Efficacy of 1.5 Harmonic Imaging for Intravenous Myocardial Contrast Echocardiography

Abstract

Background. Although second harmonic (2H) imaging is utilized to minimize the tissue signals in myocardial contrast echocardiography (MCE), the native tissue harmonic signal is sufficiently high enough to cause a misreading of myocardial opacification when high mechanical index (MI) is used.Purpose. The backscattered signal from microbubbles at high MI is broadband, while it is narrowband at low MI.Therefore, the bubble/tissue signal ratio is expected to be high between the fundamental signal and 2H frequencies at high MI. Our aim was to elucidate the efficacy of a new imaging method using an in-between frequency, denoted as 1.5 harmonic (1.5H) imaging.Methods. Six open-chest dogs were examined using Toshiba APLIO with 1.5H and conventional 2H system. The transmitting/receiving frequencies were 2.3/3.3 MHz for 1.5H and 1.4/2.8MHz for 2H imaging, respectively.Intermittent MCE was performed at a MI of 1.6 after injection of Levovist , and baseline intensity and peak intensity of opacification of the ventricular septum were measured.Results. While baseline intensity of the septum was significantly lower using 1.5H than 2H (26 4 vs. 43 14 gray level, p<0.001), the opacification after Levovist was significantly higher using 1.5H than 2H (91 32 vs. 51 38, p<0.001). Due to the combination of these effects, visual recognition of myocardial opacification was quite superior with 1.5H imaging.Conclusion. The 1.5H imaging system provides superb contrast opacification when using high MI. (J Echocardiogr 2005; 3: 104-108)

Coronary Tree Assessed With Contrast Harmonic Imaging

“…Recently, several advanced harmonic imagings that use high or sub-harmonics have emerged as new harmonic technologies. These new imaging technologies will overcome a problem of far-field attenuation and bring us marked improvement of signal to noise ratio [26]. In this study, we did not measure direct blood velocity of capillary, arteriole and small artery using Doppler signal.…”

Promising Therapeutic Effects of Cell Sheet Implantation with a Pedicle Omentum Flap to Enhance the Angiogenic Response to Ischemic Cardiomyopathy

“…Blood perfusion analysis by performing myocardial contrast echocardiography: A myocardial contrast echocardiography (MCE) examination was performed by using Sonazoid (Daiichi-sankyo, Tokyo, Japan) as the contrast agent as described previously [11][12][13]. LV short axis images at the mid-LV level (clearly depicting the base of the papillary muscles) were obtained just before and 8 weeks after the treatment by using an ultrasonographic scanner (Aplio).…”

Feasibility of Clinical Application of Ultrasound Molecular Imaging

“…Until now, several techniques that detect the bubble signal efficiently with multiple ultrasound pulses have been developed, including pulse inversion, power pulse inversion, power modulation, coherent contrast imaging and cadence pulse sequencing (Table 4). Forsberg et al, 2000 1.5 harmonic imaging Toshida et al, 2005 Ultraharmonic imaging Kuersten et al, 2001 Harmonic power Doppler Heinle et al, 2000 Low MI imaging techniques (for real-time observation)…”