Intravascular ultrasound (IVUS) is widely used in coronary artery examination. Ultrasonic elastography combined with IVUS is very conspicuous in identifying plaque component and in detecting plaque vulnerability degree. In this study, a simulation model of the blood vessel based on finite element analysis (FEA) was established. The vessel walls generally have radial changes caused by different intravascular pressure. The signals at lower pressures were used as the pre-deformation data and the signals at higher pressure were used as the post-deformation data. Displacement distribution was constructed using the time-domain cross-correlation method, and then strain images. By comparison of elastograms under different pressures, we obtained the optimal pressure step. Furthermore, on the basis of the obtained optimize pressure step, the simulation results showed that this method could effectively distinguish characteristics between different component plaques, and could guide the later experiments and clinical applications.
Angiography ; Arteries ; diagnostic imaging ; pathology ; Elasticity Imaging Techniques ; Finite Element Analysis ; Humans ; Plaque, Atherosclerotic ; diagnostic imaging ; Pressure

Objective To study the effect and mechanism of Qili Qiangxin Capsule (QQC)on myocar dial fibrosis of rats with myocardial infarction(MI).Methods Acute myocardial infarction (AMI)mod-el was induced by ligation of the proximal left anterior descending branch of coronary artery of SD male rats for four weeks.Then the survival rats with AMI were randomly divided into model group (n =12)or QQC group (n =9)according to the transthoracic echocardiography results,and 10 more rats were as-signed into sham operation group.Rats of QQF group were intragastrically administered QQC at the dose of 1 g/kg once daily,while those of the other two groups took the same volume of distilled water,for con-secutive four weeks.The cardiac function was measured using echocardiography,the myocardial tissue close to infarction was observed with HE or Masson staining,α-SMA expression in myocardial tissue was detected using immunohistochemistrical method,and protein expression of α-SMA,collagen I,transfor-ming growth factor-β1 (TGF-β1 )and p-Smad3 were detected using Western blotting.Results Compared with the sham operation group,left ventricular fractional shortening (FS)and ejection fraction (EF)of model group were significantly lower (P <0.05),left ventricular end systolic diameter (LVID)and end systolic volume (ESV)increased significantly (P <0.05 ),myocardial fibrosis ratio was significantly higher (P <0.05),and the protein expression of α-SMA,collagenⅠ,TGF-β1 and p-Smad3 were higher (P <0.05 ).Compared with model group,EF and FS of QQF group were significantly lower (P <0.05),LVID and ESV were significantly higher(P <0.05),the degree of myocardial fibrosis was re-lieved,and α-SMA,collagenⅠ,TGF-β1 ,p-Smad3 protein expressions in myocardium were lower(P <0.05).Conclusion Qili Qiangxin Capsule was demonstrated to improve the cardiac function of rats with AMI by inhibiting the process of fibrosis remodeling,and the effects may be mediated through regu-lating TGF-β1 /Smad3 signaling pathway.

An intravascular ultrasound-enhanced thrombolysis excitation system with adjustable frequency, amplitude and duty cycle was designed based on FPGA (ZYNQ-7Z020). Firstly, the FPGA generated waveform amplitude binary data based on direct digital frequency synthesis (DDS) technology, and then the data was converted into burst signal through an external daughter card, which included D/A conversion circuit, active low-pass filter, power amplifier circuit and impedance matching circuit. The test results demonstrated that the output waveform reached the target with advantages of simple implementation and flexible control, the peak negative pressure generated from ultrasound transducer was doubled by means of an electrical impedance matching network. In vitro thrombus models were applied to verify the excitation system, it turned out that ultrasound cavitation effect generated could accelerate the penetration of urokinase and increase the thrombolysis rate by about 20%.
Amplifiers, Electronic ; Electric Impedance ; Thrombolytic Therapy ; Ultrasonography ; Ultrasonography, Interventional

The ultrasound endoscopic probes with very small size transducers are normally imaging by focused ultrasound beamforming technology. So the imaging frame rate is not very high, which cannot meet the needs of some clinical applications based on high imaging rate. In recent years, plane-wave ultrafast imaging technology can obtain high image frame rate and guarantee the image quality. In this paper, a plane wave ultra-fast imaging technique based on a home-made small line array ultrasound transducer is presented. Feasibility of the method is verified by simulation estimations and phantom experiments. The results show that for the small size transducer design of plane wave ultrafast imaging, it is necessary to fully consider the combination of the array element width and the number of array elements. So that a good plane wave imaging quality can be obtained. It lays a foundation for the ultra-fast imaging of plane wave in the interventional ultrasound imaging and ultrasound endoscopy.
Phantoms, Imaging ; Transducers ; Ultrasonography ; instrumentation

Multi-angle plane-wave beamforming algorithm is the basis of ultra-fast ultrasonic imaging. It can be used to improve the imaging frame rate and resolution of traditional focused ultrasound. However, the existing multi-angle plane-wave technology can not satisfy the real-time imaging requirements due to the huge amount of computation required by CPU. In this paper, We proposed a parallel processing method to reduce the computation time based on compute unified device architecture(CUDA). Simulation analysis and contrast experiment were conducted to verify its performance. Experimental results show that the execution time based on GPU is much less than that based on CPU, thus the computational speed is accelerated significantly to satisfy the demand of ultrafast imaging.