Klein and Pollack [49] noted that MRI has a better sensitivity and specificity than CT for local staging, with the most significant advantage being its ability to distinguish between superficial and deep invasion of the bladder detrusor muscle. For deeply infiltrating tumors (stages T3b-T4b), they concluded that MRI is the most accurate staging technique, making CT unnecessary when MRI is available. Beyersdorff et al [21] concluded that MRI is superior to CT for assessing the depth of invasion in the bladder wall, although both techniques may have difficulty differentiating between tumor and inflammation from previous transurethral biopsy. However, recent studies suggest that adding diffusion-weighted imaging (DWI) to conventional pelvic MRI may aid in distinguishing treatment response and detecting residual/recurrent disease [50]. Some studies have demonstrated the sensitivity and specificity of MRI in distinguishing NMIBC from MIBC ranging from 78% to 98% and 82% to 100% and the sensitivity and specificity for distinguishing organ-confined from non-organ-confined bladder tumors ranging from 90% to 94% and 60% to 94%, respectively [51-54]. Multiparametric MRI, which combines dynamic contrast-enhanced imaging with DWI and T2-weighted imaging, is likely the most optimal MRI technique for local staging of bladder cancer [48,55]. The standardization of bladder cancer staging with multiparametric MRI is facilitated by the Vesical Imaging- Reporting and Data System (VI-RADS) scoring system, which was introduced in 2018 [56]. The VI-RADS uses a 5-point scoring system to estimate the likelihood of detrusor muscle invasion, a poor prognosis indicator that requires radical surgery. Wang et al [57] assessed the ability of VI-RADS score to detect MIBC in a group of patients who had multiparametric MRI before surgery. They concluded that VI-RADS effectively predicts the likelihood of detrusor muscle invasion in bladder cancer and should be considered for evaluation before surgery.
Pretreatment Staging of Urothelial Cancer. Klein and Pollack [49] noted that MRI has a better sensitivity and specificity than CT for local staging, with the most significant advantage being its ability to distinguish between superficial and deep invasion of the bladder detrusor muscle. For deeply infiltrating tumors (stages T3b-T4b), they concluded that MRI is the most accurate staging technique, making CT unnecessary when MRI is available. Beyersdorff et al [21] concluded that MRI is superior to CT for assessing the depth of invasion in the bladder wall, although both techniques may have difficulty differentiating between tumor and inflammation from previous transurethral biopsy. However, recent studies suggest that adding diffusion-weighted imaging (DWI) to conventional pelvic MRI may aid in distinguishing treatment response and detecting residual/recurrent disease [50]. Some studies have demonstrated the sensitivity and specificity of MRI in distinguishing NMIBC from MIBC ranging from 78% to 98% and 82% to 100% and the sensitivity and specificity for distinguishing organ-confined from non-organ-confined bladder tumors ranging from 90% to 94% and 60% to 94%, respectively [51-54]. Multiparametric MRI, which combines dynamic contrast-enhanced imaging with DWI and T2-weighted imaging, is likely the most optimal MRI technique for local staging of bladder cancer [48,55]. The standardization of bladder cancer staging with multiparametric MRI is facilitated by the Vesical Imaging- Reporting and Data System (VI-RADS) scoring system, which was introduced in 2018 [56]. The VI-RADS uses a 5-point scoring system to estimate the likelihood of detrusor muscle invasion, a poor prognosis indicator that requires radical surgery. Wang et al [57] assessed the ability of VI-RADS score to detect MIBC in a group of patients who had multiparametric MRI before surgery. They concluded that VI-RADS effectively predicts the likelihood of detrusor muscle invasion in bladder cancer and should be considered for evaluation before surgery.