Measurement of Apparent Long-Range Diffusion of 3He Using Pulsed Gradient Spin Echo T2 in the Rat Lung at Low Magnetic Field Strength

Giles Santyr^1,2, Ryan Kraayvanger^1,2, Xiaojun Xu^1,2, William Dominguez-Viqueira^1,2

The Apparent Diffusion Coefficient (ADC) of hyperpolarized 3He in the lung has recently been shown to have heightened sensitivity to lung diseases, such as COPD, when measured in the long range diffusion regime (i.e. ~seconds). However, the susceptibility induced gradients within the lung limit the time-scale and pulse sequences possible for measuring the ADC on typical clinical MR systems (1.5 3.0 T). We explore the use of a Pulsed Gradient Spin Echo technique at low magnetic field strength (1-100 mT), where susceptibility induced gradients are greatly reduced, to measure ADC of hyperpolarized 3He.