June 25, 2024

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Ultrasound examination BI-RADS classification

Ultrasound examination BI-RADS classification



Ultrasound examination BI-RADS classification. How to evaluate category 0, 1, 2, 3, 4, 5.

Ultrasound examination BI-RADS classification



How to evaluate category 0:

  • Category 0: Evaluation is not completed-further imaging evaluation and/or comparison with previous imaging examinations are required
  • In general, diagnostic breast ultrasound examinations should not use Category 0 assessment results. This is because before the patient leaves, a complete diagnostic breast imaging examination (including ultrasound and X-ray examination, if required at the same time) should have been completed. In rare cases, if the diagnostic breast ultrasound examination cannot be completed due to imaging equipment or personnel problems, or because the patient decides to leave before completing the examination process, it should be assessed as BI-RADS 0.

Category 0 cannot be used for diagnostic breast imaging when further MRI is required. Instead, the reading doctor should issue a final evaluation report before the MRI examination.


However, for screening breast ultrasound examinations, a category 0 assessment result is appropriate, as only a small number of standard ultrasound images are usually available for screening.



How to evaluate category 1

  • Category 1: Negative
  • Describe normal inspection results.
  • Personal opinion: Ultrasound should not issue a diagnosis of “breast lobular hyperplasia”, but should be assessed as “BI-RADS Category 1”. In the ultrasound BI-RADS, there is no description of “breast lobular hyperplasia”.



How to evaluate category 2

  • Category 2: benign
  • One or more simple cysts, lymph nodes in the breast, postoperative effusion, breast implants, or complex cysts/possible fibroadenomas that have not changed for at least 2 or 3 years.
  • The reader may choose not to describe the above findings, at which time the examination is evaluated as negative (BI-RADS category 1).
  • Multiple breasts on both sides (the total number of lumps is at least 3, and each breast has at least 1) most solid masses with smooth edges, as long as all the masses are similar in appearance, ultrasound can be evaluated as benign (Class 2) .
  • Treatment suggestion: Routine screening appropriate to age. An example of inconsistent BI-RADS assessment classification and treatment recommendations is simple breast cysts, which belong to BI-RADS category 2, but in order to control pain, cystic fluid aspiration is required.



How to evaluate 3 categories

Category 3: probably benign

There is currently evidence to support the assessment of the following 3 conditions into 3 categories (malignant possibility ≤ 2%):

  • ① Solid masses with smooth edges, oval, parallel growth (most likely fibroadenoma) (supported by strong evidence); however, for clinically palpable solid masses with edges smooth, the literature only Strong support for women younger than 40 years old may be benign, this type of women constitutes the vast majority of the study cases.
  • ② Single complex cyst (supported by strong evidence);
  • ③ Small clusters of cysts (the authority of supporting data is not yet sufficient because only a small number of samples are included).


 There is no evidence yet, but according to expert opinions, the following 3 situations can be assessed into 3 categories:

  • ①Hyperechoic mass, with hypoechoic to non-echoic components in the center, and edema around it, which is consistent with fat necrosis;
  • ②Refraction sound and shadow produced on the edge of fat lobules;
  • ③ It is believed to be the structural distortion caused by the postoperative scar.

In addition to the above, only if the ultrasound doctor has personal experience to justify the watchful-waiting approach, it is best to observe a sufficient number of ultrasound examination cases to indicate that the malignancy may be within the limit of ≤2% Only BI-RADS category 3 can be used.


Treatment recommendations:

follow up for 6 months-6 months-1 year; after 2-3 years of follow-up, if the lesion remains stable, it is classified as BI-RADS category 2. If the diameter increases by more than 20% within 6 months, or other suspicious changes occur, the assessment should be immediately upgraded to suspicious (BI-RADS category 4).



How to evaluate 4 categories

  • Category 4 (category 4): suspicious
  • Such lesions do not have typical malignant manifestations, but are suspicious enough to warrant a biopsy.
    Descriptive words that prove a benign evaluation result are edge smoothing, ellipse (including the term large leaf), and parallel position. If any other descriptors classified by these 3 groups of features (ie, edge, shape, and parallelism) are suitable for the mass, such as blurred edges, irregular shapes, or non-parallel positions, the mass should be assessed as suspicious.
  • How to evaluate the 4 sub-categories, BI-RADS did not provide corresponding information.
  • (Commentary by Zhang Huabin: I personally use this rule in clinical practice. Only one suspicious sign is classified as 4A, two suspicious signs are classified as 4B, and three or more suspicious signs are classified as 4C or 5. It is only a personal habit, not Supported by evidence-based medicine.)



How to evaluate 5 categories

  • Category 5: High suggestive of malignancy
  • Such lesions have a high risk of malignancy (≥95%), and biopsy should be performed when there are no clinical contraindications.
  • How to evaluate the 5 categories, BI-RADS did not provide corresponding information.




Ultrasound examination BI-RADS classification

(source:internet, reference only)

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