RecruitingEarly Phase 1Diagnostic testVirtual Histology of the Bladder Wall for Bladder Cancer StagingThis is a phase Ib study of the safety and performance of a novel intravesical contrast-enhanced Magnetic Resonance Imaging protocol for determination of bladder cancer stage prior to transurethral resection of bladder tumor (21 subjects) or prior to radical cystectomy for muscle invasive disease (21 subjects). Subjects will undergo a single MRI study: a pre-contrast, single breath hold image followed by sterile placement of a temporary urethral catheter for instillation of a 50mL solution containing Gadobutrol (4 mM) plus ferumoxytol (5 mM) and then a second, post-contrast image. Images will be reviewed by two dedicated abdominal radiologists, who are blinded to the pathologic staging, for determination of tumor presence and depth of bladder wall penetration.