A new technique for detecting breast cancer missed 40% fewer cases of the disease, according to preliminary results of an U.S. test, a group of scientists from Cambridge and Atlanta reports.

Stereoscopic digital mammography, which gives a three-dimensional view if the inner structures of the breast, cuts the number of falsely diagnosed tumors in half, compared with conventional mammography.

"Standard mammography is one of the most difficult radiographic exams to interpret. 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," said Dr. David Getty, division scientist at BBN Technologies of Cambridge, Massachusetts, which is developing the new technology.

Dr. Getty presented the preliminary results at the meeting of the Radiological Society of North America this week. Carl D’Orsi of Emory University Breast Clinic was the co-author of the study.

About 1,093 women at high risk from breast cancer were screened with both stereo and standard digital mammography in the trial conducted at Emory.

Radiologists who read the studies found 259 suspicious finding, the paper said. Of those, 109 were confirmed as cancer by additional tests, including biopsies and 150 false positives. Standard mammography missed 40 cancerous lesions compared to stereo mammography, which missed 24, the authors say.

Conventional mammography produced 103 false positives and stereo mammography had 53. The trial will include 1,500 women when it ends in December.

"Two-dimensional imaging masks subtle lesions. With 3-D mammography, this is greatly reduced. Lesions can be seen as lying at different depths," Getty explained.