Prospective comparison of PI-RADS version 2 and qualitative in-house categorization system in detection of prostate cancer : Prospective Comparison of PI-RADSv2

Abstract

<div class="section"> <a class="named-anchor" id="S1"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e263">Background</h5> <p id="P2">Prostate Imaging-Reporting and Data System version 2 (PI-RADSv2) provides standardized nomenclature for interpretation of prostate multiparametric MRI (mpMRI). Inclusion of additional features for categorization may provide benefit to stratification of disease. </p> </div><div class="section"> <a class="named-anchor" id="S2"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e268">Purpose</h5> <p id="P3">To prospectively compare PI-RADSv2 to a qualitative in-house system for detecting prostate cancer on mpMRI. </p> </div><div class="section"> <a class="named-anchor" id="S3"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e273">Study Type</h5> <p id="P4">Prospective</p> </div><div class="section"> <a class="named-anchor" id="S4"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e278">Population</h5> <p id="P5">338 patients who underwent mpMRI May 2015–May 2016, with subsequent MRI/transrectal ultrasound fusion-guided biopsy. </p> </div><div class="section"> <a class="named-anchor" id="S5"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e283">Field Strength</h5> <p id="P6">3T mpMRI [T2W, DWI (ADC map, <i>b</i>-2000 DWI acquisition), and DCE MRI]. </p> </div><div class="section"> <a class="named-anchor" id="S6"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e291">Assessment</h5> <p id="P7">One genitourinary radiologist prospectively read mpMRIs using both in-house and PI-RADSv2 5-category systems. </p> </div><div class="section"> <a class="named-anchor" id="S7"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e296">Statistical Test</h5> <p id="P8">In lesion-based analysis, overall and clinically significant (CS) tumor detection rates (TDR) were calculated for all PI-RADSv2 and in-house categories. Ability of each scoring system to detect cancer was assessed by area under receiver operator characteristic curve (AUC). Within each PI-RADSv2 category, lesions were further stratified by their in-house categories to determine if TDRs can be increased by combining features of both systems. </p> </div><div class="section"> <a class="named-anchor" id="S8"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e301">Results</h5> <p id="P9">In 338 patients (median PSA 6.5[0.6–113.6] ng/mL; age 64[44–84] years), 733 lesions were identified (47% tumor-positive). Predictive abilities of both systems were comparable for all (AUC 76–78%) and CS cancers (AUCs 79%). The in-house system had higher overall and CS TDRs than PI-RADSv2 for categories 3 and 4 (p&lt;0.01 for both), with the greatest difference between the scoring systems seen in lesions scored category 4 (CS TDRs: in-house 65%, PI-RADSv2 22.1%). For lesions categorized as PI-RADSv2=4, characterization of suspicious/indeterminate EPE and equivocal findings across all mpMRI sequences contributed to significantly different TDRs for both systems (TDR range 19–75%, p&lt;0.05). </p> </div><div class="section"> <a class="named-anchor" id="S9"> <!-- named anchor --> </a> <h5 class="section-title" id="d84047e306">Data Conclusion</h5> <p id="P10">PI-RADSv2 behaves similarly to an existing validated system which relies on the number of sequences on which a lesion is seen. This prospective evaluation suggests that sequence positivity and suspicion of EPE can enhance PI-RADSv2 category 4 cancer detection. </p> </div>