Trial finds digital mammography performs better than film

Digital mammography is more accurate than film for diagnosis of breast cancer in women with dense breasts, according to results from the Digital Mammographic Imaging Screening Trial presented at the RSNA meeting.

Dr. Etta Pisano, a professor of radiology at the University of North Carolina, and colleagues, reviewed film and digital mammograms from the DMIST cancer cases and assessed factors contributing to lesion visibility on both modalities. The trial involved 49,529 women from 33 centers.

The researchers sought to understand why digital performed better than film in their analysis of the trial. They found that radiologist readers most frequently attributed differences in cancer visibility to variations in image contrast and not to differences in positioning or compression. Digital showed image contrast much better than film, Pisano said.

Lesion visibility on digital versus film was significantly greater for women with dense breasts even when adjusted for age, lesion type, and mammography system, she said.

For fatty breasts, the researchers found digital and film to be equivalent, with a nonsignificant trend demonstrating film as better in women older than 65. Even with the trend, Pisano does not recommend film screening for women with fatty breasts.

"We have a trend, and frankly given the results of this study, image processing was likely involved in any results that we got. I think the manufacturer should work hard on improving image processing with fatty breasts," she said.

Cancer became more visible on the GE system compared with the Fischer and Fuji products tested, according to the researchers.

Given the accuracy of digital, there is no reason to maintain a film system, Pisano said.