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10 March 2006 Increasing sensitivity of masses cued on both views by CAD
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Although CAD schemes can detect a high percentage of subtle cancers depicted on "prior" and false-negative cases, radiologists frequently discard most of CAD-cued subtle masses in the clinical environment. As a result of the relatively high false-positive detection rate and the fact that a large number of subtle masses are typically cued only on one view cause radiologists to rely less on (and often ignore) CAD-cued masses. In this study, we present a multi-view based method to increase the number of actual masses that are cued by the CAD scheme on both (ipso-lateral) views and at the same time limiting the overall "case-based" false-positive detection rate. The new scheme includes a traditional single-image based CAD scheme and a multi-view processing module. An image database from 435 examinations (or a total of 1,740 images) consisting 235 examinations depicting a verified malignant mass each and 200 negative examinations was used in this study. The single-image based CAD scheme with a fixed operating threshold (i.e. 0.55) was applied to all images. For each CAD identified region (i.e. with detection score ≥ 0.55), the multi-view processing module defined a matched strip on the corresponding ipso-lateral image and identified all "matched" regions located inside the strip (including those with detection score < 0.55). All matched regions are cued on both views and unmatched regions were discarded. CAD scheme initially detected 172 true masses and 576 false-positive regions. Of the 172 masses, 90 were detected on two views (52%) and 82 were detected only on one view. Of the 576 false-positive detections, only 72 pairs (14%) were considered "matched" and 432 were not, resulting in 504 case-based ("independent") cues. Case-based sensitivity and false-positive rate of the CAD scheme were 73.2% and 1.16 per case. When only matched region pairs were cued, 160 masses (68.1%) and 308 false-positive detections (0.71 per case) were identified on two views. Reducing the original operating threshold from 0.55 to 0.49 resulted in 172 masses and 413 false-positive detections (or 0.95 per case) being cued on two views. By increasing sensitivity through the reduction of the detection threshold only inside the matched strip regions in ipso-lateral images the scheme successfully cued masses on two views by maintaining detection sensitivity while reducing the "case-based" false-positive detection rate.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Bin Zheng, Glen Maitz, Joseph K. Leader, and David Gur "Increasing sensitivity of masses cued on both views by CAD", Proc. SPIE 6144, Medical Imaging 2006: Image Processing, 61441Y (10 March 2006);

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