No winners-or losers-were declared when the results of mammography CAD performance tests were announced at the RSNA meeting.

Dr. Michael T. Nelson, an associate professor of radiology at the University of Minnesota, found the CADx Second Look, iCAD MammoReader, and R2 Technology Image Checker equally good at identifying breast cancer. The three software programs found 88% to 90% of cancerous breast masses and picked out 98% to 99% of microcalcifications in 128 confirmed cases.

The CAD products were compared using two-view sets of digitized screen-film mammograms, drawn from a base of more than 3000 breast exams performed at the university. The cancers were evenly divided between masses and calcifications. Ductal carcinoma in situ, invasive, and lobular masses were included.

The R2 ImageChecker accurately marked the presence of cancer in at lease one of the two views in 109 of 120 cases, for a sensitivity rate of 90.8%. The iCAD MammoReader missed 12 cases, yielding a sensitivity rate of 90%, and the CADX Second Look found cancers in 107, for a sensitivity rate of 89.2%.

In assessing the products' ability to mark the location of cancer in both views, Nelson found that the iCAD software marked 201 of 248 targets, for 81% sensitivity, the R2 system found 200, for 80.6% sensitivity, and the CADX indicated 180, for 72.6% sensitivity. Two-view accuracy is important, he said, because radiologists tend to dismiss CAD hits in a single view as false positives.

The ImageChecker, MammoReader, and Second Look made an average of 1.22, 1.23, and 1.25 marks per film, respectively.

The results persuaded Nelson that radiologists would benefit from the second reading generated by CAD.

"We think it can pick up on between 17% and 22% more breast cancers with CAD," he said.