著者

原田 耕平 千葉 彩佳 溝延 数房 沼澤 香夏子 今井 達也

出版者

公益社団法人 日本放射線技術学会

雑誌

日本放射線技術学会雑誌 (ISSN:03694305)

巻号頁・発行日

vol.72, no.11, pp.1098-1104, 2016 (Released:2016-11-20)

参考文献数

12

被引用文献数

1

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Preoperative three-dimensional computed tomography (3DCT) of the liver is the most important examination in performing preoperative simulation. Detailed visualization of the portal vein using the workstation is critical to enable accurate liver segmentation. However, the timing of imaging in the portal venous phase has mostly been reported equivalent to that of the liver screening examinations commonly performed. The purpose of this study was to examine the optimal timing of image capture to create the best portal vein visualization in preoperative 3DCT of the liver. Seventy-nine patients who underwent hepatectomy for malignant liver tumors were enrolled in this study. All patients were preoperatively examined using protocol A (imaging method separated into a portal venous phase and a hepatic venous phase) and then examined 1 week after surgery using protocol B (normal liver screening protocol). We first established the regions of interest in the portal vein and the hepatic vein and then compared CT values for these regions under protocol A and protocol B. The average CT value of the portal vein in protocol A and B was 239.8±28.1 HU and 202.2±18.5 HU, respectively. The average CT value of the portal vein in protocol A was significantly higher compared with protocol B (p<0.01). By introducing separate timing for portal venous phase imaging before preoperative 3DCT (protocol A), it is possible to satisfactorily depict the portal vein.

著者

堀尾 一樹 磯田 豊 小林 直人 千葉 彩

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.70, no.1, pp.41-62, 2020-08-24

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If there is the coastal upwelling, it is common to think that the upward advection of cold deep water will make the coastal side cooler than the offshore side. Shelf slope upwelling (SSU) presented in this study, however, occurs only when the shallow coastal side is rather warm due to a continuous sea surface heating in summer. The present study investigated the formation process of such SSU using a numerical model driven by surface heating. From the results of examining unsteady state of heat budget and dynamic balance, SSU was found to be a kind of compensation flow, not the bottom Ekman flow. That is, to satisfy continuity in a vertical section, the offshore flow caused by the horizontal density/temperature gradient was supplemented by the shoreward flow strongly confined to the sloping seabed. This SSU will probably be one of the important flows contributing to material transport, e.g., unused nutrients and anoxic water etc., from deep to near coast in summer, while it is difficult to prove the existence of SSU even indirectly from the observed water temperature.