Comparing Radiologist Performance in Diagnosing Clinically Significant Prostate Cancer With Biparametric Versus Size‐Selective Diffusion MRI

BACKGROUND: Biparametric MRI (bpMRI) was interpreted using Prostate Imaging Reporting and Data System (PI-RADS) version 2.1, a system associated with relatively low specificity. Selective size imaging using filters via diffusion times MRI (SSIFT-MRI) is a novel imaging technique that may improve diagnostic performance. PURPOSE: To compare the diagnostic performance of bpMRI versus SSIFT-MRI for diagnosing clinically significant prostate cancer (csPCa). STUDY TYPE: Prospective. POPULATION: Hundred and eighteen men (age: 70 ± 7 years) with suspected csPCa. FIELD STRENGTH/SEQUENCE: Pulsed and oscillating gradient spin-echo sequences at 3 T. BpMRI included three-plane T2-weighted imaging and diffusion-weighted imaging. ASSESSMENT: csPCa status was pathologically determined via ultrasound-guided biopsy or prostatectomy. Three radiologists assessed bpMRI and SSIFT-MRI for identifying csPCa lesions, and we further compared the performance of combining PI-RADS with SSIFT-MRI against that of bpMRI. STATISTICAL TESTS: Area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnostic performance; bootstrap resampling for comparing AUC; McNemar's test for comparing sensitivity, specificity, PPV, NPV, and accuracy. A p-value < 0.05 was considered significant. RESULTS: Per-patient accuracy was significantly higher for SSIFT-MRI (reader 1: 85% vs. 68%; reader 2: 80% vs. 64%; reader 3: 77% vs. 65%). Per-patient specificity (reader 1: 71% vs. 27%; reader 2: 58% vs. 11%; reader 3: 58% vs. 20%) and PPV (reader 1: 84% vs. 67%; reader 2: 78% vs. 64%; reader 3: 77% vs. 65%) were significantly higher for SSIFT-MRI. Combining PI-RADS with SSIFT-MRI yielded significantly higher AUCs and accuracy than bpMRI alone (AUC and accuracy for reader 1: 0.89% and 83%; reader 2: 0.80% and 73%; reader 3: 0.75% and 72%). DATA CONCLUSION: SSIFT-MRI for csPCa had similar or higher diagnostic performance compared with bpMRI. The combination approach provided significantly higher AUC and accuracy than bpMRI. EVIDENCE LEVEL: 1. STAGE OF TECHNICAL EFFICACY: 2.