Research On The Spectral Characteristics Of Ultrasound Transmission During Muscle Atrophy

For medical ultrasound diagnosis and treatment,the research on the transmission characteristics of biological tissues and the measurement of ultrasonic parameters is the most basic and important research topic.The ultrasonic characteristic parameters of muscle tissue can be obtained by various ultrasonic detection techniques,which can be used to evaluate the healthy state of human tissue and the application of characterizing pathological features.Ultrasound and muscle tissue interaction,ultrasonic absorption,sound attenuation and other phenomena,when the tissue pathological changes or functional changes,tissue elasticity,attenuation coefficient and other characteristics will be changed accordingly.It is easy to observe the structural pathological changes of the tissue and non-structural changes in the envelope information imaging of the ultrasonic signals by the traditional B-ultrasound and so on.Detection is difficult.The phase,correlation spectrum,power spectrum and other characteristic information of muscle tissue can be extracted from the received acoustic signal with tissue composition information,and the microstructure and function characteristics of muscle can be retrieved,thus the tissue state can be characterized by extracting the characteristic information of muscle tissue phase,correlation spectrum,power spectrum and so on.In this thesis,based on the theory of ultrasonic transmission,a theoretical model of ultrasonic transmission of muscle tissue is given to study the characteristics of ultrasonic transmission spectrum of muscle in the process of muscular atrophy under tail suspension model in rats.Combined with ultrasound,wet weight and biochemical indexes,ultrasonic spectrum analysis was used to detect the process of muscle atrophy in rats.At the end of this paper,we also try to study the characteristics of ultrasonic transmission frequency under the influence of different intensity of low-frequency pulse ultrasound on muscle tissue.Theoretical and experimental studies show that:(1)When the diameter of muscle fiber in skeletal muscle simulation model becomes smaller,the high frequency component of sound wave power spectrum transmitted in vertical direction will increase;With the other parameters unchanged,the muscle fiber hardness of skeletal muscle decreases,and the high frequency component of the power spectrum of the acoustic signal transmitted in the direction of the vertical fiber increases.(2)In the tail suspension model group,there were more high frequency components in the power spectrum after ultrasonic transmission in the process of muscle atrophy,which showed that the peak frequency point deviated to the high frequency end.(3)Taking the spectral center frequency of the control group as an index,the spectral offset of the tail hanging group is not proportional to the experimental days.(4)By comparing the transmission spectrum characteristics of the control group,the tail hanging group and the parameter group(low frequency ultrasound irradiation),it is shown that the absorption frequency of sound waves is different in different states of muscle tissue.The change of center frequency of ultrasonic spectrum can be used as a method to characterize the degree of muscle atrophy.In this thesis,the results of ultrasonic spectrum changes after muscular atrophy can provide a new method for non-invasive detection of muscular atrophy.