Stereoscopic Digital Mammography, a New 3D Breast Cancer Diagnostic Test, Could Reduce False Positives

A new imaging test may reduce the amount of women recalled for diagnostic tests after a routine mammogram. The results of the study, which were presented on Wednesday at the Radiological Society of North America, says that the new technique, called stereoscopic digital mammography, allows researchers to see the breast tissue in 3D, making diagnosis more accurate as well as detecting breast abnormalities earlier than in standard tests.

"Standard mammography is one of the most difficult radiographic exams to interpret," explained David J. Getty, Ph.D., division scientist at BBN Technologies of Cambridge, Mass and lead author of the study. "In a two-dimensional image of the breast, subtle lesions may be masked by underlying or overlying normal tissue and thus be missed, and normal tissue scattered at different depths can align to mimic a lesion, leading to false-positive detections."

Stereoscopic digital mammography uses two digital x ray images of the breast. Each image is taken from a different vantage point, which an eight degree difference between the two images. The images are then viewed on a stereo display workstation. Viewing the image allows a radiologist to see the internal structure of the breasts in 3D.

"Stereo viewing is the only way to see the structure within the breast volume in true depth," said Dr. Getty.

The study followed 1,093 patients who all had above average risk factors for developing breast cancer. Each patient received a traditional mammogram as well as the stereoscopic digital mammography. Each test was read by a separate radiologist.

The study found 259 instances where second tests were warranted, including those results that required a biopsy. Over one hundred of those cases had true lesions that could develop into breast cancer. Traditional mammograms did not detect 40 out of the 109 lesions found in the study. The stereoscopic digital mammography found all but 24 of the lesions.

"Our early results suggest that stereo digital mammography could contribute to the earlier detection of cancer," Dr. Getty concluded. "A small percentage of the additional lesions missed by standard mammography but detected by stereoscopic mammography will turn out to be cancerous."

The stereoscopic digital mammography was also much better at eliminating false positives. Traditional mammograms caused over one hundred false positives while stereo mammography yielded roughly half the amount.

"In our study, stereo digital mammography reduced false positives by 49 percent," said Dr. Getty. "This could have a significant impact by cutting in half the number of women who are needlessly recalled for additional diagnostic work-ups, resulting in a large savings in cost and patient anxiety."

Source:

Radiological Society of North America, "'Stereo' mammography takes breast imaging to a new dimension", Eurekalert