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

ABSTRACT 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.