The Primary Study On The Reliability Of The Shear Wave Elastography Technology To Detecting Elasticity Modulus Of Carotid Plaque

Objective:Shear Wave Elastography (SWE) Technology is commonly used to detect the elasticity modulus value of human soft tissue. The aim of this study was to quantitatively analyze and assess the reliability of the SWE Technology to detecting elasticity modulus of human carotid atherosclerosis (CAS) plaques.Methods:1. To assess the repeatability for SWE technology for detecting the elastic parameters of carotid plaques;2. To analyze the correlation of propagation velocity of shear wave detected by SWE technology in vivo and in vitro from CAS plaques;3. To analyze the elasticity modulus detected by SWE and the actual values from nanoindentation technology in vitro.We can comprehensively assess the reliability of the SWE technology on detection CAS plaques when we make the detection results from SWE technology in vivo and nanoindentation technology in vitro contact perfectly through the three aspects above.The specific details of method are as follows:(1) Assessment of the repeatability of the SWE technology for detecting the elasticity parameters of carotid plaques.Randomly selected three cases of carotid atherosclerosis patients with CAS plaques diagnosed by ultrasound, repeatedly detected multipoint elasticity parameters of plaques in vivo using the SWE technology. Acquired 135 mean velocity values of shear wave propagation from 9 ROIs of 3 plaques. Analyzed and assessed the repeatability of the SWE technology in vivo for detection CAS plaque elastic parameters.(2) Control study on the variance and correlation of velocity values of shear wave propagation detected by the SWE technology in vivo and in vitro from CAS plaques.Randomly selected three carotid atherosclerosis patients diagnosed by ultrasound and were to receive carotid endarterectomy the following day for multipoint repeated detections of the mean values of the shear wave velocity from carotid plaques either in vivo in human subjects or in vitro in 0.9% saline after excision using the SWE technology. There were 270 mean velocity values of shear wave acquired from 18 ROIs of 3 plaques. The variance and correlation of elasticity properties of carotid plaques in two kinds of environment were quantitatively analyzed, in vivo and in vitro.(3) Control study on the variance and correlation of elasticity moduli of CAS plaques respectively detected by the SWE technology and nano indentation technology in vitro.Three complete CAS plaque specimens from endarterectomy were selected and repeatedly multipoint detected for the mean values of the elasticity modulus in vitro in 0.9% saline respectively using the SWE technology and nanoindentation technology. There were 135 mean values of the elasticity modulus of CAS plaques acquired from 9 ROIs of 3 plaques using SWE technology and 27 elasticity modulus values acquired from the same ROIs using nanoindentation technology. Control analyzed the variance and the correlation between the results of two detection methods. Above all, the reliability of SWE technology for detecting the elastic parameters of CAS plaque could be comprehensively evaluated.Results:(1) Inter-frame coefficient of variation values of the SWE technology ranged from 0.04-0.43 in vivo. Intra-class correlation coefficient values (r) of the SWE technology ranged from 0.68-0.89 in vivo, p ranged from 0.002 to 0.005. SWE technology provided reproducible measurements. There were significant variation and correlation between the values of shear wave velocity for three acquisitions for each position for each patient.(2) Inter-frame coefficient of variation values of SWE technology ranged from 0.043-0.432 in vivo and from 0.005-0.093 in vitro. Intra-class correlation coefficient values (r) of SWE technology ranged from 0.678-0.815 in vivo and from 0.755-0.999 in vitro. p<0.01. The mean velocity values of shear waves acquired in vitro were significantly higher than those in vitro using SWE technology (p=0.005). There was a positive linear correlation between the mean velocity values in vivo and in vitro from SWE technology (p=0.002). r=0.880, R2=0.775.(3) Intra-class correlation coefficient RA= 1.000, p≥0.999,p=0.000 from SWE technology in vitro and RB=0.986, p≥0.946,p=0.000 from nanoindentation technology in vitro. The mean values of the elasticity modulus of CAS plaques acquired by na no indentation technology were significantly higher than those acquired using SWE technology in vitro (p=0.000). There was a positive quadratic curve correlation between the results of elasticity modulus from the two technology in vitro (p= 0.002), R2=0.993.Conclusions:(1) SWE technology provided reproducible measurements.(2) There was significant variation between the values of shear wave velocity from SWE technology in vivo and in vitro. SWE technology can be used for detecting the elasticity parameters of the human carotid plaques both in vivo and in vitro, and the detection in vitro provided higher stability and reproducibility. The complex environment in the human body has a certain influence on the results for SWE technology to detect elastic parameters of carotid plaques.(3) Both of SWE and nanoindentation technology have good stability and reproducibility on the detection in vitro. SWE technology provided higher stability and reproducibility than nanoindentation technology. The elasticity moduli from SWE technology were not the real values. The calculation equations of elastic modulus in SWE technology does not apply to the CAS plaque. There may be a calculation equation for elastic modulus more suitable for CAS plaque in SWE technology. SWE technology can be applied to real value detection of the elasticity modulus of CAS plaque, with the corrected calculation equation.