In Vivo Comparison of 2D and 3D T2* in the Rat Lung Using Hyperpolarized Helium-3 MRI at 1.5 T

Kyle Hill^1,2, Jos-Manuel Prez-Snchez², Roberta Santarelli², Mathieu Sarracanie², Pascal Hagot², Marlies Friese², Xavier Matre², Luc Darrasse²

The T2* of hyperpolarized helium-3 in the lungs has shown promise in characterizing lung microstructure due to its sensitivity to local gradients caused by gas-tissue interfaces, whose abundance per unit volume changes with lung inflation and pathological modification. Despite the lungs three-dimensional structure, most measurements of helium-3 T2* have been performed using projection imaging which neglects the complex microstructures effects. This work uses five rats in vivo to compare the T2* in a projection image with 3D imaging and shows that 3D is necessary to detect statistically different local phenomena that may not be apparent in projection imaging.