Assessment of Flow Instabilities in the Healthy Aorta Using Flow-Sensitive MRI

作者：Stalder Aurelien F; Frydrychowicz Alex; Russe Max F; Korvink Jan G; Hennig Juergen; Li Kuncheng^*; Markl Michael

来源：Journal of Magnetic Resonance Imaging, 2011, 33(4): 839-846.

DOI：10.1002/jmri.22512

• phase-contrast MRI
• turbulence
• aorta
• Reynolds number
• Womersley number
• Strouhal number

Purpose: 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.
Materials and 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 (approximate to 4500) and descending aorta (approximate to 4200) than in the aortic arch (approximate to 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).
Conclusion: 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.

• 出版日期2011-4
• 单位首都医科大学