Phase-contrast velocimetry with hyperpolarized 3He for in vitro and in vivo characterization of airflow

✍ Scribed by Ludovic de Rochefort; Xavier Maître; Redouane Fodil; Laurence Vial; Bruno Louis; Daniel Isabey; Céline Croce; Luc Darrasse; Gabriela Apiou; Georges Caillibotte; Jacques Bittoun; Emmanuel Durand

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 575 KB
• Volume: 55
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20899

✦ Synopsis

Abstract

This paper describes a technique that combines radial MRI and phase contrast (PC) to map the velocities of hyperpolarized gases (^3^He) in respiratory airways. The method was evaluated on well known geometries (straight and U‐shaped pipes) before it was applied in vivo. Dynamic 2D maps of the three velocity components were obtained from a 10‐mm slice with an in‐plane spatial resolution of 1.6 mm within 1 s. Integration of the in vitro through‐plane velocity over the slice matched the input flow within a relative precision of 6.4%. As expected for the given Reynolds number, a parabolic velocity profile was obtained in the straight pipe. In the U‐shaped pipe the three velocity components were measured and compared to a fluid‐dynamics simulation so the precision was evaluated as fine as 0.025 m s^−1^. The technique also demonstrated its ability to visualize vortices and localize characteristic points, such as the maximum velocity and vortex‐center positions. Finally, in vivo feasibility was demonstrated in the human trachea during inhalation. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.