Stereoscopic digital mammography reduces recall rates

Stereoscopic digital mammography significantly reduces recall rates compared with conventional two-dimensional digital mammography, according to a study published online Nov. 13 in the journal Radiology.

According to the researchers, led by Carl J. D'Orsi, M.D., of the department of imaging radiology and imaging sciences at Emory University in Atlanta, 2-D digital mammography, while currently the primary screening method for early detection of breast cancer, can't provide information about the volumetric appearance of a detected lesion. Stereoscopic digital mammography can rectify this.

The stereoscopic digital mammography technique involves modifying digital mammography equipment to allow the X-ray tube to move separately from the cassette, and then viewing the resulting images on two monitors placed one above the other.

"Our eyes see the world from two slightly different perspectives," D'Orsi said in an announcement. "In this technique, the X-ray tube functions as the eyeball, with two different images providing slightly different views of the internal structure of the breast."

In the study, D'Orsi and his colleagues compared 2-D digital mammograms to stereoscopic digital mammograms in 779 patients who had an elevated risk of developing breast cancer. The patients underwent both examinations in a single visit, and two radiologists evaluated a total of 1,298 exams. The findings were correlated by biopsy or one-year follow-up.

The researchers found that, compared with conventional digital mammography, stereoscopic digital mammography showed "significantly" higher specificity (91.2 percent versus 87.8 percent) and accuracy (90.9 percent compared to 87.4 percent). The recall rate for stereoscopic digital mammography was 9.6 percent compared to 12.9 percent for conventional digital mammography.

According to D'Orsi, the researchers are expanding their research to study the effects of stereoscopic digital mammography with lower radiation dose, since the dose received for purposes of the study was about twice the standard dose for mammography.

"In this study, we used a high-risk population to get an adequate number of cancers, and we acquired each of the images comprising the stereo pairs with a full standard X-ray dose," D'Orsi said. "Now that we know the technique is worthwhile, we're repeating the study in the general population with a dose comparable to routine screening mammography."

To learn more:
- read the abstract in Radiology
- read the announcement