Impact of the PI-QUAL MRI quality score on histopathological up-staging from MRI fusion biopsy to final prostatectomy specimen.

Purpose: The qualitative heterogeneity of multiparametric MRI (mpMRI) poses significant challenges for the diagnostic pathway of prostate cancer (PCa). The Prostate Imaging Quality Score (PI-QUAL) is a novel tool for the qualitative assessment of mpMRI. Aim of this study was to evaluate the impact of PI-QUAL on consistency of radiological to pathological T-stage.

Methods: Patients undergoing MRI-TRUS fusion biopsy and radical prostatectomy (RP) from 01/2016 to 03/2024 were retrospectively included. PI-QUAL was determined by two expert radiologists and categorised: inadequate (1-2), sufficient (3) and optimal (4-5). Primary endpoint was upstaging from locally confined disease in mpMRI (mrT ≤ 2) to advanced in RP-specimen (pT ≥ 3a). Variables were compared using analysis of variance and χ² or Fisher's exact test. Uni- and multivariate binary regression identified independent predictors.

Results: Of 349 patients included, 18 had PI-QUAL 1-2, 44 PI-QUAL 3 and 287 PI-QUAL 4-5. Patient characteristics, PI-RADS scores and biopsy counts were balanced between these groups. Upstaging from mrT ≤ 2 to pT ≥ 3a was significantly more frequent in PI-QUAL 1-2 (22.4%) and PI-QUAL 3 (22.7%) compared to PI-QUAL 4-5 (10.8%) (p = 0.031). Suboptimal mpMRI harbours an increased risk of upstaging (HR 2.22; 95% CI 1.05-4.71; p = 0.037). Optimal mpMRI quality independently predicts higher PI-RADS grading (PI-RADS ≥ 4) (HR 2.27; 95% CI 1.02-5.00; p = 0.043).

Conclusion: PI-QUAL (≤ 3) significantly influences PI-RADS grading and predicts for upstaging from radiological to pathological staging. In case of suboptimal image quality, repetition of mpMRI should be considered.