title: Rapid measurement of arterial input function in mouse tail from projection phases.
abstract: OBJECTIVE
  To measure the arterial input function (AIF) in a mouse tail at high temporal resolution with signal phase of MR projections.
  
  
  METHODS
  The technique involves the acquisition of one 2D image before injection, followed by a series of projections before, during, and after contrast injection. Differences in the signal phase, relative to the mean preinjection phase, were calculated and converted into a concentration of Gd.
  
  
  RESULTS
  An AIF with a temporal resolution of 100 ms was measured and verified with colorimetry (in a flow phantom) and mass spectrometry analysis (in vivo). The projection-based AIF is expected to better represent the rapid contrast kinetics in the blood following injection, thus improving the accuracy of quantitative dynamic contrast-enhanced-MRI analysis. Colorimetry experiments confirmed that signal phase is preferred over magnitude for a precise determination of an AIF. In-vivo experiments demonstrate the feasibility of our approach in mice.
  
  
  CONCLUSIONS
  AIFs can be measured quickly and precisely using phase from projections. Phase data are sensitive to the flow velocity; but this sensitivity is significantly reduced when flow compensation was used.
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
authors: Jennifer
authors: J
authors: Moroz
authors: Clayton L
authors: CL
authors: Wong
authors: Andrew C
authors: AC
authors: Yung
authors: Piotr
authors: P
authors: Kozlowski
authors: Stefan A
authors: SA
authors: Reinsberg
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005240:Feasibility Studies; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D051379:Mice; D016513:Mice, SCID; D008954:Models, Biological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013623:Tail / Q000098:blood supply*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: arterial input function; colorimetry; dynamic contrast enhanced MRI: contrast agent; flow compensation; phase imaging