3D Mammography: Advances in Breast Cancer Screening

An improved mammography system currently in clinical trials at Emory University’s Breast Imaging Center in Atlanta is showing dramatic improvements in both early detection of suspicious lesions and reductions in false-positive readings. The system, called Stereoscopic Digital Mammography (SDM), reduces false-negative results by 40% and false-positive findings by 49%, compared to standard two-dimensional mammography. The ongoing clinical trial at Emory has involved 1,093 women who received both a standard digital mammogram and a stereoscopic digital mammogram. The combined mammography procedures have detected a total of 259 suspicious findings, which were referred for additional diagnostic testing, including biopsy when indicated. Of those, 109 were determined to be true lesions. Standard mammography missed 40 of the 109 lesions, whereas the stereoscopic exam missed 24. Of the 259 fi ndings, 150 were false-positives upon further testing. Standard mammography produced 103 false positives, compared with just 53 with stereo mammography.

Principal investigator David Getty, MD, division scientist at BBN Technologies, presented the trial results at the Radiological Society of North America (RSNA) conference in Chicago on November 27, 2007. Dr. Getty, a prominent researcher in the fi eld of medical imaging, conducted the preliminary study of SDM with Carl D’Orsi, MD, the director of Breast Imaging at Emory’s Winship Cancer Institute and primary clinical investigator of the SDM trial.

The SDM system provides a three-dimensional, in-depth image of the breast. The results of the Emory University trial indicate that the system enables radiologists to detect subtle lesions that they often miss when using standard digital mammography. In standard mammography, subtle lesions in the breast may be masked by overlying or underlying normal tissue, leading to missed detection, and layers of tissue may superimpose to resemble a lesion, leading to a false-positive report.

Stereoscopic mammography overcomes these challenges by providing a view that separates tissue in depth, making subtle lesions more visible and their characteristics far clearer. Dr. Getty explains, “In the current standard mammography exam, two images of the breast are taken from two diff erent viewpoints. The radiologist must examine the two images individually and then infer from the two images how the tissue is arranged in the breast volume. With the new stereo mammography technology, a stereo pair of images is taken and then displayed on the new stereoscopic display workstation. The resulting three-dimensional image enables the radiologist to see directly how the tissue is distributed in depth in the breast.”

According to Dr. Getty, the benefi ts of the SDM system include earlier detection, reduced costs, and less unnecessary anxiety. In addition, offering wide-scale SDM would entail only minor changes to digital mammography equipment and software. “We believe that the added information provided with the SDM system will result in less frequent recall of women for further work-up, reducing the emotional trauma, uncertainty, and financial costs associated with unnecessary additional diagnostic work and procedures,” said Dr. Getty. Additionally, researchers believe the SDM imaging technique could be used to help detect other types of soft tissue lesions, such as those associated with lung or prostate cancer. “There are enormous possibilities,” Getty said.

Joyce Kuzmin is the Communications Director at BBN Technologies.