Cerebral blood flow: measurement with xenon-enhanced dynamic helical CT.

Abstract

To improve CT number reproducibility in helical CT, a newly developed controlled-orbit helical scan mechanism was applied. The authors developed a method for volumetric measurement of cerebral blood flow (CBF) with dynamic helical computed tomography (CT) after inhalation of xenon gas. In three subjects (two healthy men aged 22 and 38 years and a 7-year-old girl with moyamoya disease), six helical scans were obtained during 6-minute xenon inhalation, and CT scans with 41 sections in 2-mm increments were reconstructed from each scan. Conventional CBF calculation was then applied to the CT images. CBF maps of 40 sections for each subject of sufficient diagnostic quality were obtained with a 39-cGy radiation dose. The spatial resolution was 2.5 line pairs per centimeter. This volumetric CBF mapping method is applicable in clinical practice because of the short examination time and acceptable radiation dose.