kVp Scan Research Articles

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.

The principles of shop manipulation for engineering apprentices

We aimed to determine whether 80 kVp conventional nonenhanced head CT scans have better gray–white matter contrast than standard 120 kVp scans performed on the same patients. Thirty head CT scans acquired at 80 kVp (CT dose index [CTDI]vol 46) were compared to prior studies in the same patients performed at 120 kVp (CTDIvol 59). Signal (Hounsfield units [HU]), noise (sd HU), and contrast-to-noise ratio per dose (CNRD) were assessed in multiple cerebral gray and white matter regions of interest. A noise correction factor was used to compensate for scanning at different CTDIvol values. Average gray matter signal at 80 kVp and 120 kVP was 33.9 ± 3.5 HU and 29 ± 4.6 HU, respectively (p < 0.0001); the averages for white matter were 22.5 ± 3.1 HU and 21.6 ± 4.6 HU, respectively (p = 0.11). Corrected noise was 3 ± 0.6 and 2.7 ± 0.6, respectively, for gray matter (p = 0.0001), and 2.8 ± 0.6 and 2.6 ± 0.5, respectively, for white matter (p = 0.00001). The gray–white matter CNRD was 4.0 ± 1.2 at 80 kVp and 2.8 ± 1 at 120 kVp (p < 0.00001). Cerebral gray–white matter CNRD is increased by 40% at 80 kVp compared to conventional 120 kVp CT scans. These findings justify further clinical evaluation in the acute stroke setting.