Direct Comparison of PI‐RADS Version 2 and 2.1 in Transition Zone Lesions for Detection of Prostate Cancer: Preliminary Experience

Abstract

BackgroundThere appears to be less agreement in the identification of cancers in the transition zone (TZ), which is not as reliable as those in peripheral zone when using the Prostate Imaging Reporting and Data System (PI‐RADS) version 2 (v2). In response to such shortcomings, the updated version 2.1 was introduced, which incorporated diffusion‐weighted imaging (DWI) into category 2 and clarified lexicons.PurposeTo compare the diagnostic performance for the detection of clinically significant TZ prostate cancers (csPCa) and interreader agreement between PI‐RADS v2.1 and v2.Study TypeRetrospective study.PopulationIn all, 142 patients, 201 TZ lesions.Field Strength/Sequence3.0T; T2‐weighted image and DWI.AssessmentLesions were scored by three independent readers using PI‐RADS v2 and v2.1.Statistical TestsThe sensitivity and specificity at category ≥3 were compared between v2 and v2.1 using the generalized estimating equation model. Detection rates for csPCa of upgraded and downgraded lesions in the use of PI‐RADS v2.1 from v2 were assessed. Interreader agreement was assessed using κ statistics.ResultsPI‐RADS v2.1 showed a higher sensitivity and specificity (94.5% and 60.9%) than v2 (91.8% and 56.3%) for category ≥3 lesions in the detection of csPCa, although not significantly. Of eight upgraded lesions from category 2 to 3 (2 + 1) with an incorporated DWI, 50% (4/8) were csPCa. This was significantly higher than category 2 lesions (4.4%; P = 0.003). No csPCa was detected among the 22.8% (46/201) downgraded lesions. There was a moderate interreader agreement for scores ≥3 (κ = 0.565) in v2.1, which was slightly higher than that for v2 (κ = 0.534), although not significantly.Data ConclusionPI‐RADS v2.1 provides moderate and comparable interreader agreement at category ≥3 than v2 in the TZ lesions. Upgraded lesions from category 2 to 3 demonstrated a higher detection rate of csPCa than category 2 lesions in v2.1.Level of Evidence4Technical Efficacy Stage2 J. Magn. Reson. Imaging 2020;52:577–586.

Use of Radiomics to Improve Diagnostic Performance of PI-RADS v2.1 in Prostate Cancer

“…One of the major modifications in version 2.1 is the diagnostic criteria for the transitional zone PCa of low T2WI scores. When comparing the performance between version 2 and 2.1 for characterization of suspected PCa, several studies suggested that AUC tended to be higher in version 2.1 than in version 2 without statistical significance ( 6 – 8 ). It must be noted that PI-RADS v2.1 still showed a high false positive rate (moderate specificity) for PCa diagnosis, similar to that with PI-RADS v2.…”

“…In 2015, version 2 was described to further improve reporting accuracy, and now has seen a broad uptake ( 4 , 5 ). In 2019, PI-RADS version 2.1 was newly described, with several studies suggesting that version 2.1 could be preferable than version 2 for the evaluation of transition zone PCa ( 6 – 8 ). PI-RADS is now playing an increasingly prominent role in PCa diagnosis ( 9 , 10 ).…”

Detection limits of significant prostate cancer using multiparametric MR and digital rectal examination in men with low serum PSA: Up-date of the Italian Society of Integrated Diagnostic in Urology

“…Since, PI-RADS 3 does not identify the same risk of cancer in different prostate zones, the predictive value of PI-RADS 3 should be considered as low in the TZ respect to PZ. However, the estimating of the predictive value of PI-RADS 3 lesions has methodological bias because it do not represent the primary endpoint of published studies, (58). Their results demonstrated that the last version has both higher sensitivity and specificity for the overall detection of PCa for category higher than 3 lesions, independently of the prostatic zone.…”

Assessment of DCE Utility for PCa Diagnosis Using PI-RADS v2.1: Effects on Diagnostic Accuracy and Reproducibility

“…However, since the κ values depend on many factors (including the prevalence of disease) [28], it makes no sense to compare κ value obtained in different studies. To account for this, PI-RADS v2 and 2.1 scoring should both be assigned on the same group of patients, as done in recent studies by Tamada et al and Byun et al [24,25].…”

“…Because of the recent introduction of PI-RADS v2.1, studies evaluating its accuracy are few [24,25], and none of these aims to investigate the actual value of DCE for the PI-RADS assignment of PCa lesions.…”