BACKGROUND Endoscopic ultrasound(EUS)and endoscopic ultrasound elastography(EUS-E)simulation lessens the learning curve;however,models lack realism,diminishing competitiveness.AIM To standardize the mechanical propert...BACKGROUND Endoscopic ultrasound(EUS)and endoscopic ultrasound elastography(EUS-E)simulation lessens the learning curve;however,models lack realism,diminishing competitiveness.AIM To standardize the mechanical properties of polyvinyl alcohol(PVA)hydrogel for simulating organs and digestive lesions.METHODS PVA hydrogel(Sigma Aldrich,degree of hydrolysis 99%)for simulating EUS/EUS-E lesions was investigated in Unidad de Investigación y Desarrollo Tecnológico at Hospital General de México“Dr.Eduardo Liceaga”,Mexico City.We evaluated physical,contrast,elasticity and deformation coefficient characteristics in lesions,applying Kappa’s concordance and satisfaction questionnaire(Likert 4-points).RESULTS PVA hydrogel showed stable mechanical properties.Density depended on molecular weight(MW)and concentration(C).PVA bblocks with the greatest density showed lowest tensile strength(r=-0.8,P=0.01).Lesions were EUSgraphically visible.Homogeneous and heterogeneous examples were created from PVA blocks or PVA phantoms,exceeding(MW2=146000-186000,C9=15%and C10=20%)with a density under(MW1=85000-124000,C1=7%and C2=9%).We calculated elasticity and deformation parameters of solid(blue)areas,contrasting with the norm(Kappa=0.8;high degree of satisfaction).CONCLUSION PVA hydrogels were appropriate for simulating organs and digestive lesions using EUS/EUS-E,facilitating practice and reducing risk.Repetition amplified skills,while reducing the learning curve.展开更多
Ultrasound simulation for carotid arteries is helpful to the performance assessments of vessel wall detection and signal processing methods by using ultrasound techniques. An ul- trasound simulation method of carotid ...Ultrasound simulation for carotid arteries is helpful to the performance assessments of vessel wall detection and signal processing methods by using ultrasound techniques. An ul- trasound simulation method of carotid artery wall with a three-membrane structure is proposed in present study. According to the ultrasound speckle distributions varying with the shapes and densities of scatterer distributions, as well as the statistic results of the clinical images, the parameters of distributions, densities and intensities of scatterers for different kinds of tissues in the carotid artery phantoms are determined. Each region is acoustically characterized using FIELD II software to produce the radio frequency echo signals, from which ultrasound images are derived. The results based on 30 simulations show that the echo distributions of the intimae, mediae, adventitias and blood are consistent with the clinical ones. Moreover, compared with the results from the central frequency of 8 MHz, the mean measurements for thicknesses of the intima, media and adventitia membranes, as well as the lumen diameter from the simulation images based on 12 MHz are the same as the preset ones, and the maximum relative errors are the 4.01%, 1.25%, 0.04% and 0.15%, respectively. The simulation under this condition is more realistic.展开更多
The purpose of this study is to establish the simulation model of the gas emboli by analyzing reasons for features of gas emboli Doppler ultrasound signals. It is useful for the further classification of the solid emb...The purpose of this study is to establish the simulation model of the gas emboli by analyzing reasons for features of gas emboli Doppler ultrasound signals. It is useful for the further classification of the solid emboli and gas emboli. First, the model of the radiation force and the drag force is used to calculate forces acting on the gas emboli. Second, the acceleration of the gas emboli is calculated in both the radial direction and the axial direction of the vessel, which is used to calculate the trajectory of the gas emboli in the vessel. Finally, the computer simulation model is established for the gas emboli. Doppler ultrasound signals of the gas emboli and the solid emboli are generated in the simulation experiment. Experimental results show that compared with the solid emboli, the gas emboli acted by the radiation force and the drag force will result in the frequency-domain broaden in the Doppler spectrogram. When the gas emboli circulate from the low speed area to the high speed one and then from the high speed area back to the low speed one, a ＂V＂ shape will be shown in the spectrogram of gas emboli signals. When the gas emboli circulate from the low speed area to the high speed one or from the high speed area to the low speed one, a diagonal shape will be shown for gas emboli signals. It is also shown that features of simulated gas emboli signals match with those of gas emboli signals sampled from clinic. All demonstrate that the simulation method of the gas emboli is reasonable.展开更多
文摘BACKGROUND Endoscopic ultrasound(EUS)and endoscopic ultrasound elastography(EUS-E)simulation lessens the learning curve;however,models lack realism,diminishing competitiveness.AIM To standardize the mechanical properties of polyvinyl alcohol(PVA)hydrogel for simulating organs and digestive lesions.METHODS PVA hydrogel(Sigma Aldrich,degree of hydrolysis 99%)for simulating EUS/EUS-E lesions was investigated in Unidad de Investigación y Desarrollo Tecnológico at Hospital General de México“Dr.Eduardo Liceaga”,Mexico City.We evaluated physical,contrast,elasticity and deformation coefficient characteristics in lesions,applying Kappa’s concordance and satisfaction questionnaire(Likert 4-points).RESULTS PVA hydrogel showed stable mechanical properties.Density depended on molecular weight(MW)and concentration(C).PVA bblocks with the greatest density showed lowest tensile strength(r=-0.8,P=0.01).Lesions were EUSgraphically visible.Homogeneous and heterogeneous examples were created from PVA blocks or PVA phantoms,exceeding(MW2=146000-186000,C9=15%and C10=20%)with a density under(MW1=85000-124000,C1=7%and C2=9%).We calculated elasticity and deformation parameters of solid(blue)areas,contrasting with the norm(Kappa=0.8;high degree of satisfaction).CONCLUSION PVA hydrogels were appropriate for simulating organs and digestive lesions using EUS/EUS-E,facilitating practice and reducing risk.Repetition amplified skills,while reducing the learning curve.
基金supported by the National Natural Science Foundation of China(Grant 61261007)the Key Program of Yunnan Natural Science Foundation(Grant 2013FA008)
文摘Ultrasound simulation for carotid arteries is helpful to the performance assessments of vessel wall detection and signal processing methods by using ultrasound techniques. An ul- trasound simulation method of carotid artery wall with a three-membrane structure is proposed in present study. According to the ultrasound speckle distributions varying with the shapes and densities of scatterer distributions, as well as the statistic results of the clinical images, the parameters of distributions, densities and intensities of scatterers for different kinds of tissues in the carotid artery phantoms are determined. Each region is acoustically characterized using FIELD II software to produce the radio frequency echo signals, from which ultrasound images are derived. The results based on 30 simulations show that the echo distributions of the intimae, mediae, adventitias and blood are consistent with the clinical ones. Moreover, compared with the results from the central frequency of 8 MHz, the mean measurements for thicknesses of the intima, media and adventitia membranes, as well as the lumen diameter from the simulation images based on 12 MHz are the same as the preset ones, and the maximum relative errors are the 4.01%, 1.25%, 0.04% and 0.15%, respectively. The simulation under this condition is more realistic.
基金supported by the Natural Science Foundation of China(10974035)the Program of Shanghai Subject Chief Scientist(10XD1400600)
文摘The purpose of this study is to establish the simulation model of the gas emboli by analyzing reasons for features of gas emboli Doppler ultrasound signals. It is useful for the further classification of the solid emboli and gas emboli. First, the model of the radiation force and the drag force is used to calculate forces acting on the gas emboli. Second, the acceleration of the gas emboli is calculated in both the radial direction and the axial direction of the vessel, which is used to calculate the trajectory of the gas emboli in the vessel. Finally, the computer simulation model is established for the gas emboli. Doppler ultrasound signals of the gas emboli and the solid emboli are generated in the simulation experiment. Experimental results show that compared with the solid emboli, the gas emboli acted by the radiation force and the drag force will result in the frequency-domain broaden in the Doppler spectrogram. When the gas emboli circulate from the low speed area to the high speed one and then from the high speed area back to the low speed one, a ＂V＂ shape will be shown in the spectrogram of gas emboli signals. When the gas emboli circulate from the low speed area to the high speed one or from the high speed area to the low speed one, a diagonal shape will be shown for gas emboli signals. It is also shown that features of simulated gas emboli signals match with those of gas emboli signals sampled from clinic. All demonstrate that the simulation method of the gas emboli is reasonable.
