A novel index to estimate the corpus callosum morphometry in adults: callosal/supratentorial-supracallosal area ratio.

PURPOSE To prospectively investigate the feasibility of a new index (callosal/supratentorial-supracallosal area ratio) in morphometric analysis of the corpus callosum in adults. MATERIALS AND METHODS The callosal and supratentorial-supracallosal areas of 50 healthy volunteers were measured on T1 weighted midsagittal magnetic resonance images. Mean value and variation coefficient for the index was calculated. In a limited subset of subjects (n=25), an interobserver agreement study was conducted to estimate the reproducibility of the index. RESULTS There was a statistically significant difference between the area for corpus callosum and supratentorial-supracallosal regions in males and females, although the calculated ratio (index) had no sex-difference. When compared to the literature, the variation coefficient was relatively lower (12.0%), with good interobserver agreement (Pearson correlation analysis, r=0.83). CONCLUSION Callosal/supratentorial-supracallosal area ratio might serve as a reliable index in morphometric analysis of the corpus callosum in adults.