title: Time-resolved dynamic contrast-enhanced MR urography for the evaluation of ureteral peristalsis: initial experience.
abstract: OBJECTIVE
  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.
  
  
  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).
  
  
  CONCLUSIONS
  MRU using a time-resolved, data-sharing 3D contrast-enhanced technique is able to demonstrate ureteral peristalsis and permits quantification of ureteral peristaltic frequency.
authors.affiliation: Department of Radiology, New York University Medical Center, New York, New York 10016, USA. sooah.kim@nyumc.org
authors.forename: Sooah
authors.initials: S
authors.lastname: Kim
authors.forename: Jason S
authors.initials: JS
authors.lastname: Jacob
authors.forename: Danny C
authors.initials: DC
authors.lastname: Kim
authors.forename: Rafael
authors.initials: R
authors.lastname: Rivera
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010528:Peristalsis; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014513:Ureter / Q000473:pathology*; D014515:Ureteral Diseases / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium