Real-time MRI of orthotopic ileal neobladder voiding: preliminary findings

The purpose of this preliminary study was to analyze the dynamic changes in the configuration of the neobladder and naïve bladder during voiding using real-time MRI.

This study included 10 male patients who had a radical cystectomy and an ileal orthotopic neobladder due to organ-confined bladder cancer and had good urinary function, and 5 male control volunteers. With the subjects in the lateral decubitus position, real-time MRI was performed during micturition. A sagittal slice orientation was used to depict the bladder and the entire length of the urethra; individual movements along the X-axis and Y-axis of the bottom and top of the neobladder and the naïve bladder were recorded and analyzed. Urodynamic studies (UDS) and video voiding cystourethrography were performed in patients.

Five of the 10 neobladder patients could void in the lateral decubitus position. In normal controls and patients who could void, the bladder outlet bladder moved ventrocranially during micturition. The ileal bladder outlet moved a significantly longer distance than the naïve bladder during micturition (X-axis, -13.4+/-1.5 vs. -3.6+/-4.3 cm, p=0.0014; Y-axis, -10.6+/-0.5 vs. -2.0+/-6.5 cm, p=0.0187). The distance that the bladder top moved between the naïve bladders and the neobladder did not differ. UDS did not show a difference between patients who could and could not void at lateral position.

During micturition, the neobladder was found to rotate and move more dynamically than the naïve bladder. Real-time MRI is useful for assessing dynamic voiding function of orthotopic neobladders.