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

Abstract

The role of dynamic contrast-enhanced-MRI (DCE-MRI) for Prostate Imaging-Reporting and Data System (PI-RADS) scoring is a controversial topic. In this retrospective study, we aimed to measure the added value of DCE-MRI in combination with T2-weighted (T2W) and diffusion-weighted imaging (DWI) using PI-RADS v2.1, in terms of reproducibility and diagnostic accuracy, for detection of prostate cancer (PCa) and clinically significant PCa (CS-PCa, for Gleason Score ≥ 7). 117 lesions in 111 patients were identified as suspicion by multiparametric MRI (mpMRI) and addressed for biopsy. Three experienced readers independently assessed PI-RADS score, first using biparametric MRI (bpMRI, including DWI and T2W), and then multiparametric MRI (also including DCE). The inter-rater and inter-method agreement (bpMRI- vs. mpMRI-based scores) were assessed by Cohen's kappa (κ). Receiver operating characteristics (ROC) analysis was performed to evaluate the diagnostic accuracy for PCa and CS-PCa detection among the two scores. Inter-rater agreement was excellent for the three pairs of readers (κ ≥ 0.83), while the inter-method agreement was good (κ ≥ 0.73). Areas under the ROC curve (AUC) showed similar high-values (0.8 ≤ AUC ≤ 0.85). The reproducibility of PI-RADS v2.1 scoring was comparable and high among readers, without relevant differences, depending on the MRI protocol used. The inclusion of DCE did not influence the diagnostic accuracy.

Keywords: DCE; PI-RADS; ROC analysis; magnetic resonance imaging; mpMRI; prostate cancer; reproducibility.

Figure 1

Comparison of ROC curves showing diagnostic accuracy of mpMRI-based (continuous lines) and bpMRI-based (dashed line) PI-RADS v2.1 scoring for the three readers: (a) ROC curves showing diagnostic accuracy for PCa detection; (b) ROC curves showing diagnostic accuracy for CS-PCa detection. Points, triangles, squares and diamonds correspond to PI-RADS thresholds; and, (c) ROC curves showing diagnostic accuracy for PCa detection in peripheral zone (PZ). Please note that for diagnostic accuracy analysis in PZ PCa lesion detection, the total sample consisted of 105 PZ lesions, of which 66 positive to biopsy.