title: Functional, dynamic, and anatomic MR urography: feasibility and preliminary findings.
abstract: OBJECTIVE
  The authors assessed the feasibility of using magnetic resonance (MR) urography to acquire functional, dynamic, and anatomic information in human subjects with normal and hydronephrotic kidneys.
  
  
  METHODS
  In subjects known to have or suspected of having hydronephrosis, split renal filtration fractions were measured with a customized magnetization-prepared, inversion-prepared gradient-recalled echo sequence to determine the T1 of flowing blood in the inferior vena cava and aorta before and after contrast medium administration and in the renal veins and arteries after contrast medium administration. Multiple timed sets of coronal fast spoiled gradient-echo 70 degrees flip-angle images were acquired before and after contrast medium administration to derive MR renograms from changes in the signal intensity of the cortex and medulla. Precontrast T2-weighted images were obtained with a three-dimensional fast spoiled gradient-echo maximum intensity projection pulse sequence, and postcontrast T1 maximum intensity projection images were also obtained to depict the renal anatomy.
  
  
  RESULTS
  Split filtration fraction differentiated normal from hydronephrotic kidneys. MR renograms depicted vascular, tubular, and ductal phases and differentiated between normal and hydronephrotic kidneys (P < .05, n = 20). Contrast medium dose correlated with the peak of the cortical signal intensity curves on the renogram (r = 0.7, P < .0005; n = 20). The sensitivities for the visual determination of hydronephrosis and unilateral delayed excretion of contrast material were both 100%, and the specificities were 64% and 85%, respectively.
  
  
  CONCLUSIONS
  The preliminary findings show promise for the use of MR urography in the comprehensive assessment of renal function, dynamics, and anatomy.
authors.affiliation: Department of Radiology, University of California-Davis, Medical Center, Research Imaging Center, Sacramento 95817, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Katzberg
authors.forename: M H
authors.initials: MH
authors.lastname: Buonocore
authors.forename: M
authors.initials: M
authors.lastname: Ivanovic
authors.forename: C
authors.initials: C
authors.lastname: Pellot-Barakat
authors.forename: J M
authors.initials: JM
authors.lastname: Ryan
authors.forename: K
authors.initials: K
authors.lastname: Whang
authors.forename: J M
authors.initials: JM
authors.lastname: Brock
authors.forename: C D
authors.initials: CD
authors.lastname: Jones
mesh_terms: D000328:Adult; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007668:Kidney / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014563:Urodynamics; D014567:Urography / Q000379:methods*