The NMR revolution in brain imaging

Nuclear magnetic resonance (NMR) technology is accelerating a revolution in medical and scientific neuroimaging that began in the 1970s with the introduction of powerful new x ray methods—computed tomography, positron emission tomography, and single photon emission computed tomography. Refinement of these technologies continues as applications for which they are uniquely well suited are defined.

Most clinicians are familiar with magnetic resonance imaging, which has recently become the most generally useful imaging modality for medical diagnosis.1 But conventional magnetic resonance imaging is only the first of an array of methods that will eventually comprise the NMR diagnostic armamentarium. We use the generic term “nuclear magnetic resonance” to emphasise the versatility of the technology. New NMR methods are in various stages of implementation and, combined with conventional magnetic resonance imaging, they are on the verge of changing medical practice so extensively that to describe the process as a revolution may ultimately seem conservative.

NMR technology differs fundamentally from x ray methods. It uses the magnetic properties of atomic nuclei that occur naturally in the body; mostly hydrogen (¹H) in water and other molecules, although several other nuclei, including phosphorus (³¹P), carbon (¹³C), lithium (⁷Li), sodium (²³Na), nitrogen (¹⁵N), and oxygen (¹⁷O), are in regular use for medical research, and diagnostic applications are on the horizon.2

As measurements are made by synchronising atomic nuclear signals already present in tissue, NMR methods are among the least invasive diagnostic techniques available.3 At …