Tomosynthesis Increases Diagnostic Confidence

Tomosynthesis for breast cancer diagnosis has resulted in progressive shifts in the Breast Imaging Reporting and Data System (BI-RADS) final assessment categories and improved diagnostic confidence in biopsy recommendations, according to a study published in Radiology.

Researchers from Yale University School of Medicine in New Haven, CT, performed a retrospective study to evaluate the effect of tomosynthesis in diagnostic mammography on the BI-RADS final assessment categories over time.

The researchers reviewed images from two periods. The first period of 12 months included 2D diagnostic mammography. The second period of three years began after the introduction of tomosynthesis, and was divided into year 1, year 2, and year 3. The rates of BI-RADS final assessment categories 1–5 were compared between the 2D and tomosynthesis groups, and the positive predictive values after biopsy (PPV3) for BI-RADS category 4 and 5 cases were compared.

Masses, architectural distortions, calcifications, and focal asymmetries of lesions were categorized as probably benign (BI-RADS category 3). Lesions for which biopsy was recommended (BI-RADS category 4 or 5) were reviewed.[[{"type":"media","view_mode":"media_crop","fid":"48867","attributes":{"alt":"tomosynthesis","class":"media-image media-image-right","id":"media_crop_5987789617638","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5860","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 114px; width: 171px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":"©zlikovec/Shutterstock.com","typeof":"foaf:Image"}}]]

The results showed that after tomosynthesis was introduced, there was an increase in lesions that were reported as negative or benign (BI-RADS category 1 or 2): 58.7% with 2D mammography versus 75.8% with tomosynthesis at year 3. There was also a reduction in the percentage of probably benign (BI-RADS category 3) final assessments: 33.3% with 2D mammography versus 16.4% with tomosynthesis at year 3.  In addition, although the researchers noted that rates of BI-RADS 4 or 5 assessments did not change significantly with tomosynthesis (8.0% with 2D mammography versus 7.8%with tomosynthesis at year 3, there was a significant increase in the PPV3 (29.6% versus 50%, respectively).

The researchers concluded that over time, using tomosynthesis in the diagnostic setting resulted in a significant increase in cases being classified as normal, accompanied by a continued decrease in the cases categorized as probably benign.