title: Renal arteries: optimization of three-dimensional gadolinium-enhanced MR angiography with bolus-timing-independent fast multiphase acquisition in a single breath hold.
abstract: OBJECTIVE
  To compare two different three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiographic techniques.
  
  
  METHODS
  In 26 patients suspected of having renal artery stenosis, results with fast multiphase 3D MR angiography were compared to those with standard 3D MR angiography in 37 patients. With both techniques, 31-second breath-hold acquisitions were performed. Multiphase angiography comprised five discrete 6.4-second acquisitions without bolus timing, and standard angiography comprised a single acquisition based on test-bolus timing. Two readers evaluated images obtained with both techniques in terms of image quality, artifacts, and vessel conspicuity. Accuracy of findings on the multiphase 3D MR angiograms for assessment of renal artery stenosis was determined by comparing them to digital subtraction angiograms and surgical findings.
  
  
  RESULTS
  In the early arterial phase, multiphase 3D MR angiograms showed no image degradation by venous overlay, whereas standard 3D MR angiograms depicted at least minor overlay in 53 of 83 renal arteries (P < .001). Less parenchymal enhancement in the early arterial phase resulted in a higher vessel conspicuity for the divisions and segmental arteries (P < .001). Both readers detected and correctly graded 18 of 20 stenoses on the multiphase angiograms with almost perfect interobserver agreement (kappa > 0.89).
  
  
  CONCLUSIONS
  Renal multiphase 3D MR angiography is an accurate technique requiring no bolus timing. The performance of early arterial phase imaging leads to improved depiction, particularly of the distal renovascular tree, compared to that with standard single-phase 3D MR angiography.
authors.affiliation: Department of Radiology, German Cancer Research Center, Heidelberg, Germany.
authors.forename: S O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: M
authors.initials: M
authors.lastname: Bock
authors.forename: M V
authors.initials: MV
authors.lastname: Knopp
authors.forename: M
authors.initials: M
authors.lastname: Essig
authors.forename: G
authors.initials: G
authors.lastname: Laub
authors.forename: H
authors.initials: H
authors.lastname: Hawighorst
authors.forename: I
authors.initials: I
authors.lastname: Zuna
authors.forename: F
authors.initials: F
authors.lastname: Kallinowski
authors.forename: G
authors.initials: G
authors.lastname: van Kaick
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D012078:Renal Artery Obstruction / Q000175:diagnosis / Q000601:surgery
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA