TY - JOUR T1 - Nuclear Magnetic Resonance: Principles of Blood Flow Imaging JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1161 LP - 1166 VL - 4 IS - 6 AU - Catherine M. Mills AU - Michael Brant-Zawadzki AU - Lawrence E. Crooks AU - Leon Kaufman AU - Phil Sheldon AU - David Norman AU - William Bank AU - Thomas H. Newton Y1 - 1983/11/01 UR - http://www.ajnr.org/content/4/6/1161.abstract N2 - Nuclear magnetic resonance (NMR) imaging with spin-echo techniques defines vascular structures with superb anatomic detail. Contrast agents are not necessary as there is intrinsic contrast between flowing blood and the vascular wall. The signal intensity from blood within the vessel lumen varies with the sequence of gradient and radiofrequency pulses used to generate the image as well as with the velocity of blood flow. Appropriate imaging techniques can optimize anatomic detail, distinguish slow from rapidly flowing blood, and serve to identify marked impairment or complete obstruction of flow in an artery or vein. Some examples of these principles in the intracranial circulation are illustrated. ER -