Digital mammography is more accurate only for certain groups of women
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《英国医生杂志》
Digital mammography was significantly better than conventional film mammography at detecting breast cancer in young women, premenopausal and perimenopausal women, and women with dense breasts. These results are from a study of 49 528 asymptomatic women at 33 sites in the United States and Canada and were published online on 16 September 2005 in the New England Journal of Medicine (www.nejm.com, doi:10.1056/NEJMoa052911).
Results of the trial, conducted by the American College of Radiology Imaging Network over two years, were released on the internet last week to coincide with a presentation of the data at a meeting of the network in Arlington, Virginia.
The authors warned that the higher cost of digital mammography is likely to slow its adoption: "Digital systems currently cost approximately 1.5 to 4 times as much as film systems."
All relevant information was available for 42 760 of the women in the trial and their mammograms were independently interpreted by two radiologists. Breast cancer status was ascertained on the basis of a breast biopsy done within 15 months or a follow-up mammogram obtained at least 10 months after entering the study.
Digital mammograms, like the ones above being examined by Dr George Adams at the Anne Arundel Medical Center, Maryland, currently cost approximately 1.5 to 4 times as much as film systems
Credit: AAMC
In the entire population, the diagnostic accuracy of digital and film mammography was similar (difference between methods in the area under the receiver operating curve 0.03, 95% confidence interval -0.02 to 0.08; P=0.18). But the accuracy of digital mammography was significantly higher than that of film mammography in women younger than 50 (0.15, 0.05 to 0.25; P=0.002), women with heterogeneously dense or extremely dense breasts (0.11, 0.04 to 0.18; P=0.003), and premenopausal or perimenopausal women (0.15, 0.05 to 0.24; P=0.002).
The authors say that digital mammography also offers other advantages over film mammography, including easier access to images and computer aided diagnosis; improved means of transmission, retrieval, and storage of images; and use of a lower average dose of radiation without a compromise in diagnostic accuracy.
"In a digital image, the x ray transmission can be manipulated to enhance visualisation of subtle structural changes in tissue over the entire breast. For mammograms, the most problematic areas are those in which cancers can be hidden by adjacent dense tissue owing to small differences in contrast between lesions and the fibroglandular background. The visibility of a subtle mass or cluster of calcifications present in the image can be increased if the image contrast is adjusted."(David Spurgeon)
Results of the trial, conducted by the American College of Radiology Imaging Network over two years, were released on the internet last week to coincide with a presentation of the data at a meeting of the network in Arlington, Virginia.
The authors warned that the higher cost of digital mammography is likely to slow its adoption: "Digital systems currently cost approximately 1.5 to 4 times as much as film systems."
All relevant information was available for 42 760 of the women in the trial and their mammograms were independently interpreted by two radiologists. Breast cancer status was ascertained on the basis of a breast biopsy done within 15 months or a follow-up mammogram obtained at least 10 months after entering the study.
Digital mammograms, like the ones above being examined by Dr George Adams at the Anne Arundel Medical Center, Maryland, currently cost approximately 1.5 to 4 times as much as film systems
Credit: AAMC
In the entire population, the diagnostic accuracy of digital and film mammography was similar (difference between methods in the area under the receiver operating curve 0.03, 95% confidence interval -0.02 to 0.08; P=0.18). But the accuracy of digital mammography was significantly higher than that of film mammography in women younger than 50 (0.15, 0.05 to 0.25; P=0.002), women with heterogeneously dense or extremely dense breasts (0.11, 0.04 to 0.18; P=0.003), and premenopausal or perimenopausal women (0.15, 0.05 to 0.24; P=0.002).
The authors say that digital mammography also offers other advantages over film mammography, including easier access to images and computer aided diagnosis; improved means of transmission, retrieval, and storage of images; and use of a lower average dose of radiation without a compromise in diagnostic accuracy.
"In a digital image, the x ray transmission can be manipulated to enhance visualisation of subtle structural changes in tissue over the entire breast. For mammograms, the most problematic areas are those in which cancers can be hidden by adjacent dense tissue owing to small differences in contrast between lesions and the fibroglandular background. The visibility of a subtle mass or cluster of calcifications present in the image can be increased if the image contrast is adjusted."(David Spurgeon)