Interobserver agreement of non-parallel transmission technology zoomed-diffusion-weighted imaging (DWI) for ordinal biparametric Vesical Imaging-Reporting and Data System (VI-RADS)-based scoring in bladder cancer lesions ≥1 cm.

Authors

Dianyu Wang, Zhenming Zhang, Yanjing Wang, Zhijia Wang, Hanyun Zhang, Cancan Cui, Zhao Zhang, Naiming Xue, Mengchao Zhang, Lin Liu

Published in

Quantitative imaging in medicine and surgery. Volume 16. Issue 10. Pages 801. Oct 01, 2026. Epub Sep 14, 2026.

Abstract

Preoperative assessment of muscle invasion in bladder cancer using the Vesical Imaging-Reporting and Data System (VI-RADS) relies heavily on diffusion-weighted imaging (DWI), but conventional single-shot echo-planar imaging diffusion-weighted imaging (ss-EPI-DWI) may be limited by image distortion and artifacts, potentially affecting interobserver agreement. Zoomed diffusion-weighted imaging without parallel transmission technology (non-pTx zoomed-DWI) may improve image quality. This study aimed to compare the interobserver agreement of non-pTx zoomed-DWI versus conventional ss-EPI-DWI for ordinal biparametric VI-RADS-based scoring in bladder cancer lesions ≥1 cm across different morphological types among radiologists with varying levels of experience.
This retrospective single-center study included patients with pathologically confirmed bladder cancer who underwent preoperative biparametric magnetic resonance imaging (MRI), including T2-weighted imaging (T2WI), conventional ss-EPI-DWI, and non-pTx zoomed-DWI, before transurethral resection of bladder tumor or radical cystectomy. Three radiologists independently assigned ordinal biparametric VI-RADS-based F-scores from 1 to 5 for each eligible lesion using ss-EPI-DWI and non-pTx zoomed-DWI datasets separately. T2WI was used for lesion localization and morphological classification, whereas the corresponding DWI sequence, including high-b-value DWI images and apparent diffusion coefficient (ADC) maps, was used to assign ordinal biparametric VI-RADS-based F-scores according to the standard VI-RADS scoring criteria. Subjective image quality was rated on a 4-point scale. Interobserver agreement was assessed using linear weighted kappa statistics with 95% confidence intervals.
A total of 162 patients (138 males, 24 females; median age 67 years) with 214 eligible bladder cancer lesions were included. Non-pTx zoomed-DWI provided significantly higher subjective image quality scores than ss-EPI-DWI for both readers (P<0.001). Based on the original ordinal VI-RADS-based F-scores, overall pairwise interobserver agreement was good with ss-EPI-DWI (linear weighted κ=0.708-0.761) and excellent with non-pTx zoomed-DWI (linear weighted κ=0.851-0.870). In morphology-specific analyses, agreement also improved with non-pTx zoomed-DWI across lesion subgroups. The improvement was particularly evident in broad-based nodules, for which agreement increased from good with ss-EPI-DWI (κ=0.700-0.752) to excellent with non-pTx zoomed-DWI (κ=0.892-0.919), and in nodules with pedicles, for which agreement improved from moderate-to-good (κ=0.535-0.640) to good-to-excellent (κ=0.786-0.847).
Non-pTx zoomed-DWI improved subjective image quality and interobserver agreement for ordinal biparametric VI-RADS-based scoring in bladder cancer lesions ≥1 cm compared with conventional ss-EPI-DWI. These findings suggest that non-pTx zoomed-DWI may support more consistent MRI-based assessment of muscle invasion risk, particularly in morphologically complex lesions. Further prospective studies with lesion-level pathological correlation are needed to determine whether improved agreement translates into improved diagnostic accuracy.

PMID:
42861192
Bibliographic data and abstract were imported from PubMed on 12 Oct 2026.

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