Demonstration of gravity-dependent lung perfusion with contrast-enhanced magnetic resonance imaging.

Imaging of lung perfusion using contrast-enhanced dynamic magnetic resonance (MR) was performed in both the supine and prone positions in six volunteers. Regions of interest (ROIs) were chosen in the dependent and non-dependent portions of the right lung. The percentage increase in signal intensity (SI) and the mean slope were calculated. In the supine position, the dorsal ROI had a greater increase in SI (236.0% vs. 156.9%, P < 0.05) and a faster rise in the slope of enhancement (55.1%/sec vs. 30.1%/sec, P < 0.05) than the ventral ROI. After changing to the prone position, higher peak enhancement (234.3% vs. 177.4%, P < 0.05) and faster slopes (59.6%/sec vs. 35.3%/sec, P < 0.05) shifted to the anterior ROI. We conclude that dynamic contrast-enhanced MR imaging is sensitive to demonstrate gravitationally dependent differences in lung perfusion.