HUMAN LUNG AIR SPACES - POTENTIAL FOR MR-IMAGING WITH HYPERPOLARIZED HE-3

Two healthy volunteers who had inhaled approximately 0.75 L of laser-p olarized helium-3 gas underwent magnetic resonance imaging at 1.5 T wi th fast gradient-echo pulse sequences and small flip angles (<10 degre es). Thick-section (20 mm) coronal images, time-course data (30 images collected every 1.8 seconds), and thin-section (6 mm) images were acq uired. Subjects were able to breathe the gas (12% polarization) withou t difficulty. Thick-section images were of good quality and had a sign al-to-noise ratio (S/N) of 32:1 near the surface coil and 16:1 farther away. The time images showed regional differences, which indicated po tential value for quantitation. High-resolution images showed greater detail and a S/N of approximately 6:1.