Effect of Pulse Shaping on Subharmonic Aided Pressure Estimation In Vitro and In Vivo.
Effect of Pulse Shaping on Subharmonic Aided Pressure Estimation In Vitro and In Vivo.
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DOI：
10.7863/ultra.15.11106
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发表时间：
2017-01
期刊：
影响因子：
--
通讯作者：
Forsberg F
中科院分区：
文献类型：
--
作者：
Gupta I;Eisenbrey J;Stanczak M;Sridharan A;Dave JK;Liu JB;Hazard C;Wang X;Wang P;Li H;Wallace K;Forsberg F
亚谐成像(SHI)是一种利用微泡在高压超声作用下的非线性振荡，以基频fo发射，以发射频率fo/2接收的技术。亚谐辅助压力估计(SHAPE)是基于微泡的亚谐振幅与环境压力变化之间的逆关系。针对SHAPE研究最敏感的声功率，对8个不同包络的波形进行了优化。这项研究采用四个输入传输周期，首先在体外，然后在三只犬体内进行，以选择获得最佳灵敏度的波形，以使用SHAPE检测门静脉压力的变化。使用具有4C曲线线阵的Logiq 9扫描仪采集2.5 MHz射频数据。扫描采用双成像模式，B型成像频率为4 MHz，SHI对比模式发射频率为2.5 MHz，接收频率为1.25 MHz。本研究以全氟丁烷的脂质稳定气泡索那唑为造影剂。在体外，所有波形(r从−0.77到−0.93；p<；0.001)的亚谐振幅随压力的增加呈线性下降。在体外和体内的结果中，与窄带脉冲相比，宽带脉冲的形状梯度与压力变化的相关性显著更高。相关系数最高的是高斯加窗二项式滤波方波，其r值为−0.95。3只犬中有1只因技术原因被淘汰，另外2只与体外实验结果非常相似(r从−0.72到−0.98；p<；0.01)。在活体实验中，采用高斯加窗二项式滤波方波获得了最一致的结果(r=−0.95和−0.96)。总之，使用该波形是对现有SHAPE技术(使用方波)的改进，应该会使SHAPE在无创性确定门脉高压方面更敏感。
Subharmonic imaging (SHI) is a technique that uses the nonlinear oscillations of microbubbles when exposed to ultrasound at high pressures transmitting at the fundamental frequency i.e., fo and receiving at half the transmit frequency i.e., fo/2. Subharmonic aided pressure estimation (SHAPE) is based on the inverse relationship between the subharmonic amplitude of the microbubbles and the ambient pressure change. Eight waveforms with different envelopes were optimized with respect to acoustic power at which the SHAPE study is most sensitive. The study was run with four input transmit cycles, first in vitro and then in vivo in three canines to select the waveform that achieved the best sensitivity for detecting changes in portal pressures using SHAPE. A Logiq 9 scanner with a 4C curvi-linear array was used to acquire 2.5 MHz radio-frequency data. Scanning was performed in dual imaging mode with B-mode imaging at 4 MHz and a SHI contrast mode transmitting at 2.5 MHz and receiving at 1.25 MHz. Sonazoid, which is a lipid stabilized gas filled bubble of perfluorobutane, was used as the contrast agent in this study. A linear decrease in subharmonic amplitude with increased pressure was observed for all waveforms (r from −0.77 to −0.93; p<0.001) in vitro. There was a significantly higher correlation of the SHAPE gradient with changing pressures for the broadband pulses as compared to the narrowband pulses in both in vitro and in vivo results. The highest correlation was achieved with a Gaussian windowed binomial filtered square wave with an r-value of −0.95. One of the 3 canines was eliminated for technical reasons, while the other 2 produced very similar results to those obtained in vitro (r from −0.72 to −0.98; p<0.01). The most consistent in vivo results were achieved with the Gaussian windowed binomial filtered square wave (r = −0.95 and −0.96). In conclusion, using this waveform is an improvement to the existing SHAPE technique (where a square wave was used) and should make SHAPE more sensitive for noninvasively determining portal hypertension.
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DOI：
10.1016/j.jcmg.2011.08.017
发表时间：
2012-01
期刊：
JACC. Cardiovascular imaging
影响因子：
--
作者：
Dave JK;Halldorsdottir VG;Eisenbrey JR;Raichlen JS;Liu JB;McDonald ME;Dickie K;Wang S;Leung C;Forsberg F
通讯作者：
Forsberg F
影响因子：
2.3
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2.9
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DOI：
10.1109/tuffc.2005.1397351
发表时间：
2005-01-01
影响因子：
3.6
作者：
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影响因子：
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作者：
Forsberg, F;Shi, WT;Goldberg, BB
通讯作者：
Goldberg, BB