title: Time-resolved angiography using inflow subtraction (TRAILS).
abstract: OBJECTIVE
  A novel pseudo-continuous arterial spin labeling based angiographic method called Time-Resolved Angiography using InfLow Subtraction is introduced and used to acquire time-resolved whole-head angiographic data sets in healthy volunteers in a clinical feasible scan time of less than 5 min.
  
  
  METHODS
  Using this new method, in conjunction with a sliding window reconstruction, a temporal resolution of 7.2 ms with a low temporal footprint of 432 ms can be achieved.
  
  
  RESULTS
  Excellent vessel delineation compared to a time-of-flight MRA was demonstrated. Normal variations of the vascular system including the Circle of Willis (CoW) were identified using Time-Resolved Angiography Using Inflow Subtraction. Signal intensities were measured in various vascular segments to quantify the blood transit time.
  
  
  CONCLUSIONS
  In this feasibility study, we showed that Time-Resolved Angiography using InfLow Subtraction can be used to acquire hemodynamic information of the whole head in healthy volunteers with a high temporal and spatial resolution. Further studies in patients that suffer from vascular diseases to explore various flow patterns including longer transit time are needed.
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kopeinigg
authors.forename: Roland
authors.initials: R
authors.lastname: Bammer
mesh_terms: D000328:Adult; D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005240:Feasibility Studies; D005260:Female; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D013113:Spin Labels; D013997:Time Factors
chemical_list: D013113:Spin Labels
keywords: 4D; MRA; SPGR; angiography; arterial spin labeling; noncontrast enhanced; noninvasive; time resolved