title: Clinical evaluation of aortic coarctation with 4D flow MR imaging.
abstract: OBJECTIVE
  To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation.
  
  
  METHODS
  Time-resolved, 3D phase contrast magnetic resonance imaging (MRI) (4D Flow) was used to assess blood flow in the thoracic aorta of 34 individuals: 26 patients with coarctation (22 after surgery or stent placement) and eight healthy volunteers.
  
  
  RESULTS
  Direct comparison of blood flow calculated with 2D and 4D phase contrast data at standard levels for analysis in coarctation patients showed good correlation and agreement (correlation coefficient r = 0.99, limits of agreement = -20% to 20% for collateral blood flow calculations). Abnormal blood flow patterns were demonstrated at peak systole with 4D Flow visualization techniques in the descending thoracic aorta of patients but not volunteers. Marked helical flow was seen in 9 of 13 patients with angulated aortic arch geometries after coarctation repair. Vortical flow was seen in regions of poststenotic dilation.
  
  
  CONCLUSIONS
  4D Flow is a fast and reliable means of evaluating collateral blood flow in patients with aortic coarctation in order to establish hemodynamic significance. It also can detect distorted blood flow patterns in the descending aorta after coarctation repair.
authors.affiliation: Department of Radiology, University of California, San Francisco, California 94143-0628, USA. mdhope@stanfordalumni.org)
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hope
authors.forename: Alison K
authors.initials: AK
authors.lastname: Meadows
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Hope
authors.forename: Karen G
authors.initials: KG
authors.lastname: Ordovas
authors.forename: David
authors.initials: D
authors.lastname: Saloner
authors.forename: Gautham P
authors.initials: GP
authors.lastname: Reddy
authors.forename: Marcus T
authors.initials: MT
authors.lastname: Alley
authors.forename: Charles B
authors.initials: CB
authors.lastname: Higgins
mesh_terms: D000328:Adult; D000465:Algorithms; D001017:Aortic Coarctation / Q000175:diagnosis*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult