Prostate Imaging for Local Recurrence Reporting and Data System for Biparametric Magnetic Resonance Imaging: A Proposal

We investigated a novel dedicated Prostate Imaging for Local Recurrence Reporting and Data System (PI-RRADS) in biochemical recurrence after radiotherapy (RT) and radical prostatectomy (RP) evaluating biparametric magnetic resonance imaging (bpMRI) exams, at 3T MRI of 55 patients. Associating bpMRI and biochemical recurrence data, we calculated bpMRI diagnostic accuracy. Four probability categories, from 1 (very low) to 4 (very high), were distinguished. In 20 patients with radiotherapy, 25% and 75% of lesions were reported as PI-RRADS 3, and 4, respectively. In 35 patients with radical prostatectomy, 7.7% of lesions were included in PI-RRADS 1-2, whereas 40.4% and 51.9% in PI-RRADS 3 and 4 categories, respectively. Excellent agreement and significant correlation between bpMRI and biochemical recurrence were found. BpMRI showed sensitivity, specificity, positive predictive value, negative predictive value, false-posi-tive value, false-negative value, and total diagnostic accuracy of 96.15%, 86.7%, 97.4 %, 81.25%, 13.3%, 3.8% and 94.6%, respectively. BpMRI-based PI-RRADS allows the detection and localization local recurrence in biochemical recurrence after RT and RP contributing in clinical management and treatment.