Hiroyuki Sugimori1, Noriyuki Fujima2, Yuriko Suzuki3, Hiroyuki Hamaguchi4, Motomichi Sakata5, Kohsuke Kudo6. 1. Department of Radiological Technology, Hokkaido University Hospital, North-14, West-5, Kita-ku, Sapporo, Hokkaido, Japan 060-8648. Electronic address: sugimori@huhp.hokudai.ac.jp. 2. Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, North-15, West-7, Kita-ku, Sapporo, Hokkaido, Japan 060-8638. Electronic address: fujima@med.hokudai.ac.jp. 3. Philips Electronics Japan, 2-13-37 Kohnan, Minato-Ku, Tokyo, Japan, 108-8507. Electronic address: yuriko.suzuki@philips.com. 4. Department of Radiological Technology, Hokkaido University Hospital, North-14, West-5, Kita-ku, Sapporo, Hokkaido, Japan 060-8648. Electronic address: hhummer@huhp.hokudai.ac.jp. 5. Graduate School of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo, Hokkaido, Japan 060-0812. Electronic address: moto@hs.hokudai.ac.jp. 6. Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, North-15, West-7, Kita-ku, Sapporo, Hokkaido, Japan 060-8638. Electronic address: kkudo@huhp.hokudai.ac.jp.
Abstract
PURPOSE: Arterial spin labeling (ASL) methods have been widely used for evaluation of cerebral blood flow (CBF) by magnetic resonance imaging. However, ASL methods require setting of the post labeling delay (PLD) time for obtaining images. As the hemodynamic status cannot be estimated in each patient, the resultant quantitative values of blood flow may not be accurate. The multi-phase pseudo continuous arterial spin labeling (pCASL) method can be used to obtain images at various time-points. The purpose of this study was to create the transit-time maps for correcting the delayed blood flow and evaluate CBF using the transit-time maps obtained by the multi-phase pCASL method. MATERIALS AND METHODS: Twelve patients who underwent both 3.0-tesla magnetic resonance imaging (MRI) and single photon emission computed tomography with iodine-123-N-isopropyl-p-iodoamphetamine (123I-IMP) were investigated. This study was approved by the institutional review board of our institution. MRI acquisitions included PLD time-fixed (1525ms) and multi-phase pCASL sequences. The transit-time maps were calculated from multi-phase pCASL images by software. The transit-time maps were applied to PLD-fixed pCASL images pixel by pixel, for calculating the CBF value corrected for peak blood transit time. Regions of interest were drawn on the brain. IMP-CBF, ASL-CBF (default and corrected) and transit time were measured for each segment. RESULTS: Twelve patients and 264 segments were investigated. The mean IMP-CBF, ASL-CBF (default, corrected) and transit time were 28.4, 23.0, 29.6, [ml/min/100g] and 1977.5 [ms], respectively. There were no significant differences between IMP-CBF and ASL-CBF (corrected). CONCLUSION: CBF values can be corrected by using the transit-time maps obtained using the multi-phase pCASL method.
PURPOSE: Arterial spin labeling (ASL) methods have been widely used for evaluation of cerebral blood flow (CBF) by magnetic resonance imaging. However, ASL methods require setting of the post labeling delay (PLD) time for obtaining images. As the hemodynamic status cannot be estimated in each patient, the resultant quantitative values of blood flow may not be accurate. The multi-phase pseudo continuous arterial spin labeling (pCASL) method can be used to obtain images at various time-points. The purpose of this study was to create the transit-time maps for correcting the delayed blood flow and evaluate CBF using the transit-time maps obtained by the multi-phase pCASL method. MATERIALS AND METHODS: Twelve patients who underwent both 3.0-tesla magnetic resonance imaging (MRI) and single photon emission computed tomography with iodine-123-N-isopropyl-p-iodoamphetamine (123I-IMP) were investigated. This study was approved by the institutional review board of our institution. MRI acquisitions included PLD time-fixed (1525ms) and multi-phase pCASL sequences. The transit-time maps were calculated from multi-phase pCASL images by software. The transit-time maps were applied to PLD-fixed pCASL images pixel by pixel, for calculating the CBF value corrected for peak blood transit time. Regions of interest were drawn on the brain. IMP-CBF, ASL-CBF (default and corrected) and transit time were measured for each segment. RESULTS: Twelve patients and 264 segments were investigated. The mean IMP-CBF, ASL-CBF (default, corrected) and transit time were 28.4, 23.0, 29.6, [ml/min/100g] and 1977.5 [ms], respectively. There were no significant differences between IMP-CBF and ASL-CBF (corrected). CONCLUSION: CBF values can be corrected by using the transit-time maps obtained using the multi-phase pCASL method.