FIG 1. Four cerebral CT sections through the basal nuclei obtained at 200 mAs and at 80 kVp (C, D) and 120 kVp (A, B), before (A, C) and after (B, D) IV administration of iodinated contrast material (C, 80 kVp [number 2], A, 120 kVp [number 1], D, 80 kVp + C [number 4], B, 120 kVp + C [number 3]). ROIs were drawn on cortical gray matter, basal nuclei gray matter, and white matter. Typical ROIs chosen for measurements are shown on A. The four sections are displayed with the same window settings (window level: 40 HU, and window width: 80 HU). At 80 kVp, the contrast enhancement is increased, as well as the gray matter-white matter contrast. The signal-to-noise ratio is not significantly altered