High-resolution Ultrasound Superharmonic Imaging On Myocardial Microvascular

Cardiovascular coronary circulation consists of aortic circulation and myocardial microcirculation.Some research indicates that coronary artery disease is not only caused by aortic obstruction,but also related to myocardial microcirculation blood supply disorder.The angiography of myocardial microcirculation structure is crucially significant for the experimental research,as well as clinical diagnosis and treatment of many cardiovascular diseases.At present,there is no reliable non-invasive imaging technology to visualize the structure of living myocardial microcirculation,which is also a clinical technical problem that needs to be solved urgently.Reliable,non-invasive imaging of the living myocardium microcirculation structure can help the diagnosis of coronary artery disease quickly and accurately,greatly reducing the patient's pain and medical risks.Ultrasound imaging has irreplaceable technical advantages and application values because it is safe,non-invasive and real-time.It has always been a research hotspot in the field of cardiovascular imaging.In this paper,the high-resolution ultrasound superharmonic imaging technology on myocardial microvascular is researched in depth,and it provides a technical reference for its application to the imaging of living myocardial microcirculation.Taking the feature of myocardial microcirculation into consideration,this paper researched the method of ultrasound superharmonic myocardial microvascular imaging.In this method,microbubble contrast agent is a tracer of blood vessels,which will fill the whole myocardial microvessels with blood circulation.When low frequency array elements emit low frequency ultrasound,it will cause the corresponding size of microbubbles to resonate.Due to nonlinear effects,the reflected ultrasound will contain high-order or super-high harmonic components carrying vascular appearance information.These harmonic components are received by high-frequency array elements for imaging.This method enhances the contrast and sharpness of myocardial microvascular imaging,helping the diagnosis and treatment of cardiovascular diseases.The software and hardware technologies required for ultrasound superharmonic myocardial microvascular imaging were researched.In terms of hardware,the ultrasonic transmitting and receiving circuit suitable for ultrasound superharmonic myocardial microvascular imaging was designed and implemented,and it completed the high-efficiency emission of 5MHz ultrasound,as well as the low-noise amplification and acquisition of echo signals containing 30 MHz weak harmonic components.At the same time,the common mode noise sources appearing in the system was analyzed theoretically,and the solution was given.The effective suppression of common mode noise was successfully realized.In terms of software,this paper researched on some signal processing algorithms involved in ultrasonic superharmonic imaging systems,such as digital filter design and envelope detection,which successfully achieved the effective extraction of superharmonic signals.The ultrasound superharmonic myocardial microvascular imaging platform was designed,and semi-phantom experiment was carried out.The three-dimensional imaging of the 110?m inner diameter microvascular phantom was performed with an axial resolution of 300?m and a lateral resolution of 100?m.The result indicates that the method of ultrasound superharmonic imaging on myocardial microvascular is of high-resolution imaging capabilities.