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Confused about BI-RADS 0? Here are guidelines to help you along


Reference to need for additional imaging in both category 0 and category 3 definitions can confuse patients and providers

Is there confusion surrounding the Breast Imaging Reporting and Database System (BI-RADS) category 0 assessment? If it is used in the manner in which the American College of Radiology originally meant it to be implemented, there shouldn't be. The only time BI-RADS category 0 should be used is when a screening mammogram is read and the final assessment is "incomplete-needs further imaging studies" or "needs comparison to prior studies."

BI-RADS was designed by the ACR in 1993 to provide an organized approach to image interpretation and reporting. Part of the organization's goal was to standardize reporting and reduce the confusion in breast imaging interpretations. BI-RADS not only aids radiologists in managing the medical outcomes audit but is also an excellent information tool to help referring physicians appropriately manage and follow their patients' mammography studies.1

To clarify when and how category 0 should be assessed, it is important to know the exact wording that is used by BI-RADS for each category:

• Category 0—need additional imaging evaluation and/or prior mammograms for comparison;

• Category 1—negative;

• Category 2—benign finding(s);

• Category 3—probably benign finding; initial short-interval follow-up suggested;

• Category 4—suspicious abnormality; biopsy should be considered;

• Category 5—highly suggestive of malignancy; appropriate action should be taken; and

• Category 6—known biopsy; proven malignancy, appropriate action should be taken.

A cloud of confusion seems to surround the use of category 0 as opposed to category 3, as both reference additional imaging. The difference is that category 0 is applied when critical information needed to make the final assessment is missing,2 and category 3 is assigned when a benign finding (with a less than 2% chance of malignancy) is seen on the mammogram but stability needs to be established.3 The ACR suggests that it is inadvisable to render a category 3 assessment when interpreting a screening mammogram (Figure 1).


The guidelines may not seem confusing, but in reality they can often lead us into a gray, somewhat controversial area. A screening patient has a smoothly outlined, probably benign mass noted on prior images, for example. The last report was given a category 2 (benign) finding. You might be tempted to give a BI-RADS category 3 assessment to check the mass's stability after several months. If a workup was not previously performed, one should be done immediately. But this workup, a request for additional evaluation, is considered a recall and would be given a BI-RADS category 0 assessment. So when is category 3 used? At the time of recall, after a workup has been done on the screening mammogram, if you feel that the questionable area is benign. Short-term follow-up will confirm the stability of benign findings. This is the proper use of a category 3 BI-RADS assessment.

Using the BI-RADS category 0 assessment spurs a commitment from the referring physician, the radiologist, and the radiology staff to either notify the patient that she needs to schedule a further workup or retrieve prior studies for comparison. It is crucial that the patient with an incomplete exam not get lost in the system.

A system of checks and balances must be put into place. This could include software programs and plenty of staff time. Not all facilities have the staff or finances to support such a system, however. For example, when prior films are requested, some facilities charge a fee for handling and mailing the films. Many calls—sometimes long distance—are often necessary to track down studies. Additional staff or overtime expenses may also be required to achieve this goal. A smaller clinic or radiology office may not be able to absorb these additional expenses.

At the Elizabeth Wende Breast Care (EWBC), we have a unique workflow environment. An average of 250 screening mammography patients are seen daily. The majority of these patients get their mammogram results and have a full workup done, if necessary, onsite during the same appointment. Each patient has the option to either stay for results of the screening mammogram or leave and have the results sent in the mail. Only about 30% of patients choose to leave, knowing that they have a 20% chance of being recalled for additional imaging (BI-RADS category 0).

Within the last 10 years, we have noted that fewer patients choose to stay. In the past, 98% of the patients stayed for their results. Now, as more women are working full time and have multiple tasks in and out of the home, they find they have less time to spend at the doctor's office. Therefore, more and more women choose to leave without their results or choose appointment times when same-day results are not available. We cater to women's working schedules with early and late screening appointments. We also open up screening without results on Saturdays. This creates an ongoing stream of new patients and promotes screening for women who can't get to an appointment during the week. It also creates more category 0 assessments.

Our protocol at EWBC regarding BI-RADS category 0 for further imaging studies is as follows:

1. The report is dictated to the referring physician stating the need for further workup;

2. A similar letter, but in lay terms, is mailed to the patient (per Mammography Quality Standards Act of 1997 guidelines4) requesting that she call our office to make a follow-up appointment; and

3. A staff member calls the patient at home or work to schedule an appointment as a proactive measure to ensure compliance.

If the appointment is not made within four weeks and we have not been able to get in touch with her, a certified letter is sent to the patient requesting that she contact the office and schedule an appointment to complete her study. This way, we have documentation that the patient has received the notice, as she has to sign for her certified letter. Another letter is also sent to her referring physician.


This protocol requires a huge time commitment for the staff and the radiologist to police the nonconforming patient. Fortunately, very few of our recalled patients do not conform to recall; only about 3% are hesitant to comply. The majority of patients cooperate with the request for workup, with compliance at approximately 97%. In our facility, the targeted wait time to get the patient back for additional workup is two to four weeks, but the actual time varies depending on doctor availability.

The letter also gives the patient the opportunity to consider a second opinion at another facility if she does not wish to return to us or lives too far away to return easily. Sometimes a patient has a bad experience in the doctor's office, even if she does not complain. You may be unaware of the problem, but the patient may refuse to return if requested. At the time of the letter notification, she can request that her films and reports be sent to a facility of her choice.

We have patients who travel quite a distance to come to our facility, and travel may be difficult, particularly in the winter. Because of the weather, travel limitations, and other health concerns, some women from surrounding areas may wait to return for their workup. We have a paper trail to keep track of these patients, and they get called several times. When the appointment for the follow-up is made, the staff checks and double-checks that the patient actually comes through the door.


The most common reason for the BI-RADS category 0 assessment at our office is the need for additional imaging; 80% of the time the reason for the recall is a questionable mass that most likely is caused by overlapped tissue (Figure 2). If the questionable mass proves to be overlapped tissue after additional views (usually one or two additional views are needed), then no further workup is necessary.

Calcifications are the next most likely reason for a recall (Figure 3), followed by recall for technical reasons, such as motion on the image. In 2006, 1937 of our patients were given category 0 assessments and needed to return for further imaging studies; 42 cancers were found in this group (Figure 4).

When additional radiographic imaging does not give the radiologist the information necessary for diagnosis, ultrasound and biopsy may be the next tools needed. Once workup is complete, the proper BI-RADS category is assessed.

If prior studies are needed for diagnosis but are not available at the time of the mammogram interpretation, BI-RADS category 0 should be assessed. A study by Orel et al found this to be the most frequent reason for assigning a category 0 assessment.5 In our facility, the medical records department will call and request studies from other local facilities, making every effort to get the previous studies prior to the patient's office visit, but sometimes we fail in that effort, (the average wait time for films is two weeks). A courier picks up or drops off the films, or they are placed in the mail. This is time-consuming and expensive, but necessary.

The prior studies may show that additional imaging studies are still necessary. If the priors do not arrive in time for the patient's visit, the patient's chart will be flagged with a large "AWAITING" note stapled to it. The patient will proceed with the office visit and the dictation on the report will state: BI-RADS category 0 assessment, awaiting prior mammograms for comparison. The "awaiting" note will direct the chart back to the medical records department. When the films arrive, the chart will be brought back to the radiologist and the studies read with the outside priors. An addendum will be dictated and a final BI-RADS assessment can be made.


Using the BI-RADS categories should ultimately assist radiologists in standardizing reporting. The BI-RADS system can become confusing, as it is applied differently to each facility's unique work environment.

The radiologist who signs the report is ultimately responsible for supervising his or her staff and for following through on recommendations of the BI-RADS category that was assessed. In addition, the use of BI-RADS assessments can aid referring physicians as they follow their patients' breast care.


1. Eberl M, Fox C, Edge S, et al. BI-RADS classifications for management of abnormal mammograms. J Am Board Fam Med 2006;19(2):161-164.

2. American College of Radiology (ACR). BI-RADS-Mammography. In: ACR breast imaging reporting and data system, breast imaging atlas, 4th ed. Reston, VA: American College of Radiology; 2003:194.

3. American College of Radiology (ACR). BI-RADS-Mammography. In: ACR breast imaging reporting and data system, breast imaging atlas, 4th ed. Reston, VA: American College of Radiology; 2003:195.

4. MQSA Final Rule 62(208):55988.

5. Orel SG, Kay N, Reynolds C, Sullivan DC. BI-RADS categorization as a predictor of malignancy. Radiology 1999;211(3):845-850.Acknowledgement

The author would like to thank research staff members Val Andolina and Renee Morgan for their help in the preparation of this article. Both are radiology technologists specializing in mammography.

Dr. Destounis is a diagnostic radiologist at Elizabeth Wende Breast Care, LLC, in Rochester, NY, and a clinical associate professor of radiology at the University of Rochester School of Medicine and Dentistry.

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