Daisuke Oura1, Masahito Kawabori2,3, Yoshimasa Niiya4, Motoyuki Iwasaki4, Shinpei Satoh1, Takumi Yokohama1, Shoji Mabuchi4, Kiyohiro Houkin3. 1. Department of Radiology, Otaru General Hospital, Otaru, Japan. 2. Department of Neurosurgery, Otaru General Hospital, Otaru, Japan - masahitokawabori@yahoo.co.jp. 3. Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan. 4. Department of Neurosurgery, Otaru General Hospital, Otaru, Japan.
Abstract
BACKGROUND: Recent clinical trials demonstrated the efficacy of thrombectomy for ischemic stroke against acute large vessel occlusion (LVO). To overcome the problem with excessive examination time for diagnosis of cerebral perfusion and/or the use of contrast agent to determine penumbra, we adopted a new magnetic resonance imaging technique named Acute Stroke Assessment using rapid Pseudo-continuous arterial spin labeling (ASAP-ASL) method. METHODS: The study included healthy volunteers and clinical patients. The signal to noise ratio (SNR) and acquisition time were compared with various numbers of signal average (NSA) of rapid pseudo-continuous arterial spin labeling (pCASL) using the 10-mm thick slice width and narrow scan range focusing the level of basal ganglia by healthy volunteers. After applying clinically acceptable protocol for ASAP-ASL, we then checked image qualities and an accuracy of the method by comparing with the angiographical imaging obtained from the clinical patients regarding the degree of consistency. RESULTS: NSA were compared between two and fourteen, and 10 NSA was decided to be introduced for clinical use (1 minutes and 17 second) for obtaining clinically acceptable image, which was shorter than the time required for ordinary whole brain pCASL (approximately 5 minutes). In the clinical study, the occlusion site estimated by ASAP-ASL showed high correlation with that of digital subtraction angiography (κ = 0.63-0.79). CONCLUSIONS: ASAP-ASL method requires approximately one minutes to obtain clinically relevant brain perfusion imaging which can successfully identify ischemic region in LVO patients.
BACKGROUND: Recent clinical trials demonstrated the efficacy of thrombectomy for ischemic stroke against acute large vessel occlusion (LVO). To overcome the problem with excessive examination time for diagnosis of cerebral perfusion and/or the use of contrast agent to determine penumbra, we adopted a new magnetic resonance imaging technique named Acute Stroke Assessment using rapid Pseudo-continuous arterial spin labeling (ASAP-ASL) method. METHODS: The study included healthy volunteers and clinical patients. The signal to noise ratio (SNR) and acquisition time were compared with various numbers of signal average (NSA) of rapid pseudo-continuous arterial spin labeling (pCASL) using the 10-mm thick slice width and narrow scan range focusing the level of basal ganglia by healthy volunteers. After applying clinically acceptable protocol for ASAP-ASL, we then checked image qualities and an accuracy of the method by comparing with the angiographical imaging obtained from the clinical patients regarding the degree of consistency. RESULTS: NSA were compared between two and fourteen, and 10 NSA was decided to be introduced for clinical use (1 minutes and 17 second) for obtaining clinically acceptable image, which was shorter than the time required for ordinary whole brain pCASL (approximately 5 minutes). In the clinical study, the occlusion site estimated by ASAP-ASL showed high correlation with that of digital subtraction angiography (κ = 0.63-0.79). CONCLUSIONS:ASAP-ASL method requires approximately one minutes to obtain clinically relevant brain perfusion imaging which can successfully identify ischemic region in LVO patients.