K Nambu1, R Suzuki, K Hirakawa. 1. Medical Systems Engineering Department II, Toshiba Corporation, Tochigi, Japan.
Abstract
PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: This volumetric CBF mapping method is applicable in clinical practice because of the short examination time and acceptable radiation dose.
PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: This volumetric CBF mapping method is applicable in clinical practice because of the short examination time and acceptable radiation dose.