Novel Radiomic Analysis on Bi-Parametric MRI for Characterizing Differences Between MR Non-Visible and Visible Clinically Significant Prostate Cancer.

Background: around one third of clinically significant prostate cancer (CsPCa) foci are reported to be MRI non-visible (MRI-). Objective: To quantify the differences between MR visible (MRI+) and MRI- CsPCa using intra-and peri-lesional radiomic features on bi-parametric MRI (bpMRI).Methods: This retrospective and multi-institutional study comprised 164 patients with pre-biopsy 3T prostate multi-parametric MRI from 2014 to 2017. The MRI- CsPCa referred to lesions with PI-RADS v2 score < 3 but ISUP grade group > 1. Three experienced radiologists were involved in annotating lesions and PI-RADS assignment. The validation set (Dv) comprised 52 patients from a single institution, the remaining 112 pa-tients were used for training (Dt). 200 radiomic features were extracted from intra-lesional and peri-lesional regions on bpMRI. Logistic regression with least absolute shrinkage and selection operator (LASSO) and 10-fold cross-validation was applied on Dt to identify radiomic features associated with MRI- and MRI+ CsPCa to generate corresponding risk scores RMRI-and RMRI+. RbpMRI was further generated by integrating RMRI-and RMRI+. Statistical significance was determined using the Wilcoxon signed-rank test.Results: Both intra-lesional and peri-lesional bpMRI Haralick and CoLlAGe radiomic features were significantly associated with MRI- CsPCa (p < 0.05). Intra-lesional ADC Haralick and CoLlAGe radiomic features were significantly different among MRI- and MRI+ CsPCa (p < 0.05). RbpMRI yielded the highest AUC of 0.82 (95 % CI 0.72-0.91) compared to AUCs of RMRI+ 0.76 (95 % CI 0.63-0.89), and PI-RADS 0.58 (95 % CI 0.50-0.72) on Dv. RbpMRI correctly reclassified 10 out of 14 MRI- CsPCa on Dv.Conclusion: Our preliminary results demonstrated that both intra-lesional and peri-lesional bpMRI radiomic features were significantly associated with MRI CsPCa. These features could assist in CsPCa identification on bpMRI.