Fundamentals of Magnetic Resonance

Abstract

Magnetic resonance methods currently in use for the assessment of human subjects include magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and functional magnetic resonance imaging (fMRI). MRI provides detailed information regarding brain anatomy, with spatial resolution on the order of 1 mm3, and is widely used to characterize neuropathological conditions in clinical practice. MRS allows the detection of signals from certain drugs and from a limited number of endogenous neurochemicals, with spatial resolution on the order of 1 cm3, depending upon the compound under investigation. fMRI refers to a family of methods for obtaining brain images which are sensitive to changes in cerebral metabolism with spatial resolution on the order of a few millimeters and temporal resolution of a few seconds. MRI, MRS, and fMRI rely on the same basic principles and, at least for human studies, generally use the same hardware. Although the technology is evolving rapidly, there are currently more than 1000 installed 1.5 Tesla (T) MR scanners in the United States which are capable of performing some or all of these methodologies. Thus, this technology is widely disseminated and available to investigators at a number of clinical research sites. This review will describe the basic principles of MRI, MRS, and fMRI. With this information as background, the literature on the use of MR in substance abuse research is reviewed in Chapter 6.