Towards Imaging of Cerebral Blood Flow and Metabolism on a Microscopical Scale in Vivo

Abstract

Brain cell function and cerebral blood flow are tightly coupled (Schmidt and Hendrix 1938, Olesen 1971, Leniger-Follert and Hossmann 1979, Sokoloff 1981, Frostig et al. 1990). However, the mechanisms how brain cells and cerebral blood vessels do interact in order to adapt cerebral blood flow to different functional and metabolic needs are unknown, although a variety of potential ways of interactions have been proposed (Lassen 1959, Kuschinsky et al. 1972, Rubio et al. 1975, Lou et al. 1987, Heistad and Kontos, 1983, Iadecola et al. 1991, Dirnagl et al. 1993a). One important reason for this situation is the lack of a suitable technique to study this interaction. An ideal method should assess both aspects, i.e. the functional and/or metabolic state of brain cells on the one hand, and cerebral blood flow on the other hand simultaneously. The spatial resolution of such a method should be at least on the order of the objects of investigation, i.e. brain cells and microvessels, and in order to study the dymamics of the interaction and to avoid artifacts induced by an ex vivo approach, the method preferably should be performed in vivo.