title: Intraindividual quantitative and qualitative comparison of gadopentetate dimeglumine and gadobutrol in time-resolved contrast-enhanced 4-dimensional magnetic resonance angiography in minipigs.
abstract: OBJECTIVE
  The concentration and relaxivities of contrast agents affect quantitative and qualitative image quality in contrast-enhanced time-resolved 4-dimensional magnetic resonance angiography (4D-MRA). Gadobutrol has a high relaxivity and is the only gadolinium (Gd)-based contrast agent approved for clinical use at a 1 M concentration. This promises to confer superior bolus characteristics by generating a steeper and shorter bolus with a higher peak Gd concentration. The purpose of this study was to quantitatively examine bolus characteristics of 1 M gadobutrol compared with 0.5 M gadopentetate dimeglumine and to evaluate image quality in thoracoabdominal 4D-MRA.
  
  
  METHODS
  A total of 7 Goettingen minipigs received dynamic computed tomography (CT) on a clinical 64-slice CT (transverse slices, 80 kV, 20 seconds, 0.3 s/dynamic frame) and 4D-MRA (time-resolved imaging with stochastic trajectories; 1. transverse slices, 30 seconds, 0.49 s/frame; 2. coronal slices, 70 seconds, 1.3 s/frame) on a 1.5-T clinical whole-body magnetic resonance imaging under general anesthesia using gadopentetate dimeglumine and gadobutrol in an intraindividual comparative study. Computed tomography attenuations were converted into Gd concentrations on the basis of previous phantom experiments. Quantitative analysis included measurements of the full width at half maximum, time-to-peak intervals, and peak of each bolus in dynamic CT and transverse 4D-MRA. These studies were carried out at equivalent contrast agent flow rates of 1 mL/s. Quantitative analysis (7 arteries and veins) and qualitative image analysis were performed on coronal thoracoabdominal 4D-MRA studies carried out at flow rates of 1 mL/s and, in the case of gadopentetate dimeglumine, also at molarity-adjusted flow rates of 2 mL/s.
  
  
  RESULTS
  The bolus in both transverse 4D-MRA and dynamic CT was significantly narrower (full width at half maximum), earlier (time to peak), and higher (signal intensity enhancement in 4D-MRA, Gd concentration in dynamic CT) when using gadobutrol instead of gadopentetate dimeglumine at a flow rate of 1.0 mL/s (P = 0.008-< 0.0001). In thoracoabdominal 4D-MRA, the signal intensity level and overall image quality were highest in examinations with gadobutrol, followed by examinations with gadopentetate dimeglumine at flow rates of 2 mL/s, and lowest in examinations with gadopentetate dimeglumine at flow rates of 1 mL/s.
  
  
  CONCLUSIONS
  A more compact bolus shape was observed after administration of gadobutrol compared with gadopentetate dimeglumine in minipigs. This was demonstrated both in 4D-MRA, where Gd concentration, relaxivity, and the image-acquisition technique play a role, and in CT, where the signal intensity depends only on the Gd concentration. The overall image quality was rated higher in examinations with 1.0 M gadobutrol than with 0.5 M gadopentetate dimeglumine.
authors.affiliation: From the *Department of Radiology, University of Bonn, Bonn; †MR and CT Contrast Media Research, Bayer Healthcare, Berlin; and ‡Philips Technologie GmbH Innovative Technologies, Research Laboratories, Aachen, Germany.
authors.forename: Dariusch Reza
authors.initials: DR
authors.lastname: Hadizadeh
authors.forename: Gregor
authors.initials: G
authors.lastname: Jost
authors.forename: Hubertus
authors.initials: H
authors.lastname: Pietsch
authors.forename: Martin
authors.initials: M
authors.lastname: Weibrecht
authors.forename: Michael
authors.initials: M
authors.lastname: Perkuhn
authors.forename: Jack Maria
authors.initials: JM
authors.lastname: Boschewitz
authors.forename: Vera Catharina
authors.initials: VC
authors.lastname: Keil
authors.forename: Frank
authors.initials: F
authors.lastname: Träber
authors.forename: Guido Matthias
authors.initials: GM
authors.lastname: Kukuk
authors.forename: Hans Heinz
authors.initials: HH
authors.lastname: Schild
authors.forename: Winfried Albert
authors.initials: WA
authors.lastname: Willinek
mesh_terms: D000818:Animals; D001158:Arteries / Q000033:anatomy & histology* / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D013556:Swine, Miniature
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol; D019786:Gadolinium DTPA