Prostate MRI quality assessment using PI-QUAL version 2: Comparative analysis between 1.5 T and 3 T scanners and its association with T-staging agreement

Purpose To assess prostate MRI image quality using Prostate Imaging Quality (PI-QUAL) version 2, to compare quality distributions between 1.5 T and 3 T MRI scanners, and to evaluate the association between image quality and concordance of MRI-based and pathological T-staging. Materials and methods This retrospective study included 416 patients who underwent preoperative prostate MRI followed by radical prostatectomy between December 2021 and August 2024. MRI examinations were performed using one 1.5 T scanner and two 3 T scanners. Image quality was independently evaluated by two radiologists using PI-QUAL v2. MRI-based T-staging (mrT2, mrT3a, or mrT3b) was determined by consensus and compared with pathological T-staging. Differences in PI-QUAL scores were analyzed across scanners, and the association between PI-QUAL score and T-stage mismatch was evaluated using logistic regression. Inter-observer agreement was assessed using percent agreement and Gwet’s agreement coefficients. Results The proportion of examinations with acceptable image quality (PI-QUAL v2 ≥ 2) was significantly higher in 3 T group than in 1.5 T group (85.8% vs. 75.2%, p = 0.004). Among the three MRI scanners, the proportion of examinations with acceptable image quality differed significantly across scanners, with the highest proportion observed in MR2 (1.5 T: 75.2%, MR1: 82.6%, MR2: 89.1%; p = 0.026). PI-QUAL scores were significantly higher in cases with concordant MRI-based and pathological T-staging than in mismatched cases ( p = 0.010). Higher PI-QUAL scores were independently associated with improved T-staging agreement (odds ratio, 1.59; 95% confidence interval, 1.17–2.16; p = 0.003), particularly in the 3 T subgroup. Inter-observer agreement for PI-QUAL v2 parameters was generally substantial to almost perfect, with variability observed for diffusion-weighted imaging parameters. Conclusion Higher prostate MRI image quality, as assessed by PI-QUAL v2, is significantly associated with improved concordance between MRI-based and pathological T-staging. These findings support the clinical relevance of standardized image quality assessment and highlight the role of PI-QUAL v2 as a practical quality assurance tool in prostate MRI.