Cerebral Size Affects Localized Density Measured by Computed Tomography

To the Editor.—  Pearlson et al,¹ in the August 1989 issue of the Archives, reported that larger overall brain area was associated with lower computed tomographic density in schizophrenic and control individuals, replicating a similar finding by Jernigan et al.² We herein report³ that this inverse correlation holds true for certain, but not all, cerebral regions of interest (ROIs). We conclude that studies attempting to associate behavior with cerebral density should control for this sizedensity relationship.

Patients and Methods.—  Fifty-six psychiatrically screened subjects with clinically normal computed tomographic (CT) scans were included in this study. Age ranged from 18 to 73 years, with 31 men and 25 women. Scans were performed on a GE 8800 scanner (General Electric Medical Systems, Milwaukee, Wis), and ROI measurements were performed independently on two separate occasions by a radiologist. Regions of interest included both left and right frontal gray, frontal