A Quantitative Modification of VI-RADS for Bladder Cancer at the Ureteral Orifice: A Reader Study on MRI With Varying Experience Levels.

BACKGROUND

While the current Vesical Imaging Reporting and Data System (VI-RADS) provides a valuable tool for evaluating bladder cancer, it is not tailored to the ureteral orifices and primarily relies on subjective evaluation.

PURPOSE: To identify significant parameters from MRI for diagnosing muscle-invasive bladder cancer (MIBC) at the ureteral orifice, and to evaluate their incremental value to VI-RADS for readers of varying experience.

STUDY TYPE: Retrospective.

POPULATION: Development cohort: 81 patients with ureteral orifice bladder tumors (mean age, 68 ± 9; 60 men). External validation cohort: 34 patients (mean age, 63 ± 5; 22 men).

FIELD STRENGTH/SEQUENCE: 3.0 T; fast spin-echo T2-weighted imaging, single-shot echo planar diffusion-weighted imaging, 3D spoiled gradient echo T1-weighted dynamic contrast-enhanced imaging.

ASSESSMENT: Four radiologists of varying experience independently assigned VI-RADS scores. Quantitative parameters (tumor length, tumor contact length [TCL], stalk width [SW], and Ktrans) and qualitative parameters were assessed. Pathology was the reference standard.

STATISTICAL TESTS: Intraclass correlation coefficient, weighted κ analysis, independent samples t-test, Mann-Whitney U test, chi-square test, receiver operating characteristic curve analysis, univariate and multivariate logistic regression, 1000 bootstrap resamples, DeLong's test, and McNemar's test with Bonferroni correction. Significance was defined as p < 0.05, with p < 0.008 for multiple comparisons.

RESULTS

Multivariate analysis identified TCL (odds ratio [OR] = 1.12) and stalk width (OR = 1.74) as independent predictors. In both cohorts, the TCL + SW-modified VI-RADS significantly improved sensitivity over the original VI-RADS for diagnosing MIBC at the ureteral orifice in two junior radiologists. The TCL + SW-modified VI-RADS did not significantly improve sensitivity compared with the TCL-modified VI-RADS in either cohort (p = 0.25-0.50).

DATA

CONCLUSION

The integration of TCL and stalk width into the VI-RADS improves diagnostic performance for MIBC at the ureteral orifice, particularly for less-experienced radiologists. Nevertheless, external validation in larger, multicenter cohorts is required.

EVIDENCE LEVEL: 3.

TECHNICAL EFFICACY: Stage 2.