NIMH report. Update on brain imaging.

Abstract

Magnetic resonance imaging (MRI) MRI uses a magnetic field that permits detection of the frequen cies at which chemical elements in body tissue resonate. The char acteristic frequencies of various brain tissues are recorded to cre ate an exquisitely detailed picture of brain structures. MRI offers important advan tages over CT for imaging brain structures. Besides providing much clearer pictures, it is more flex ible, allowing researchers to study the distribution of a wide variety of substances in the brain. Fur then, MRI does not require the use of ionizing radiation. Richard Suddath, M.D., and his colleagues (4) at the NIMH clini cal brain disorders branch have used MRI to compare the volume of brain tissue in the prefrontal cortex and temporal lobes of schizo phrenic patients and controls matched for age and sex. They found no differences in white mat ten or in prefrontal gray matter, but did find a 20 percent reduc tion in gray matter in the tempo ral lobes of schizophrenic patients. Further, the reduction in temporal gray matter is inversely correlated with lateral ventricular volume. This finding suggests a relation ship between ventricular enlarge ment and the reduction in gray matter. When or why the reduc tion in gray matter occurs is not yet known.