著者
Sakyo Hirai Hirotaka Sato Toshihiro Yamamura Koichi Kato Mariko Ishikawa Hirotaka Sagawa Jiro Aoyama Shoko Fujii Kyohei Fujita Toshinari Arai Kazutaka Sumita
出版者
The Japanese Society for Neuroendovascular Therapy
雑誌
Journal of Neuroendovascular Therapy (ISSN:18824072)
巻号頁・発行日
pp.oa.2022-0026, (Released:2022-07-30)
参考文献数
29

Objective: CT perfusion (CTP) provides various hemodynamic parameters. However, it is unclear which CTP parameters are useful in predicting clinical outcome in patients with acute ischemic stroke (AIS).Methods: Between February 2019 and June 2021, patients with anterior circulation large-vessel occlusion who achieved successful recanalization within 8 hours after stroke onset were included. The relative CTP parameter values analyzed by the reformulated singular value decomposition (SVD) method in the affected middle cerebral artery territories compared to those in the unaffected side were calculated. In addition, the ischemic core volume (ICV) was evaluated using a Bayesian Vitrea. The final infarct volume (FIV) was assessed by 24-hour MRI. The correlation between these CTP-derived values and clinical outcome was assessed.Results: Forty-two patients were analyzed. Among the CTP-related parameters, the ICV, relative cerebral blood volume (rCBV), and relative mean transit time (rMTT) showed a strong correlation with the FIV (ρ = 0.74, p <0.0001; ρ = −0.67, p <0.0001; and ρ = −0.66, p <0.0001, respectively). In multivariate analysis, rCBV, rMTT, and ICV were significantly associated with good functional outcome, which was defined as a modified Rankin Scale score ≤2 (OR, 6.87 [95% CI, 1.20–39.30], p = 0.0303; OR, 11.27 [95% CI, 0.97–130.94], p = 0.0269; and OR, 36.22 [95% CI, 2.78–471.18], p = 0.0061, respectively).Conclusions: Among the CTP parameters analyzed by the SVD deconvolution algorithms, rCBV and rMTT could be useful imaging predictors of response to recanalization in patients with AIS, and the performances of these variables were similar to that of the ICV calculated by the Bayesian Vitrea.
著者
Kazuto Takemura Yoshihiro Nakae Yoshihisa Fujihara Hirotaka Sato Hitoshi Sato Atsushi Goto Hiroaki Naoe
出版者
公益社団法人 日本気象学会
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
vol.18A, no.Special_Edition, pp.21-26, 2022 (Released:2022-09-21)
参考文献数
17

Several regions in western Japan experienced a record-breaking early onset of the rainy season called Baiu in mid-May 2021, which is attributed to the northward movement and enhancement of the Baiu frontal zone. This study investigates large-scale atmospheric circulation that contributes to the early onset of Baiu. Diagnostic and statistical analyses based on reanalysis datasets reveal that both enhanced convection over the western Indian Ocean associated with the Madden–Julian oscillation and a blocking high near western Russia promote the excitation of Rossby waves to propagate downstream along the upper-tropospheric jet, and thus contributing to the northward movement of the Baiu frontal zone. The anomalous convection over the western Indian Ocean and the subtropical western North Pacific also may affect anticyclonic circulation anomalies to the northeast of the Philippines in the lower troposphere, which promotes moisture inflow toward western Japan and consequently intensifies the Baiu frontal zone. Numerical and quantitative analyses of the circulation anomalies near Japan based on a linear baroclinic model confirm the aforementioned results. The results indicate that the anomalous convection over the Asian monsoon region and the blocking high near western Russia are the primary factors contributing to the early onset of Baiu.
著者
Kazuto Takemura Yoshihiro Nakae Yoshihisa Fujihara Hirotaka Sato Hitoshi Sato Atsushi Goto Hiroaki Naoe
出版者
公益社団法人 日本気象学会
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
pp.18A-004, (Released:2022-08-18)

Several regions in western Japan experienced a record-breaking early onset of the rainy season called Baiu in mid-May 2021, which is attributed to the northward movement and enhancement of the Baiu frontal zone. This study investigates large-scale atmospheric circulation that contributes to the early onset of Baiu. Diagnostic and statistical analyses based on reanalysis datasets reveal that both enhanced convection over the western Indian Ocean associated with the Madden–Julian oscillation and a blocking high near western Russia promotes the excitation of Rossby waves to propagate downstream along the upper-tropospheric jet, and thus contributing to the northward movement of the Baiu frontal zone. The anomalous convection over the western Indian Ocean and the subtropical western North Pacific also may affect anticyclonic circulation anomalies to the northeast of the Philippines in the lower troposphere, which promotes moisture inflow toward western Japan and consequently intensifies the Baiu frontal zone. Numerical and quantitative analyses of the circulation anomalies near Japan based on a linear baroclinic model confirms the aforementioned results. The results indicate that the anomalous convection over the Asian monsoon region and the blocking high near western Russia are the primary factors contributing to the early onset of Baiu.