Micro-vessel Imaging Based On Ultrasound Micro-bubbles And Its Application In Tumor Detection

Malignant tumors has become a major disease that seriously threatens human health and social development.Recently years,the morbidity of malignant tumors has been increasing globally,and it has become the leading cause of death in China.Studies have shown that during the early growth and development of tumors,accompanied by changes in tumor tissue angiogenesis and tumor cell structure,and the development of a new blood vessel network outside of existing blood vessels produces the tumor angiogenesis.This process is one of the early changes to distinguish normal tissue from cancerous tissue So,it is the phenomenon that makes it possible in early non-invasive diagnostic imaging of tumors.In recent years,many ultrasound teams at home and abroad have proposed ultrasound super-resolution imaging technology,which breaks the diffraction limit of ultrasound in principle and achieves micron-level resolution,providing a new imaging method for non-invasive micro-vascular detection.At present,the method is also being continuously optimized and explored in the application field,so as to realize the clinical application as soon as possible.In this study,we apply ultrasound super-resolution imaging technology to image and evaluate tumor micro-vessel changes.First,we set up a micro-vessel phantom experiment platform to conduct different types of micro-vessel simulation experiments.The micro-bubble concentration,experimental parameters and platform design are explored to verify the correctness of the designed ultrasonic super-resolution algorithm.Then,2-D and 3-D ultrasound super-resolution imaging experiments are performed on tumor mice to evaluate the potential of ultrasound super-resolution imaging in detecting tumor micro-vascular changes.At the same time,we also performed ultrasound Super-resolution imaging experiments on live chicken embryos and rat kidneys.The results of the study showed that :(1)In the 300μm spiral silicone rubber pipe and100 μm straight-pipe polyetheretherketone phantom experiments,a single micro-vessel cross-sectional profile with Full-Width at Half-Maxima of 143μm and 46μm could be imaged(the center frequency of transmit pulse is 8MHz,theoretical spatial resolution~200 μm).successfully verify the correctness of the designed ultrasonic super-resolution algorithm;(2)In the super-resolution experiment of healthy rat kidney,under the condition of maintaining free breathing,we successfully draw a single super-resolution micro-vascular image with half peak and full width of 18μm at the imaging depth of 1.3 cm,giving an upper limit to its resolution(wavelength λ/6),The distance between the two micro-vessels was FWHM=73 μm,(the center frequency of transmit pulse is 15 MHz,theoretical spatial resolution~103 μm);(3)In the tumor mice super-resolution experiment,we created a super-resolution image of the tumor micro-vessels while maintaining free breathing,and extracted the tumor vessel diameter parameters,and successfully introduced a 3-D super-resolution imaging experiment.By a series of body model of human blood vessel and in vivo kidney and tumor mice experiments,it has been proved that ultrasound super-resolution technology can be used to draw high-resolution micro-vascular images.Through 3-D ultrasound super-resolution imaging technology,It is expected to realize the feasibility of imaging detection of micro-vascular changes during tumor growth and development in different periods,and provide a research basis for clinical diagnosis of ultrasound super-resolution imaging technology.