title: Assessment of flow instabilities in the healthy aorta using flow-sensitive MRI.
abstract: OBJECTIVE
  To assess blood flow velocities and spatial distribution of aortic Reynolds numbers in vivo using flow-sensitive magnetic resonance imaging (MRI) and probe for flow instabilities along the aorta based on an empirical model for physiological pulsatile blood flow.
  
  
  METHODS
  Thirty young healthy volunteers were examined by flow-sensitive MRI at eight imaging planes distributed along the thoracic aorta. Flow, Womersley, Strouhal, Reynolds, and critical Reynolds numbers were calculated and used to assess the presence of flow instabilities.
  
  
  RESULTS
  The average peak Reynolds number was higher in the ascending (≈4500) and descending aorta (≈4200) than in the aortic arch (≈3400). According to the calculated critical Reynolds numbers, flow instabilities were prominent in the ascending (14/30 volunteers) and descending aorta (22/30 volunteers) but not in the aortic arch (3/30 volunteers). A significant difference (P < 0.05) in supracritical peak Reynolds numbers was observed between genders. The supracritical Reynolds number, indicating flow instabilities, significantly correlated (P < 0.05) with body weight (r = 0.34), aortic diameter (r = 0.48), and cardiac output (r = 0.53).
  
  
  CONCLUSIONS
  Flow-sensitive MRI was used to indirectly assess the presence of flow instabilities in vivo. The results in volunteers indicate the presence of flow instabilities in the young healthy aorta with a higher prevalence for men than women.
authors: Department of Radiology, Capital Medical University, Beijing, China.
authors: Aurélien F
authors: AF
authors: Stalder
authors: Alex
authors: A
authors: Frydrychowicz
authors: Max F
authors: MF
authors: Russe
authors: Jan G
authors: JG
authors: Korvink
authors: Jürgen
authors: J
authors: Hennig
authors: Kuncheng
authors: K
authors: Li
authors: Michael
authors: M
authors: Markl
mesh_terms: D000328:Adult; D000465:Algorithms; D001011:Aorta / Q000473:pathology*; D001013:Aorta, Thoracic / Q000473:pathology; D001783:Blood Flow Velocity / Q000502:physiology; D015331:Cohort Studies; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D015995:Prevalence; D011673:Pulsatile Flow