Impact of Tumor Shape on Local Staging Accuracy Using VI-RADS in Bladder Cancer: Implications for MRI Protocol Selection

Motivation: Accurate local staging of bladder cancer is essential for guiding treatment decisions. However, the influence of tumor morphology on diagnostic performance of VI-RADS remains unclear. Goal(s): To examine how the shape of bladder tumors influences the diagnostic accuracy of biparametric MRI (bpMRI), which combines T2WI and DWI, compared to multiparametric MRI (mpMRI), which includes T2WI, DWI, and dynamic contrast-enhanced MRI (DCE-MRI). Approach: A retrospective analysis included 506 consecutive treatment-naïve patients with confirmed bladder urothelial carcinoma. Patients were grouped based on tumor shape, and diagnostic performance was evaluated using VI-RADS. Results: bpMRI had significantly lower diagnostic performance for sessile/broad-based tumors compared to papillary tumors. Impact: This study highlights the importance of considering tumor morphology in MRI protocols for bladder cancer. The use of DCE-MRI is crucial for accurate staging of sessile/broad-based tumors.