Time-resolved dynamic contrast-enhanced MR urography for the evaluation of ureteral peristalsis: initial experience.

PURPOSE: To determine the feasibility of time-resolved dynamic contrast-enhanced magnetic resonance urography (MRU) for the evaluation of ureteral peristalsis using a data-sharing 3D gradient echo sequence with spiral k-space filling.

MATERIALS AND METHODS: Eight patients (M=3, F=5, mean 48.1 years) were referred for MRU for the evaluation for renal mass (n=3), hematuria (n=2), urinary tract tuberculosis (n=1), postoperative bladder cancer (n=1), and postoperative ureteric reimplantation (n=1). Dynamic MRU was performed for 120 seconds at 1.5T after intravenous furosemide and gadolinium administration using an oblique sagittal, time-resolved T1 3D gradient echo sequence with 1 second effective temporal resolution. Study quality was assessed based on artifacts and extent of ureteric visualization. Frequency of peristalsis from the renal pelvis to urinary bladder was evaluated for each subject.

RESULTS: A total of 16 ureters were examined. Image quality was good in four ureters, satisfactory in 11 ureters, and poor in one ureter. Mean peristaltic frequency was 3.5 waves per minute (range, 2.5-6.5 waves/minute) in normal ureters (n=11). Five ureters were considered abnormal (one urinary tract tuberculosis and four postsurgical ureters), and all had decreased or no peristalsis (0-1.5 waves per minute).

CONCLUSION: MRU using a time-resolved, data-sharing 3D contrast-enhanced technique is able to demonstrate ureteral peristalsis and permits quantification of ureteral peristaltic frequency.