What is Breast Tomosynthesis and 3D Mammography?

Breast Tomosynthesis is better known by most patients and physicians as 3D mammography. However, the use of the term “3D” is a bit misleading. There are no 3D glasses to wear as one would typically expect when viewing a 3D image or movie and nothing “pops” out of the screen in the traditional “stereoscopic” sense.* The images actually appear as “flat” 2D images but are taken at multiple angles relative to the breast and then synthesized to appear as numerous thin traditional 2D images of the breast. This enables the radiologist to look at a single picture for essentially every millimeter of thickness through the breast. Depending on how thick the breast is when compressed, there can be 70 or more images for each view of each breast. In total, there can be 300 or more images created for each mammogram. The term 3D was initially introduced for the purpose of marketing directly to the consumer and to a lesser extent the medical community, but has since become so entrenched in our vocabulary that it’s here to stay.

Ryan Polselli
2D mammogram and 3D mammogram from same patient. The 3D mammogram on the left shows the breast cancer more clearly.

A useful way to understand the concept is to imagine superimposing all the individual tomosynthesis images.  The resulting image would be very similar to the traditional 2D digital mammogram that has been the mainstream of mammographic screening for the last 10 years or so. The advantage of separating the images with tomosynthesis is that it allows the breast imaging radiologist to “see through” the normal breast tissue which can traditionally “overlap.” The image above is a good example. This traditional “overlap” causes 2 main problems. It can hide underlying cancer and it can occasionally overlap in such a way to look suspicious for cancer when there is actually no cancer present. These two problems with the traditional 2D mammogram result in decreased cancer detection rates and more patient recalls for additional imaging to look for cancer that is not there. In other words, 3D mammograms (breast tomosynthesis) detect more breast cancers and results in less false alarms.

Numerous scientific studies have now demonstrated the benefits of 3D mammogram. Among them, a study published in the Journal of the American Medical Association (JAMA) in 2012 involving nearly half a million women demonstrated a significant increase in the breast cancer detection rate and the simultaneous decrease in the recall rate with breast tomosynthesis when compared to standard 2-D digital mammography.

In January of 2015, Medicare was the first insurer to begin reimbursing for breast tomosynthesis. More recently, in August of 2016, Cigna, inspired by the mammogram recommendations of the National Comprehensive Cancer Network (NCCN), became the first private insurer to begin reimbursing for breast tomosynthsis.  More recently, as of April 2017, Anthem and UnitedHealthcare have also reported that they will reimburse for 3D mammogram. Largely as a result of recent studies documenting cost saving and increased breast cancer detection rates, several states including New York, Texas, New Jersey, New Hampshire, and Maryland have introduced bills seeking mandated insurance reimbursement for patients seeking to undergo breast tomosynthesis in their states.  In the future, as the technology becomes more widespread, there will likely be an increasingly larger network of insurance companies that reimburse for breast tomosynthesis.

From the patient perspective, there is nothing noticeably different from having a 3D mammogram when compared with the 2D mammogram other than the “arm” which takes the mammographic “picture” will rotate slightly when obtaining the exposure. Unfortunately compression is still required and the experience is still uncomfortable. Patients that are pre-menopausal can minimize any discomfort by obtaining a mammogram approximately 1 week after a period or if medically appropriate, taking an anti-inflammatory before the procedure.

Ryan Polselli, M.D., Diplomate of the American Board of Radiology, Breast Imaging Radiologist

Please note, this is for informational purposes only and is not intended to be medical advice.

*Note, Fujifilm does market a traditional stereoscopic 3-D viewer, but the technology has not yet been adopted into mainstream clinical practice.

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