title: Evaluating contrast kinetics by acquiring 2D images during 3D contrast-enhanced MR angiography.
abstract: OBJECTIVE
  To monitor contrast kinetics by acquiring multiple 2D images during 3D contrast-enhanced magnetic resonance angiography (CE MRA).
  
  
  METHODS
  A 2D real-time autotriggering tool was integrated into a 3D sequence, enabling it to run multiple times during 3D acquisition. Several dummy scans were applied after each transition to maintain the steady state condition of both sequences. The number of the acquired 2D images and their distribution can be adjusted. Each 2D image was saved along with its associated timing. Contrast signal variations over time were plotted, reflecting selective signal measurement over an artery and vein from the saved 2D images.
  
  
  RESULTS
  Different contrast kinetics timings were calculated from the resulting plot. Contrast arrival time to the internal cerebral artery was 13.2 +/- 1.2 seconds and the peak arterial to peak venous (at the confluence of sinuses) enhancement was 6.7 +/- 0.6 seconds. The observed timing could be used for 3D sequence optimization; the saved 2D images are useful in detecting and characterizing vascular abnormalities.
  
  
  CONCLUSIONS
  Integrating 2D and 3D sequences into one sequence to monitor contrast kinetics through the neurovasculature is feasible without the need for extra injections or reduced spatial resolution. The technique can also be used in different parts of the body to extract useful clinical information.
authors.affiliation: Imaging Research Program, Sunnybrook and Women's College Health Sciences Center, Toronto, Ontario, Canada. osama@sten.sunnybrook.utoronto.ca
authors.forename: Osama
authors.initials: O
authors.lastname: Al-Kwifi
authors.forename: Richard
authors.initials: R
authors.lastname: Farb
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Stainsby
authors.forename: Graham A
authors.initials: GA
authors.lastname: Wright
mesh_terms: D016477:Artifacts; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000493:pharmacokinetics*; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA