Three-dimensional surface rendering in MRI morphometry: a study of the planum temporale

The emergence of methodologies for accurately rendering cortical surfaces suggests possible quantitative applications of surface rendering to morphometry of the cerebral cortex. We examined this novel use of surface renderings in a study of the planum temporale, a neuroanatomical structure exhibiting well-documented normal asymmetry previously visible only in postmortem studies. With the aid of three-dimensional renderings of the supratemporal cortex, the area of the planum temporal was analyzed in the volume MRIs of seven normal, strongly right-handed males. In comparison with areas derived from conventional measurements of serial MRI sections, planum temporale areas derived from supratemporal surface renderings offered far greater interrater reliability, and presumably improved validity as reflected by more consistent evidence of the anticipated planum asymmetry. Morphometry of the supratemporal cortex is enhanced by the use of three-dimensional surface renderings. Application of surface-rendering techniques to morphometry of other cortical regions is discussed.