Analysis of the dense lesion at computed tomography with dual kVp scans.

By scanning the brain first at 100 and then at 140 kVp one can distinguish, in vivo, between blood and calcium or iodine solutions. The higher atomic number of calcium or iodine causes their CT values to decrease significantly while blood shows no significant change. This principle was applied to eight patients with hemorrhages, calcified lesions, or iodine-contrast augmented lesions. Hemorrhages showed no significant change with change in kVp, while the lesions containing calcium or iodine showed a highly significant change. This is a useful maneuver for determining the nature of a high-value lesion.