Measuring Cerebral Blood Flow: History

This chapter considers the history of cerebral blood flow measurement. The first study of cerebral hemodynamics was by Mosso in the late nineteenth century. Using a special self-constructed device on subjects who had suffered head trauma, he found that brain volume changed when mental activity occurred. A half century later, Kety developed a method to measure cerebral blood flow using an inert gas as a diffusible tracer that accumulated in the brain after inhalation. Lassen extended Kety’s method to use radioisotopes. The development of tomography made noninvasive quantitative measurements of brain function possible. Accurate measurements of cerebral blood flow became very important for the clinical diagnosis of various neural diseases as well as for understanding fundamental neurophysiology. PET with radioactive tracers such as oxygen-15 gas and fluorine-18 FDG contributed greatly to knowledge of brain energy physiology and circulatory metabolism. The many technological and scientific breakthroughs made by our predecessors are briefly described here.