Automated detection of aggressive prostate cancer on Magnetic Resonance Imaging (MRI) can help guide targeted biopsies and reduce unnecessary invasive biopsies. However, automated methods of prostate cancer detection often have a sensitivity-specificity trade-off (high sensitivity with low specificity or vice-versa), making them unsuitable for clinical use. Here, we study the utility of integrating prior information about the zonal distribution of prostate cancers with a radiology-pathology fusion model in reliably identifying aggressive and indolent prostate cancers on MRI. Our approach has two steps: 1) training a radiology-pathology fusion model that learns pathomic MRI biomarkers (MRI features correlated with pathology features) and uses them to selectively identify aggressive and indolent cancers, and 2) post-processing the predictions using zonal priors in a novel optimized Bayes’ decision framework. We compare this approach with other approaches that incorporate zonal priors during training. We use a cohort of 74 radical prostatectomy patients as our training set, and two cohorts of 30 radical prostatectomy patients and 53 biopsy patients as our test sets. Our rad-path-zonal fusion-approach achieves cancer lesion-level sensitivities of 0.77±0.29 and 0.79±0.38, and specificities of 0.79±0.23 and 0.62±0.27 on the two test sets respectively, compared to baseline sensitivities of 0.91±0.27 and 0.94±0.21 and specificities of 0.39±0.33 and 0.14±0.19, verifying its utility in achieving balance between sensitivity and specificity of lesion detection.
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