Inter-reader variability for quality assessment of synthetically degraded prostate MR images aligned with PIQUAL version 2 - 29/09/26

Doi : 10.1016/j.diii.2026.09.002

Kang-Lung Lee ^a,^b,^c, Jobie Budd ^d,^e, Shu-Huei Shen ^a,^c, Dimitri A Kessler ^b, Chan Kyo Kim ^f, Daniel Margolis ^g, Haytham Shebel ^h, Valdair Francisco Muglia ⁱ, Jorge Abreu-Gomez ^j, Nicola Schieda ^k, Baris Turkbey ^l, Hilde Kjernlie Andersen ^m, Fabien Bryans ^e, Antony Rix ^e, Shuncong Wang ^b, Po-Hsiang Liao ^c,^n,^o, Chao-Yu Guo ^n,^p, Martin Graves ^b, Andrei Purysko ^q, Francesco Giganti ^r,^s, Maarten de Rooij ^t, Tristan Barrett ^b,^⁎

^a Department of Radiology, Taipei Veterans General Hospital, Taipei, 112201, Taiwan

^b Department of Radiology, University of Cambridge, Cambridge, CB2 0QQ, United Kingdom

^c School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan

^d Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, United Kingdom

^e Lucida Medical, Cambridge, CB4 2HY, United Kingdom

^f Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 06351, South Korea

^g Department of Radiology, Weill Cornell Medical College, New York, NY 10065, USA

^h Radiology Department, Urology and Nephrology Center, Mansoura University, Cairo, 35516, Egypt

ⁱ Department of Medical Images, Oncology and Hematology, Ribeirao Preto School of Medicine, University of São Paulo, Ribeirão Preto, 14049-900, Brazil

^j Department of Medical Imaging, University Medical Imaging Toronto, University of Toronto, University Health Network, Mount Sinai Hospital and Women's College Hospital, Toronto, M5G 2M9, Canada

^k Department of Radiology, University of Ottawa, Ottawa, K1H 8L6, Canada

^l Molecular Imaging Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA

^m Collective Minds, Danderyd, 182 33, Sweden

ⁿ Institute of Statistics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan

^o Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, 112201, Taiwan

^p Institute of Public Health, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan

^q Abdominal Imaging Section, Diagnostics Institute, and Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH 44195, USA

^r Department of Radiology, University College London Hospital NHS Foundation Trust, London, NW1 2BU, United Kingdom

^s Division of Surgery and Interventional Science, University College London, London, WC1E 6BT, United Kingdom

^t Department of Medical Imaging, Radboud University Medical Center, Nijmegen, 6525 GA, the Netherlands

^⁎ Corresponding author.

En prensa. Pruebas corregidas por el autor. Disponible en línea desde el Tuesday 29 September 2026

Highlights

•	Radiologists show greatest agreement when assessing prostate MRI quality at extreme degradation levels.
•	Synthetic MR image degradation of the prostate enables systematic evaluation of PI-QUAL v2 criteria.
•	Diffusion-weighted imaging of the prostate shows greater variability due to low signal-to-noise ratio and susceptibility to artifacts.

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Abstract

Purpose

The purpose of this study was to evaluate expert radiologists’ perceptions of the quality of magnetic resonance imaging (MRI) of the prostate for images that underwent controlled degradation.

Materials and methods

Seven-levels of controlled degradations were applied to 10 single-slice image sets, with T2-weighted images degraded using Gaussian noise and blur, and diffusion-weighted images degraded using noise, blur, and elastic deformation. Twelve image sets of varying apparent-diffusion coefficient (ADC)-T2-weighted anatomical mismatch were also included. Ten expert radiologists independently assessed image quality using prostate imaging quality (PI-QUAL) aligned criteria. Inter-reader agreement was evaluated using proportion agreement and Gwet’s agreement coefficient 1 (AC1).

Results

For T2-weighted images, image quality adequacy declined with increasing noise and blur, with inter-reader agreement highest at minimal and severe degradation (AC1 up to 0.98), and lowest at intermediate levels (AC1 as low as -0.03), demonstrating a U-shaped pattern. For diffusion-weighted imaging, image quality adequacy similarly decreased with increasing blur, and warping, while agreement for noise-degraded images increased from moderate at baseline to substantial at the highest noise levels. ADC- T2-weighted alignment agreement was almost perfect for mismatches < 5 mm (AC1, 0.93), but poor for > 5 mm mismatches (AC1, -0.08).

Conclusion

Expert radiologists’ assessment of image quality is subjective, with inter-reader agreement varying with image quality and type. Higher agreement is demonstrated for extreme MRI examinations of optimal or markedly poor quality, with the greatest disagreement at moderate degradation levels. Diffusion-weighted images, in particular, show more variable assessments, highlighting its susceptibility to noise and artifacts.

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Keywords : Diffusion-weighted imaging, Image quality, Inter-reader agreement, PI-QUAL, Prostate MRI, T2-weighted imaging

Abbreviations : ADC, AC1, bpMRI, CNR, DCE, Dmax, DWI, EPI, ESUI, ESUR, mpMRI, MRI, PCa, PI-QUAL, PI-RADS, PZ, SD, SNR, T2WI, TZ