A self-tuned graph-based framework for localization and grading prostate cancer lesions: An initial evaluation based on multiparametric magnetic resonance imaging

Multiparametric magnetic resonance imaging (mpMRI) has been established as the state-of-the-art examination for the detection and localization of prostate cancer lesions. Prostate Imaging-Reporting and Data System (PI-RADS) has been established as a scheme to standardize the reporting of mpMRI findings. Although lesion delineation and PI-RADS ratings could be performed manually, human delineation and ratings are subjective and time-consuming. In this article, we developed and validated a self-tuned graph-based model for PI-RADS rating prediction. 34 features were obtained at the pixel level from T2-weighted (T2W), apparent diffusion coefficient (ADC) and dynamic contrast enhanced (DCE) images, from which PI-RADS scores were predicted. Two major innovations were involved in this self-tuned graph-based model. First, graph-based approaches are sensitive to the choice of the edge weight. The proposed model tuned the edge weights automatically based on the structure of the data, thereby obviating empirical edge weight selection. Second, the feature weights were tuned automatically to give heavier weights to features important for PI-RADS rating estimation. The proposed framework was evaluated for its lesion localization performance in mpMRI datasets of 12 patients. In the evaluation, the PI-RADS score distribution map generated by the algorithm and from the observers' ratings were binarized by thresholds of 3 and 4. The sensitivity, specificity and accuracy obtained in these two threshold settings ranged from 65 to 77%, 86 to 93% and 85 to 88% respectively, which are comparable to results obtained in previous studies in which non-clinical T2 maps were available. The proposed algorithm took 10s to estimate the PI-RADS score distribution in an axial image. The efficiency achievable suggests that this technique can be developed into a prostate MR analysis system suitable for clinical use after a thorough validation involving more patients.

Computers in biology and medicine. 2018 Apr 03 [Epub ahead of print]

Weifu Chen, Mingquan Lin, Eli Gibson, Matthew Bastian-Jordan, Derek W Cool, Zahra Kassam, Huageng Liang, Guocan Feng, Aaron D Ward, Bernard Chiu

School of Mathematics, Sun Yat-sen University, Guangzhou, China; Department of Electronic Engineering, City University of Hong Kong, Hong Kong, China., Department of Electronic Engineering, City University of Hong Kong, Hong Kong, China., Biomedical Engineering, University of Western Ontario, London, Ontario, Canada., Department of Medical Imaging, University of Western Ontario, London, Ontario, Canada., Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China., School of Mathematics, Sun Yat-sen University, Guangzhou, China., Lawson Health Research Institute, London, Ontario, Canada., Department of Electronic Engineering, City University of Hong Kong, Hong Kong, China. Electronic address: .