A new diagnostic technique, stereoscopic mammogram, that is capable of producing 3-dimensional views of the breast could reduce the number of women recalled for additional testing following routine mammograms.
"Standard mammography is one of the most difficult radiographic exams to interpret," said David J. Getty, Ph.D., division scientist at BBN Technologies of Cambridge, Mass. "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."
The procedure consists of two digital x-rays of the breast from two different points of view. When both images are viewed on a stereo display workstation the radiologist can see the breast in 3-D.
"Stereo viewing is the only way to see the structure within the breast volume in true depth," said Dr. Getty, who has been working on the development of the technology over the past 12 years.
As of July 2007, 1,093 patients at elevated risk for developing breast cancer were enrolled in the trial. Each patient received a full-field, standard digital mammography screening examination and a full-field, stereoscopic digital exam, which were then read independently by different radiologists.
A total of 259 suspicious findings were detected by the combined mammography procedures and 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 while the stereoscopic exam failed to detect 24.
"Our early results suggest that stereo digital mammography could contribute to the earlier detection of cancer," Dr. Getty said. "A small percentage of the additional lesions missed by standard mammography but detected by tereoscopic mammography will turn out to be cancerous."
Of the 259 findings, 150 were false positives, meaning further testing revealed that no abnormality was present. Standard mammography yielded 103 false positives; stereo mammography yielded 53.
"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: PRNewsWire]
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