| 特集名 | 肝の画像診断 | |
|---|---|---|
| 題名 | 超音波 (6) 新しい超音波造影剤 | |
| 発刊年月 | 2002年 01月 | |
| 著者 | 森安 史典 | 東京医科大学第4内科 |
| 著者 | 飯島 尋子 | 東京医科大学第4内科 |
| 【 要旨 】 | Levovist(R)は高音圧系の造影剤であり，次世代の新しい造影剤は低音圧系の造影剤ということができる．前者は高い音圧で気泡を崩壊せしめ，その際の信号を映像化するため，subtraction法を中心とした手法が組織からの信号を除去でき有用である． 一方，低音圧系の造影剤は，低音圧で気泡を振るわせて継続的に非線形信号を取り出す手法が中心となるが，同時に低音圧のためにtissue harmonic成分の発生が少ないので，感度の良い，持続的なperfusionイメージを得ることができる．位相を反転したパルス波を使うpulse inversion harmonic imagingを中心とした手法がこのために用いられるが，さらに，振るえる気泡からの信号に感度の高い手法が開発され応用されつつある． |
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| Theme | Imaging Diagnostics of Liver Disease | |
|---|---|---|
| Title | Novel Ultrasound Contrast Agents | |
| Author | Fuminori Moriyasu | Department of Internal Medicine, Tokyo Medical University |
| Author | Hiroko Iijima | Department of Internal Medicine, Tokyo Medical University |
| [ Summary ] | Levovist(R) is a "high MI agent" and the new next generation agents are low MI ones. The signal from the former type agents is produced by destruction of microbubbles with high MI acoustic pressure and other methods, mainly using subtraction techniques through reduction of tissue signals. On the other hand, non signals can be continuously obtained by vibrating microbubbles with low acoustic pressure, as in the case of the low MI agents. Real time perfusion imaging with a high sensitivity is possible because of decreased tissue harmonic components. A method using an inverted pulse, such as pulse inversion harmonic imaging, is used for these agents. Recently, new techniques in which a higher sensitivity can be obtained from vibrating microbubbles have been developed and applied to clinical settings. |
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