This prospective diagnostic accuracy study compares computed tomography (CT) and multiparametric magnetic resonance imaging (MRI) using the Vesical Imaging-Reporting and Data System (VI-RADS) for local staging of newly diagnosed bladder cancer. All participants undergo both imaging modalities prior to transurethral resection of the bladder tumor (TURBT) or cystectomy. Histopathology serves as the reference standard.
Accurate local staging is crucial for distinguishing non-muscle-invasive from muscle-invasive bladder cancer and guiding treatment decisions. While CT is widely used in clinical practice, MRI with VI-RADS has demonstrated higher diagnostic performance in previous retrospective and meta-analytic studies. However, prospective paired comparisons in the same patients are limited. In this single-center prospective study, newly diagnosed bladder cancer patients undergo cystoscopy, contrast-enhanced CT, and multiparametric MRI prior to definitive histopathological sampling. Two radiologists independently assess imaging in a blinded research setting. Diagnostic performance of MRI and CT is compared using paired statistical analyses, with additional evaluation of interobserver agreement and tumor characteristics.
Study Type
OBSERVATIONAL
Enrollment
150
Oslo University Hospital
Oslo, Norway
RECRUITINGDiagnostic Accuracy for Detection of Muscle-Invasive Bladder Cancer (≥T2)
The primary outcome is the diagnostic accuracy of multiparametric magnetic resonance imaging (MRI) using the Vesical Imaging-Reporting and Data System (VI-RADS) compared with contrast-enhanced computed tomography (CT) for the detection of muscle-invasive bladder cancer (pathological stage ≥T2). Sensitivity and specificity will be calculated using histopathology from transurethral resection of the bladder tumor, re-TURBT, and/or cystectomy as the reference standard.
Time frame: From imaging to final histopathological reference standard (up to 12 months)
Positive and Negative Predictive Values
Positive predictive value (PPV) and negative predictive value (NPV) of MRI (VI-RADS) and CT for detection of muscle-invasive bladder cancer (≥T2), calculated using histopathology as the reference standard.
Time frame: From imaging to final histopathological reference standard (up to 12 months)
Interobserver Agreement for MRI and CT Tumor Staging
Interobserver agreement between two independent radiologists for MRI VI-RADS scoring and CT-based T-stage assessment, quantified using weighted kappa statistics in a blinded research reading setting.
Time frame: During blinded image evaluation following imaging acquisition
Proportion of correctly classified Tumor T-stage (Ta-T4) by MRI and CT
Proportion of correctly classified tumor T-stage (Ta-T4) by MRI and CT compared with histopathological staging from TURBT and/or cystectomy.
Time frame: From imaging to final histopathological reference standard (up to 12 months)
Diagnostic accuracy of MRI and CT for detection of muscle-invasive bladder cancer within tumor subgroups
Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRI and CT for detection of muscle-invasive bladder cancer, assessed within predefined tumor subgroups (tumor size, morphology, tumor location and multiplicity), using histopathology as the reference standard.
Time frame: From imaging to final histopathological reference standard (up to 12 months)
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