Functional magnetic resonance imaging: Clinical applications and potential

Demonstration that contrast in magnetic resonance images can be generated b ased on differences in blood oxygenation has led to an explosion of interes t in so-called functional magnetic resonance imaging (FMRI). FMRI can be us ed to map increases in blood flow that accompany local synaptic activity in the brain. The technique has proved remarkably sensitive and has been used to map a broad range of cognitive, motor and sensory processes in the brai n entirely non-invasively. More recently, efforts have been made to extend this technique to the analysis of clinical problems. A major application is for presurgical localization of cerebral functions, e.g. in the surgical t reatment of epilepsy. The technique also is beginning to provide informatio n on functional consequences of abnormal brain development. Perhaps most ex citing are applications to neurological impairments that are not associated with structural abnormalities, such as learning problems, dyslexia and mov ement disorders. It is possible that useful applications of FMRI may be fou nd for directly mapping sites of action of CNS-active drugs. Although the e xtent of the potential clinical applications of this new brain mapping tech nique is not clear, the widespread availability of MRI scanners suggests th at the technique should in some form soon become a routine tool in major ne uroradiological centres.