Inter-reader agreement of the PI-QUAL score for prostate MRI quality in the NeuroSAFE PROOF trial.

The Prostate Imaging Quality (PI-QUAL) score assesses the quality of multiparametric MRI (mpMRI). A score of 1 means all sequences are below the minimum standard of diagnostic quality, 3 implies that the scan is of sufficient diagnostic quality, and 5 means that all three sequences are of optimal diagnostic quality. We investigated the inter-reader reproducibility of the PI-QUAL score in patients enrolled in the NeuroSAFE PROOF trial.

We analysed the scans of 103 patients on different MR systems and vendors from 12 different hospitals. Two dedicated radiologists highly experienced in prostate mpMRI independently assessed the PI-QUAL score for each scan. Interobserver agreement was assessed using Cohen's kappa with standard quadratic weighting (κw) and percent agreement.

The agreement for each single PI-QUAL score was strong (κw = 0.85 and percent agreement = 84%). A similar agreement (κw = 0.82 and percent agreement = 84%) was observed when the scans were clustered into three groups (PI-QUAL 1-2 vs PI-QUAL 3 vs PI-QUAL 4-5). The agreement in terms of diagnostic quality for each single sequence was highest for T2-weighted imaging (92/103 scans; 89%), followed by dynamic contrast-enhanced sequences (91/103; 88%) and diffusion-weighted imaging (80/103; 78%).

We observed strong reproducibility in the assessment of PI-QUAL between two radiologists with high expertise in prostate mpMRI. At present, PI-QUAL offers clinicians the only available tool for evaluating and reporting the quality of prostate mpMRI in a systematic manner but further refinements of this scoring system are warranted.

• Inter-reader agreement for each single Prostate Imaging Quality (PI-QUAL) score (i.e., PI-QUAL 1 to PI-QUAL 5) was strong, with weighted kappa = 0.85 (95% confidence intervals: 0.51 - 1) and percent agreement = 84%. • Interobserver agreement was strong when the scans were clustered into three groups according to the ability (or not) to rule in and to rule out clinically significant prostate cancer (i.e., PI-QUAL 1-2 vs PI-QUAL 3 vs PI-QUAL 4-5), with weighted kappa = 0.82 (95% confidence intervals: 0.68 - 0.96) and percent agreement = 84%. • T2-weighted acquisitions were the most compliant with the Prostate Imaging Reporting and Data System (PI-RADS) v. 2.0 technical recommendations and were the sequences of highest diagnostic quality for both readers in 95/103 (92%) scans, followed by dynamic contrast enhanced acquisition with 81/103 (79%) scans and lastly by diffusion-weighted imaging with 79/103 (77%) scans.

European radiology. 2021 Jul 29 [Epub ahead of print]

Francesco Giganti, Eoin Dinneen, Veeru Kasivisvanathan, Aiman Haider, Alex Freeman, Alex Kirkham, Shonit Punwani, Mark Emberton, Greg Shaw, Caroline M Moore, Clare Allen

Department of Radiology, University College London Hospital NHS Foundation Trust, London, UK. ., Division of Surgery & Interventional Science, University College London, 3rd Floor, Charles Bell House, 43-45 Foley St, London, W1W 7TS, UK., Department of Pathology, University College London Hospital NHS Foundation Trust, London, UK., Department of Radiology, University College London Hospital NHS Foundation Trust, London, UK.