title: Thoracic aorta 3D hemodynamics in pediatric and young adult patients with bicuspid aortic valve.
abstract: BACKGROUND
  To evaluate the 3D hemodynamics in the thoracic aorta of pediatric and young adult bicuspid aortic valve (BAV) patients.
  
  
  METHODS
  4D flow MRI was performed in 30 pediatric and young adult BAV patients (age: 13.9 ± 4.4 (range: [3.4, 20.7]) years old, M:F = 17:13) as part of this Institutional Review Board-approved study. Nomogram-based aortic root Z-scores were calculated to assess aortic dilatation and degree of aortic stenosis (AS) severity was assessed on MRI. Data analysis included calculation of time-averaged systolic 3D wall shear stress (WSSsys ) along the entire aorta wall, and regional quantification of maximum and mean WSSsys and peak systolic velocity (velsys ) in the ascending aorta (AAo), arch, and descending aorta (DAo). The 4D flow MRI AAo velsys was also compared with echocardiography peak velocity measurements.
  
  
  RESULTS
  There was a positive correlation with both mean and max AAo WSSsys and peak AAo velsys (mean: r = 0.84, P < 0.001, max: r = 0.94, P < 0.001) and AS (mean: rS  = 0.43, P = 0.02, max: rS  = 0.70, P < 0.001). AAo peak velocity was significantly higher when measured with echo compared with 4D flow MRI (2.1 ± 0.98 m/s versus 1.27 ± 0.49 m/s, P < 0.001).
  
  
  CONCLUSIONS
  In pediatric and young adult patients with BAV, AS and peak ascending aorta velocity are associated with increased AAo WSS, while aortic dilation, age, and body surface area do not significantly impact AAo hemodynamics. Prospective studies are required to establish the role of WSS as a risk-stratification tool in these patients.
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Bradley D
authors: BD
authors: Allen
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Pim
authors: P
authors: van Ooij
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Alex J
authors: AJ
authors: Barker
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Maria
authors: M
authors: Carr
authors: Department of Medical Imaging, Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.
authors: Maya
authors: M
authors: Gabbour
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Susanne
authors: S
authors: Schnell
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Kelly B
authors: KB
authors: Jarvis
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: James C
authors: JC
authors: Carr
authors: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.|Department Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA.
authors: Michael
authors: M
authors: Markl
authors: Department of Medical Imaging, Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.
authors: Cynthia
authors: C
authors: Rigsby
authors: Division of Pediatric Cardiology, Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.|Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors: Joshua D
authors: JD
authors: Robinson
mesh_terms: D000293:Adolescent; D000465:Algorithms; D001013:Aorta, Thoracic / Q000473:pathology / Q000503:physiopathology*; D001021:Aortic Valve / Q000002:abnormalities* / Q000473:pathology / Q000503:physiopathology; D000082882:Bicuspid Aortic Valve Disease; D001783:Blood Flow Velocity; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods; D005260:Female; D006349:Heart Valve Diseases / Q000473:pathology / Q000503:physiopathology*; 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
keywords: 4D flow MRI; bicuspid aortic valve; pediatrics; wall shear stress
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