Digital breast tomosynthesis (DBT) in conjunction with full-field digital mammography (FFDM) has been shown to improve cancer detection, but performing both exams means additional radiation exposure for the patient. Researchers at Christiana Care Health System developed a DBT technique that may eliminate the need for FFDM.

The s2D mammography technique uses breast tomosynthesis images to create a synthesized 2-D compilation image, effectively collapsing down to a 2-D image, which is similar to the one that would be generated by mammography.

"The reason this is potentially practice-changing is that the replacement with an s2D image has a significant radiation dose reduction and decreased time of breast compression," Dr. Jacqueline S. Holt, director of breast imaging at the health system, told HCB News.

Holt and her team studied 78,810 screening mammograms performed from 2011 to 2016. In the study group, 32,076 were screened with mammography, 30,561 with tomosynthesis and mammo, and 16,173 with the s2D synthesizing technique..

They took note of the recall rate, cancer detection rate and the positive predictive value, which is the ability to predict whether an image-detected abnormality is malignant.

The results showed that the s2D recall rate was 4.3 percent compared to 5.8 percent for tomosynthesis with mammo. Using s2D, they detected 76.5 percent of invasive cancers, whereas tomo with mammo detected 61.3 percent.

The false positive rate was also significantly lower, at 3.6 percent for s2D compared to 5.2 percent for tomo with mammo, while the positive predictive value improved by about 12 percent.

"In our large clinical setting, s2D actually outperformed the FFDM image when both were combined with tomosynthesis," said Holt. "[It was] a surprise to us, but the large number of mammograms [used] makes this a statistically powerful study."

Although DBT-s2D holds promise, the images that the technique generates look different than conventional mammography images — and this may impact its utilization.

"I think that radiologists have been reluctant to adopt the technology, and this is exactly why our study is important," said Holt.

She recommends that breast imaging clinics gradually implement the technology and have the radiologists undergo an initial trial period in which the DBT-s2D technique is used side-by-side with DBT-FFDM.

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