Computer aided detection (CAD) is a potentially useful adjunct to double reading of screening mammograms, according to a recently released study.

Computer aided detection (CAD) is a potentially useful adjunct to double reading of screening mammograms, according to a recently released study.

The study included 3,683 women who were part of the Oslo I study comparing screen-film mammography and full-field digital mammography. All women had both film and digital mammograms which were then independently interpreted by two radiologists.

"Twenty nine cancers were prospectively diagnosed in the initial screening round," said Per Skaane, MD, of Ullevaal University Hospital in Norway, and lead author of the study.

Double reading of screen-film mammograms resulted in the diagnosis of 27 of 29 cases of cancer. CAD correctly marked 27 cases, of which one was missed at double reading. "Double reading of full-field digital mammograms resulted in the diagnoses of 22 of the 29 cases of cancer," said Dr. Skaane. "The CAD system correctly marked 27 cases and, of importance, marked all seven cancers missed in double reading of the full-field digital mammography cases," he said.

"Twenty six cancers were diagnosed during an interval and subsequent screening round, of which 10 were judged (in retrospect) to be visible and actionable, i.e. they were overlooked in the initial screening," Dr. Skaane said. "CAD correctly marked six of the ten overlooked cancers on the screen film mammograms and all ten of the ten overlooked cancers on full-field digital mammograms," he said.

"In the combined group of 39 cancers (29 diagnosed at baseline and ten subsequently diagnosed 'actionable' cancers), CAD correctly marked five cancers that were overlooked by double reading on screen film mammograms, and 14 cancers overlooked on full-field digital mammograms," said Dr. Skaane. "Double reading found two cancers that were not marked by CAD on either film screen or full-field digital mammograms," he said.

"Our study shows that CAD has the potential to increase the cancer detection rate for women attending a breast cancer screening program that employs independent double reading, whether the imaging modality is screen film mammography or full-field digital mammography. Since CAD has the potential to mark tumors that might be overlooked by radiologists, adding CAD to double reading may mean these cancers could be detected at an earlier stage," Dr. Skaane said.

The study appeared in the February issue of the American Journal of Roentgenology, published by the American Roentgen Ray Society.