小林 春香, 別府 慎太郎, 石蔵 文信, 上田 宏昭, 松下 恵介, 柏木 寧, 矢倉 佐知子, 浜田 聡明

Haruka KOBAYASHI, Shintaro BEPPU, Fuminobu ISHIKURA, Hiroaki UEDA, Keisuke MATSUSHITA, Yasushi KASHIWAGI, Sachiko YAGURA, Toshiaki HAMADA

大阪大学医学部保健学科

School of Allied Health Sciences Osaka University Faculty of Medicine

キーワード : Contrast media, Echocardiography (contrast), Harmonic (second), Power (acoustic)

Background. Although Optison (FS-69) is commercially available in the United States, the optimal setup of ultrasonic equipment for myocardial contrast echocardiography has yet to be elucidated. Here we examin the optimal setting for adequate opacification of the myocardium. Method. Optison (0.1 ml) was administered intravenously during recording of the short axis view of the left ventricle using the Toshiba prototype echocardiograph in 11 open-chest beagles. Myocardial opacification was evaluated by calculating the baseline-subtracted peak video intensity (256 gray scale) at four regions of the left ventricular wall: the anterior, lateral, posterior, and septal walls. We examined the fundamental (3.75 MHz) and second harmonic (2.5/5.0 MHz) imaging during both continuous and intermittent (one pulse per cardiac cycle) mode. Acoustic power (AP) decreased in steps of 1.5 dB from maximal mechanical index (1.4). We also examined the effect of the distance between the transducer and the heart by placing an ultrasonic spacer with a width of 1 cm or 3 cm.
Results. Myocardial opacification was hardly recognized by the continuous mode; however, the intermittent mode provided sufficient opacification in either the fundamental or harmonic mode. Excessive acoustic power did not improve myocardial opacification. The influence of high acoustic power was significant in the field near the transducer.
Conclusion. The left ventricular myocardium is clearly opacified by venous administration of Optison when the mechanical settings of the ultrasonic equipment are appropriate.