Study On The Application Of Photoacoustic Imaging Technology In Human Peripheral Vessels

Vascular diseases,including cerebrovascular disease and peripheral vascular disease,have a high mortality rate and are prone to serious sequelae.Clinical imaging techniques such as magnetic resonance imaging,ultrasound doppler imaging,X-ray and CT have limitations in the detection and monitoring of blood vessels.Photoacoustic tomography(PAT)is a hybrid imaging method which combines the characteristics of optical imaging and ultrasonic imaging.It has both the high contrast and multispectral imaging capability of optical imaging,and the high resolution comparable to ultrasonic imaging.In addition,PAI is less costly and can carry out non-invasive examination of biological tissue.In recent years,it has played an important role in basic biological research and clinical application research.The main work of this article includes:1.Introduced the photoacoustic imaging principle and the photoacoustic tomography system.We introduced the photoacoustic effect,the photoacoustic wave equation,the image reconstruction algorithm and the principle of system construction.These provided the theoretical basis for our paper.We explained each module in the photoacoustic tomography system in detail,including laser,optical parametric oscillator,data acquisition system,amplifier,probe and software for data acquisition and image reconstruction.2.Animal experiment to explore the imaging and monitoring ability of photoacoustic tomography on small vessels.We obtained high-resolution reconstructed images of small vessels in the mouse brain and monitored hemodynamics changes in the region of interest.The animals were divided into three groups,each with a sample size of 8.We performed dynamic imaging and statistical analysis on three groups of samples under electrical stimulation at Hegu,Zhongwan and sham acupoints respectively.Through the animal experiment,we have proved the ability of the system to monitor the blood flow of small vessels,and established the analysis method,which laid the foundation for the follow-up monitoring of human peripheral blood vessels.3.Explore the imaging and monitoring ability of photoacoustic tomography on human peripheral blood vessels.First,we obtained a high-resolution coronal image of the human finger,then we used ultrasound imaging for cross-validation.We obtained the distribution maps of oxyhemoglobin and deoxyhemoglobin using multi-wavelength imaging method,which pointed the position of the region of interest in the human finger.We introduced vessel stimulation test and used a pressure cuff to induce the occlusion of finger vessels,then the dynamic changes of peripheral blood hemodynamics in the fingers were monitored.We demonstrated the imaging and monitoring potential of photoacoustic imaging in human peripheral blood vessels.Finally,we recruited 6 healthy volunteers and 3 diabetic patients to image the finger blood vessels of the two groups of volunteers and monitor their hemodynamic changes before and after vascular occlusion.Comparing the results of dynamic imaging and statistical analysis in the course of vascular occlusion and recovery between diabetic patients and healthy volunteers,we found that the vascular function of diabetic patients decreased.These results demonstrated the potential of photoacoustic tomography in the assessment of peripheral vascular function and monitoring of peripheral vascular symptoms in clinical.