Functional MR microscopy of the lung using hyperpolarized He-3

A new strategy designed to provide functional magnetic resonance images of the lung in small animals at microscopic resolution using hyperpolarized He -3 is described. The pulse sequence is based on a combination of radial acq uisition (RA) and CINE techniques, referred to as RA-CINE, and is designed for use with hyperpolarized He-3 to explore lung ventilation with high temp oral and spatial resolution in small animal models. Ventilation of the live guinea pig is demonstrated with effective temporal resolution of 50 msec a nd in-plane spatial resolution of <100 mu m using hyperpolarized He-3. The RA-CINE sequence allows one to follow gas inflow and outflow in the airways as well as in the distal part of the lungs. Regional analysis of signal in tensity variations can be performed acid can help assess functional lung pa rameters such as residual gas volume and lung compliance to gas inflow. (C) 1999 Wiley-Liss, Inc.