Contents

05 October 1990
Vol 250, Issue 4977

About The Cover

Magnetic resonance image of a transverse slice of a monkey head through the eyes showing contrast based on blood microcirculation. This image was obtained from signals of tissue water, whose magnetic resonance properties were modified by a vascular contrast agent, 15 seconds after injection. See page 53. [Visualization by Geoffrey Sobering, In Vivo Nuclear Magnetic Resonance Research Center, National Institutes of Health]