mammogram was performed. Here we have proof that the mass is caused by an intramammary lymph node, since the mammographic mass contains the contrast.
This patient presented with a tumor in the left breast.
ACR BI-RADS Atlas® 5th Edition
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