Computed assisted detection of interval breast cancers

OBJECTIVES: To examine interval cancer detection rate for a system of computer assisted detection (CAD) and its influence on radiologists' sensitivity/specificity in a screen-like retrospective review situation. MATERIALS AND METHODS: Three screening radiologists reviewed previous screen images of 59 interval cancers mixed with other screening mammograms (ratio 1:5) and non-mixed. Mixed interval cases were interpreted both without and with aid of CAD. RESULTS: CAD detected a number of 14 interval cancers while the three radiologists detected 17, 12 and 11 without and 16, 10 and 13 with CAD. Although CAD specificity was low (38%) no reduction in radiologists' specificity occurred using CAD (73%, 82% and 89% without and 78%, 90% and 92% with CAD). Non-mixed reading increased radiologists' detection rate to 21, 17 and 19 interval cancers respectively. CONCLUSION: Despite sufficiently high sensitivity for CAD alone no increase in radiologist sensitivity (or decrease in specificity) occurred with CAD. Improving CAD specificity, with unaffectedly high sensitivity, should make radiologists more inclined to revise interpretations according to CAD. The potential sensitivity increase, noted when using CAD as a double reader, could be realised in this way.