Research On High-speed Ultrasound Endoscopic Imaging System Based On 50kHz Pulse Repetition Frequency

Over the years,the prevalence and mortality of cardiovascular diseases in my country have been on the rise.Studies have shown that 70% of acute cardiovascular events are caused by thrombi formed by the rupture of vulnerable plaques in the coronary arteries.Therefore,accurate identification and early warning of plaque vulnerability are of great significance for reducing mortality.Intravascular imaging provides important help to improve the accuracy of plaque diagnosis.Among them,intravascular ultrasound imaging(intravascular ultrasound,IVUS)is currently the most commonly used intravascular imaging method in clinical practice.It has a large imaging depth and can provide overall structure information of plaques and blood vessels,but the resolution is low,and difficult to capture some details.Intravascular optical coherence tomography(IV-OCT)has a high-resolution capability,but the imaging depth is low.Using these two techniques alone is difficult to comprehensively detect and assess vulnerable plaques.The emerging optical coherence tomography-intravascular ultrasound(OCT-IVUS)has both the high resolution of optical imaging and the large depth of ultrasound imaging,which greatly improves the vulnerability to damage.The correct rate of plaque detection and diagnosis.However,due to the limitation of the pulse repetition frequency of IVUS,it is difficult for OCTIVUS to obtain a high number of imaging lines while imaging at a high frame rate,which in turn affects the display resolution.In order to increase the imaging speed of OCT-IVUS without reducing the display resolution of the image,this subject proposes a high frame rate ultrasound endoscopic imaging method based on high pulse repetition frequency: a 50 k Hz high pulse repetition frequency excitation is designed on this basis,a high-speed ultrasound endoscopic imaging system has been developed to help advance the high-speed,high-resolution OCT-IVUS to the clinic.The research content of this topic includes:(1)Hardware design: including the design and selection of excitation/receiving circuit,STM32,motion control module,imaging catheter,data acquisition card,etc.The hardware system of the lower computer that can be used for high-speed ultrasound endoscopic imaging is realized.(2)Software design: Using the producer/consumer structure,a set of Lab VIEW host computer software systems for high-speed ultrasound endoscopic imaging is designed.(3)Performance evaluation and imaging speed verification: The high-voltage pulse test and echo signal test of the excitation circuit show that the circuit can be used for excitation of25 MHz ultrasonic transducers and has a high signal-to-noise ratio.The imaging speed comparison experiment shows that the system developed based on this can significantly increase the imaging speed without reducing the display resolution.This technology is of great value for improving the imaging speed of OCT-IVUS and promoting its clinical application development.