| Japanese |
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| Title | 超音波ドプラ法による超音波入射角度に依存しない絶対流速測定法 |
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| Subtitle | 原著 |
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| Authors | 赤松繁*, 近藤祐司**, 土肥修司* |
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| Organization | *岐阜大学医学部麻酔・蘇生学教室, **アロカ株式会社第1技術部 |
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| Journal | 循環制御 |
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| Volume | 17 |
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| Number | 3 |
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| Page | 379-385 |
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| Year/Month | 1996/ |
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| Article | 原著 |
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| Publisher | 日本循環制御医学会 |
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| Abstract | 「要旨」超音波ドプラ法を用いた連続的心拍出量モニターの試みでは, 血流速度測定における血流方向に対する超音波ビームの入射角が誤差要因となり心拍出量の正確な測定を妨げている. 超音波ドプラ法によって測定される血流速度は, 超音波ビームに対する血流の相対的流速であり超音波入射角に依存する血流速度である. そこで, 超音波入射角度に依存しない絶対血流速度の測定のため, 極小超音波振動子を二個組み合わせた新しいドプラプローブを作製した. 絶対流速(V)は, 二つの超音波振動子によって測定される流速(V1, V2)からV=((V1)2+(V2)2)1/2として求めた. 流速の演算には新たに開発した位相差分法を用い, 超音波入射角に依存しない絶対流速をリアルタイムに測定することを試みた. 水槽実験において, 灌流モデル内の管壁に水流方向に対し平行に留置したドプラプローブで流速測定を行い, 続いてドプラプローブの水流方向に対する入射角を9°, 18°に設定して流速測定を行い, 測定された流速を比較検討した. ドプラプローブを管壁に水流方向に対して平行に留置して測定した流速と, プローブの水流方向に対する入射角を9°, 18°に変え測定した流速の間には各々r2=0.99の良好な相関関係を認めた. 超音波振動子を2個綿み合わせた新しい流速測定法により超音波入射角に依存しない絶対流速が測定可能であると思われた. 本法による流速測定によって超音波ドプラ法による連続的心拍出量モニターの開発が期待される. |
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| Practice | 基礎医学・関連科学 |
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| Keywords | Cardiac output, Doppler, Monitoring, Ultrasound, Velocity measurement |
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| English |
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| Title | Velocity Measurement Using a Newly Developed Doppler Catheter Iindependent of the Angle of Incidence |
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| Authors | Shigeru Akamatsu, Yuji Kondo*, Shuji Dohi |
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| Organization | Department of Anesthesiology and Critical Care Medicine, Gifu University School of Medicine, *Aloka Co. Ltd. |
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| Journal | Circulation Control |
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| Volume | 17 |
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| Number | 3 |
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| Page | 379-385 |
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| Year/Month | 1996/ |
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| Article | Original article |
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| Publisher | Japan Society of Circulation Control |
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| Abstract | Flow velocity measured by Doppler ultrasound is influenced by the angle of incidence between the direction of flow and that of ultrasound. The angle of incidence often constitutes an error in velocity measurements with Doppler ultrasound. We newly developed a Doppler catheter to obtain the true velocity independent of the angle formed by the ultrasound beam and the flow. The Doppler catheter has a pair of adjoining ultrasonic crystals located on the side of the catheter in right angle. The Doppler shifts (△f1, △f2) were detected by two transducers, respectively, sampling at closely spaced two points. The values of Δf1 and Δf2 were used to compute two velocity measurements and the true velocity was calculated using following equation：V=((V1)2+(V2)2)1/2, where V=true velocity, V1 and V2=velocity detected by the transducer 1 and 2. A continuous flow model was set up, and an electromagnetic flow probe and a Doppler catheter were placed into the circuit. The flow velocity was measured by the Doppler catheter placed parallel to the flow direction. Then, the incident angles were created in 9° and 18°, bending the distal portion of the catheter. The flow velocities measured in different incident angles (V9, V18) were compared to the flow velocity measured with the catheter parallel to the flow direction (Ve). The velocities were calculated using newly developed phase differential techniques from measured Doppler shifts. V9 correlated with Ve (r2=0.99, p<0.001), and V18 also correlated with Ve (r2=0.99, p<0.001). Our new Doppler catheter incorporating a pair of transducers positioned at a fixed angle enables us to measure true flow velocity independent of the ultrasonic beam's angle of incidence. Clinical application of our technique and the Doppler catheter would include the continuous measurements of blood flow velocity in great vessels, e. g., pulmonary artery, and a continuous monitoring of cardiac output. (Circ Cont 17：379〜385, 1996) |
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| Practice | Basic medicine |
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| Keywords | Cardiac output, Doppler, Monitoring, Ultrasound, Velocity measurement |
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