Mammography
New Mammo Technique Could Lower False-positives
Dec. 12, 2007
A technique that produces 3-D views of breast tissue could reduce the recall rate for mammography, according to a new study. Researchers said offering the technology on a wider scale would entail only minor changes to digital mammography equipment and software.
Standard 2-D mammograms often are difficult to interpret, as overlying normal tissue can mask subtle lesions and normal tissue scattered at different depths can align to resemble a lesion, leading to false-positive detections.
A new technique known as stereoscopic digital mammography offers the promise of reducing false-positive results. In stereoscopic digital mammography, the mammographer acquires two digital x-ray images of the breast from two different points of view separated by about eight degrees. When radiologists view the images on a stereo display workstation, they can see the internal structure of the breast in three dimensions.
In the ongoing study, researchers looked at 1,093 patients at elevated risk for developing breast cancer. The patients received a full-field, standard digital mammography screening examination and a full-field, stereoscopic digital exam, and different radiologists read the results. The stereoscopic exam relied on a full-field digital mammography unit modified to take stereo pairs of images. The workstation enabled the mammographer to fuse the stereo image pair and to view the breast in depth.
There were a total of 259 suspicious findings on the combined mammography procedures. Patients with suspicious results underwent additional testing, including biopsy when indicated. Of the 259 suspicious findings, 109 turned out to be true lesions. Standard mammography missed 40 of the 109 lesions while the stereoscopic exam missed only 24.
"Our early results suggest that stereo digital mammography could contribute to the earlier detection of cancer," said David J. Getty, Ph.D., division scientist at BBN Technologies of Cambridge, Mass., which helped develop the stereo display workstation used in the trial. "A small percentage of the additional lesions missed by standard mammography but detected by stereoscopic mammography will turn out to be cancerous." Researchers presented the findings in November at the annual meeting of the Radiological Society of North America in Chicago.
Standard mammography resulted in 103 false positives, compared with 53 for stereo mammography.
"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 workups, resulting in a large savings in cost and patient anxiety."
A total of 1,500 women at elevated risk of developing breast cancer will have received both the stereo and standard digital mammography screening exams by the end of the trial in December.
The trial took place at Emory University Breast Clinic in Atlanta.
New Mammo Technique Could Lower False-positives
Dec. 12, 2007
A technique that produces 3-D views of breast tissue could reduce the recall rate for mammography, according to a new study. Researchers said offering the technology on a wider scale would entail only minor changes to digital mammography equipment and software.
Standard 2-D mammograms often are difficult to interpret, as overlying normal tissue can mask subtle lesions and normal tissue scattered at different depths can align to resemble a lesion, leading to false-positive detections.
A new technique known as stereoscopic digital mammography offers the promise of reducing false-positive results. In stereoscopic digital mammography, the mammographer acquires two digital x-ray images of the breast from two different points of view separated by about eight degrees. When radiologists view the images on a stereo display workstation, they can see the internal structure of the breast in three dimensions.
In the ongoing study, researchers looked at 1,093 patients at elevated risk for developing breast cancer. The patients received a full-field, standard digital mammography screening examination and a full-field, stereoscopic digital exam, and different radiologists read the results. The stereoscopic exam relied on a full-field digital mammography unit modified to take stereo pairs of images. The workstation enabled the mammographer to fuse the stereo image pair and to view the breast in depth.
There were a total of 259 suspicious findings on the combined mammography procedures. Patients with suspicious results underwent additional testing, including biopsy when indicated. Of the 259 suspicious findings, 109 turned out to be true lesions. Standard mammography missed 40 of the 109 lesions while the stereoscopic exam missed only 24.
"Our early results suggest that stereo digital mammography could contribute to the earlier detection of cancer," said David J. Getty, Ph.D., division scientist at BBN Technologies of Cambridge, Mass., which helped develop the stereo display workstation used in the trial. "A small percentage of the additional lesions missed by standard mammography but detected by stereoscopic mammography will turn out to be cancerous." Researchers presented the findings in November at the annual meeting of the Radiological Society of North America in Chicago.
Standard mammography resulted in 103 false positives, compared with 53 for stereo mammography.
"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 workups, resulting in a large savings in cost and patient anxiety."
A total of 1,500 women at elevated risk of developing breast cancer will have received both the stereo and standard digital mammography screening exams by the end of the trial in December.
The trial took place at Emory University Breast Clinic in Atlanta.
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