New study questions whether digital mammo takes longer. Image Source: New York Times

Digital mammograms take longer to interpret than film-screen mammograms, according to a study published in the January issue of the American Journal of Roentgenology.

For the study, performed at The University of Texas M.D. Anderson Cancer Center in Houston, four radiologists interpreted 268 digital screening mammograms and 189 film-screening mammograms.

Interpretation times were compared for subgroups of studies based on the interpretation of the study by BI-RADS code, the number of images, the presence or absence of comparison studies and the type of comparison study and whether the radiologist personally selected and hung additional films; the same comparisons were made among individual readers.

The objective was to compare interpretation speeds for digital and film-screen screening mammograms to test whether other variables might affect interpretation times and thus contribute to the apparent difference in interpretation speed between digital mammograms and film-screen mammograms, and to test whether the use of digital rather than film comparison studies might result in significant time savings, according to Tamara Miner Haygood, MD, lead author of the study.

The results showed that for all four readers, mean interpretation times were longer for digital mammograms than for film-screen mammograms, with differences ranging from 76 to 202 seconds. The difference in interpretation speed between digital and film-screen mammograms was independent of other variables.

“Digital mammogram interpretation times were significantly longer than film-screen mammogram interpretation times regardless of whether the digital mammograms were matched with film or digital comparison studies. Exclusive use of digital comparison studies may not cause interpretation times to drop enough to approach the interpretation time required for film-screen mammograms,” the investigators concluded.

"As a result of this study, radiologists should be able to make a more informed choice about whether digital or film-screen mammograms are right for their practice, and if they choose digital screening mammograms, they will have a better idea of how much time to allow for reading them," said Haygood.