The study involved four radiologists who interpreted 268 digital screening mammograms and 189 film-screening mammograms.

"The average interpretation time for all of our readers was 240 seconds -- 4 minutes -- for digital screening mammograms and 127 seconds -- 2 minutes, 7 seconds -- for film-screen screening mammograms," lead author Dr. Tamara Miner Haygood said in a statement. "The digital screening mammograms took nearly twice as long to interpret as the film-screen screening mammograms."

The study identified factors that might have contributed to the time difference.

"Those factors were the identity of the interpreting radiologist, whether there were older studies available for comparison, whether the radiologist looked for and hung up additional films, how many images were obtained and whether the study was normal or not," Haygood said. "In each of these situations, the digital images took longer to interpret than the film-screen images."

The findings are published in the American Journal of Roentgenology.