This study explores the significance of using two-dimensional shear wave elastography(2D-SWE)to assess liver stiffness(LS)and spleen area(SPA)for predicting post-hepatectomy liver failure(PHLF).By providing a non-inva...This study explores the significance of using two-dimensional shear wave elastography(2D-SWE)to assess liver stiffness(LS)and spleen area(SPA)for predicting post-hepatectomy liver failure(PHLF).By providing a non-invasive method to measure LS,which correlates with the degree of liver fibrosis,and SPA,an indicator of portal hypertension,2D-SWE offers a comprehensive evaluation of a patient’s hepatic status.These advancements are particularly crucial in hepatic surgery,where accurate preoperative assessments are essential for optimizing surgical outcomes and minimizing complications.This letter highlights the prac-tical implications of integrating 2D-SWE into clinical practice,emphasizing its potential to improve patient safety and surgical precision by enhancing the ability to predict PHLF and tailor surgical approaches accordingly.展开更多
BACKGROUND Thyroid dysfunction during pregnancy is an important disease affecting the health of mothers and children.Two-dimensional(2D)shear wave elastography(SWE)is the newest ultrasonic elastography technology and ...BACKGROUND Thyroid dysfunction during pregnancy is an important disease affecting the health of mothers and children.Two-dimensional(2D)shear wave elastography(SWE)is the newest ultrasonic elastography technology and its value in differentiating benign and malignant thyroid nodules has been widely recognized.However,the value of 2D SWE in evaluating and predicting thyroid function is unclear.AIM To explore prospectively the value of 2D SWE quantitative analysis for the evaluation of thyroid function in the first trimester.METHODS We included outpatients of reproductive age in the Department of Gynecology in Shanghai Changning Maternity and Infant Health Hospital between March 2023 and March 2024 who had conventional ultrasound examination and 2D SWE of the thyroid.They also underwent transvaginal ultrasound examination to confirm early intrauterine pregnancy and serum thyroid stimulating hormone(TSH)level was measured.The patients were divided into pregnant with normal TSH,pregnant with abnormal TSH,and nonpregnant with normal TSH.Conventional ultrasound and 2D SWE results were compared among the three groups.RESULTS A total of 108 patients were included in the study;57 in the pregnant with normal TSH group,18 in the pregnant with abnormal TSH group and 33 were in the nonpregnant with normal TSH group.Thyroid size,thyroid echotexture,2D SWE quantitative parameters including mean elasticity in the region of interest and maximal elasticity in the region of interest showed no significant differences among the three groups(P>0.05).CONCLUSION Conventional ultrasound and 2D SWE features could not reflect the level of serum TSH.展开更多
BACKGROUND The clinical management and prognosis differ between benign and malignant solid focal liver lesions(FLLs),as well as among different pathological types of malignant FLLs.Accurate diagnosis of the possible t...BACKGROUND The clinical management and prognosis differ between benign and malignant solid focal liver lesions(FLLs),as well as among different pathological types of malignant FLLs.Accurate diagnosis of the possible types of solid FLLs is important.Our previous study confirmed the value of shear wave elastography(SWE)using maximal elasticity(Emax)as the parameter in the differential diagnosis between benign and malignant FLLs.However,the value of SWE in the differential diagnosis among different pathological types of malignant FLLs has not been proved.AIM To explore the value of two-dimensional SWE(2D-SWE)using Emax in the differential diagnosis of FLLs,especially among different pathological types of malignant FLLs.METHODS All the patients enrolled in this study were diagnosed as benign,malignant or undetermined FLLs by conventional ultrasound.Emax of FLLs and the periphery of FLLs was measured using 2D-SWE and compared between benign and malignant FLLs or among different pathological types of malignant FLLs.RESULTS The study included 32 benign FLLs in 31 patients and 100 malignant FLLs in 96 patients,including 16 cholangiocellular carcinomas(CCCs),72 hepatocellular carcinomas(HCCs)and 12 liver metastases.Thirty-five FLLs were diagnosed as undetermined by conventional ultrasound.There were significant differences between Emax of malignant(2.21±0.57 m/s)and benign(1.59±0.37 m/s)FLLs(P=0.000),and between Emax of the periphery of malignant(1.52±0.39 m/s)and benign(1.36±0.44 m/s)FLLs(P=0.040).Emax of liver metastases(2.73±0.99 m/s)was significantly higher than that of CCCs(2.14±0.34 m/s)and HCCs(2.14±0.46 m/s)(P=0.002).The sensitivity,specificity and accuracy were 71.00%,84.38%and 74.24%respectively,using Emax>1.905 m/s(AUC 0.843)to diagnose as malignant and 23 of 35(65.74%)FLLs with undetermined diagnosis by conventional ultrasound were diagnosed correctly.CONCLUSION Malignant FLLs were stiffer than benign ones and liver metastases were stiffer than primary liver carcinomas.2D-SWE with Emax was a useful complement to conventional ultrasound for the differential diagnosis of FLLs.展开更多
Two-dimensional shear wave elastography(2D-SWE)is used in the clinical setting for observation of the liver.Unfortunately,a wide spectrum of artifactual images are frequently encountered in 2D-SWE,the precise mechanis...Two-dimensional shear wave elastography(2D-SWE)is used in the clinical setting for observation of the liver.Unfortunately,a wide spectrum of artifactual images are frequently encountered in 2D-SWE,the precise mechanisms of which remain incompletely understood.This review was designed to present many of the artifactual images seen in 2D-SWE of the liver and to analyze them by computer simulation models that support clinical observations.Our computer simulations yielded the following suggestions:(1)When performing 2D-SWE in patients with chronic hepatic disease,especially liver cirrhosis,it is recommended to measure shear wave values through the least irregular hepatic surface;(2)The most useful 2D-SWE in patients with focal lesion will detect lesions that are poorly visible on B-mode ultrasound and will differentiate true tumors from pseudo-tumors(e.g.,irregular fatty change);and(3)Measurement of shear wave values in the area posterior to a focal lesion must be avoided.展开更多
BACKGROUND Post-hepatectomy liver failure(PHLF)increases morbidity and mortality after liver resection for patients with advanced liver fibrosis and cirrhosis.Preoperative liver stiffness using two-dimensional shear w...BACKGROUND Post-hepatectomy liver failure(PHLF)increases morbidity and mortality after liver resection for patients with advanced liver fibrosis and cirrhosis.Preoperative liver stiffness using two-dimensional shear wave elastography(2D-SWE)is widely used to evaluate the degree of fibrosis.However,the 2D-SWE results were not accurate.A durometer measures hardness by quantifying the ability of a material to locally resist the intrusion of hard objects into its surface.However,the durometer score can only be obtained during surgery.To measure correlations among 2D-SWE,palpation by surgeons,and durometermeasured objective liver hardness and to construct a liver hardness regression model.METHODS We enrolled 74 hepatectomy patients with liver hardness in a derivation cohort.Tactile-based liver hardness scores(0-100)were determined through palpation of the liver tissue by surgeons.Additionally,liver hardness was measured using a durometer.Correlation coefficients for durometer-measured hardness and preoperative parameters were calculated.Multiple linear regression models were constructed to select the best predictive durometer scale.Receiver operating characteristic(ROC)curves and univariate and multivariate analyses were used to calculate the best model’s prediction of PHLF and risk factors for PHLF,respectively.A separate validation cohort(n=162)was used to evaluate the model.RESULTS The stiffness measured using 2D-SWE and palpation scale had good linear correlation with durometer-measured hardness(Pearson rank correlation coefficient 0.704 and 0.729,respectively,P<0.001).The best model for the durometer scale(hardness scale model)was based on stiffness,hepatitis B virus surface antigen,and albumin level and had an R2 value of 0.580.The area under the ROC for the durometer and hardness scale for PHLF prediction were 0.807(P=0.002)and 0.785(P=0.005),respectively.The optimal cutoff value of the durometer and hardness scale was 27.38(sensitivity=0.900,specificity=0.660)and 27.87(sensitivity=0.700,specificity=0.787),respectively.Patients with a hardness scale score of>27.87 were at a significantly higher risk of PHLF with hazard ratios of 7.835(P=0.015).The model’s PHLF predictive ability was confirmed in the validation cohort.CONCLUSION Liver stiffness assessed by 2D-SWE and palpation correlated well with durometer hardness values.The multiple linear regression model predicted durometer hardness values and PHLF.展开更多
Objective:To explore the feasibility of two-dimensional shear wave elastography in evaluating calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome.Methods:A total of 48 di...Objective:To explore the feasibility of two-dimensional shear wave elastography in evaluating calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome.Methods:A total of 48 diabetic nephropathy patients with medial tibial stress syndrome from January 2020 to December 2022 were included as the study group,and 48 patients with diabetic nephropathy during the same period were included as the control group.Both groups were detected by two-dimensional shear wave elastography with ultrasonic equipment,and Young‘s modulus of the tibialis anterior muscle,tibialis posterior muscle,and gastrocnemius muscle were observed and analyzed in the two groups.Results:The Young‘s modulus values of tibialis anterior muscle,tibialis posterior muscle,and gastrocnemius muscle in the study group were significantly lower than those in the control group(P<0.05).Conclusion:Two-dimensional shear wave elastography is feasible for the evaluation of calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome,and has high accuracy and repeatability.This technique can be used to diagnose,treat and monitor muscle lesions in patients with diabetic nephropathy,and can also be used to assess muscle fatigue and exercise capacity,which has broad application prospects.展开更多
Two-dimensional shear wave elastography(2D-SWE) is a rapid, simple and novel noninvasive method that has been proposed for assessing hepatic fibrosis in patients with chronic liver diseases(CLDs) based on measurements...Two-dimensional shear wave elastography(2D-SWE) is a rapid, simple and novel noninvasive method that has been proposed for assessing hepatic fibrosis in patients with chronic liver diseases(CLDs) based on measurements of liver stiffness. 2 D-SWE can be performed easily at the bedside or in an outpatient clinic and yields immediate results with good reproducibility. Furthermore, 2 D-SWE was an efficient method for evaluating liver fibrosis in small to moderately sized clinical trials. However, the quality criteria for the staging of liver fibrosis are not yet well defined. Liver fibrosis is the main pathological basis of liver stiffness and a key step in the progression from CLD to cirrhosis; thus, the management of CLD largely depends on the extent and progression of liver fibrosis. 2 D-SWE appears to be an excellent tool for the early detection of cirrhosis and may have prognostic value in this context. Because 2 D-SWE has high patient acceptance, it could be useful for monitoring fibrosis progression and regression in individual cases. However, multicenter data are needed to support its use. This study reviews the current status and future perspectives of 2 D-SWE for assessments of liver fibrosis and discusses the technical advantages and limitations that impact its effective and rational clinical use.展开更多
Liver biopsy is the gold standard for evaluating the degree of liver fibrosis in patients with chronic liver disease. However, due to the many limitations of liver biopsy, there has been much interest in the use of no...Liver biopsy is the gold standard for evaluating the degree of liver fibrosis in patients with chronic liver disease. However, due to the many limitations of liver biopsy, there has been much interest in the use of noninvasive techniques for this purpose. Among these techniques real-time two-dimensional shear wave elastography(2D-SWE) has the advantage of measuring tissue elasticity with the guidance of B-mode images. Recently, many studies have been conducted on the application of 2D-SWE in patients with various liver diseases, and their validity has been confirmed. Here, we briefly discuss the role of 2D-SWE in patients with chronic liver diseases, particularly aspects of the examination techniques and clinical applications.展开更多
Background:Liver fibrosis is a common pathological change caused by a variety of etiologies.Early diagnosis and timely treatment can reverse or delay disease progression and improve the prognosis.This study aimed to a...Background:Liver fibrosis is a common pathological change caused by a variety of etiologies.Early diagnosis and timely treatment can reverse or delay disease progression and improve the prognosis.This study aimed to assess the potential utility of two-dimensional shear wave elastography and texture analysis in dynamic monitoring of the progression of liver fibrosis in rat model.Methods:Twenty rats were divided into control group(n=4)and experimental groups(n=4 per group)with carbon tetrachloride administration for 2,3,4,and 6 weeks.The liver stiffness measurement was performed by two-dimensional shear wave elastography,while the optimal texture analysis subsets to distinguish fibrosis stage were generated by MaZda.The results of elastography and texture analysis were validated through comparing with histopathology.Results:Liver stiffness measurement was 6.09±0.31 kPa in the control group and 7.10±0.41 kPa,7.80±0.93 kPa,8.64±0.93 kPa,9.91±1.13 kPa in the carbon tetrachloride induced groups for 2,3,4,6 weeks,respectively(P<0.05).By texture analysis,histogram and co-occurrence matrix had the most frequency texture parameters in staging liver fibrosis.Receiver operating characteristic curve of liver elasticity showed that the sensitivity and specificity were 95.0%and 92.5%to discriminate liver fibrosis and non-fibrosis,respectively.In texture analysis,five optimal parameters were selected to classify liver fibrosis and non-fibrosis.Conclusions:Two-dimensional shear wave elastography showed potential applications for noninvasive monitoring of the progression of hepatic fibrosis,even in mild fibrosis.Texture analysis can further extract and quantify the texture features in ultrasonic image,which was a supplementary to further visual information and acquired high diagnostic accuracy for severe fibrosis.展开更多
BACKGROUND Few systematic comparative studies of the different methods of physical elastography of the spleen are currently available.AIM To compare point shear wave and two-dimensional elastography of the spleen cons...BACKGROUND Few systematic comparative studies of the different methods of physical elastography of the spleen are currently available.AIM To compare point shear wave and two-dimensional elastography of the spleen considering the anatomical location(upper,hilar,and lower pole).METHODS As part of a prospective clinical study,healthy volunteers were examined for splenic elasticity using four different ultrasound devices between May 2015 and April 2017.The devices used for point shear wave elastography were from Siemens(S 3000)and Philips(Epiq 7),and those used for two-dimensional shear wave elastography were from GE(Logiq E9)and Toshiba(Aplio 500).In addition,two different software versions(5.0 and 6.0)were evaluated for the Toshiba ultrasound device(Aplio 500).The study consisted of three arms:A,B,and C.RESULTS In study arm A,200 subjects were evaluated(78 males and 122 females,mean age 27.9±8.1 years).In study arm B,113 subjects were evaluated(38 men and 75 women,mean age 26.0±6.3 years).In study arm C,44 subjects were enrolled.A significant correlation of the shear wave velocities at the upper third of the spleen(r=0.33088,P<0.0001)was demonstrated only for the Philips Epiq 7 device compared to the Siemens Acuson S 3000.In comparisons of the other ultrasound devices(GE,Siemens,Toshiba),no comparable results could be obtained for any anatomical position of the spleen.The influencing factors age,gender,and body mass index did not show a clear correlation with the measured shear wave velocities.CONCLUSION The absolute values of the shear wave elastography measurements of the spleen and the two different elastography methods are not comparable between different manufacturers or models.展开更多
Two new exact, rational and periodic wave solutions are derived for the two-dimensional Boussinesq equation. For the first solution it is obtained by performing an appropriate limiting procedure on the soliton solutio...Two new exact, rational and periodic wave solutions are derived for the two-dimensional Boussinesq equation. For the first solution it is obtained by performing an appropriate limiting procedure on the soliton solutions obtained by Hirota bilinear method. The second one in terms of Riemann theta function is explicitly presented by virtue of Hirota bilinear method and its asymptotic property is also analyzed in detail. Moreover, it is of interest to note that classical soliton solutions can be reduced from the periodic wave solutions.展开更多
The two-dimensional(2D) pseudo-steady isothermal flow, which is isentropic and irrotational, around a convex corner is studied. The self-similar solutions for the supersonic flow around the convex corner are construct...The two-dimensional(2D) pseudo-steady isothermal flow, which is isentropic and irrotational, around a convex corner is studied. The self-similar solutions for the supersonic flow around the convex corner are constructed, where the properties of the centered simple wave are used for the 2D isentropic irrotational pseudo-steady Euler equations. The geometric procedures of the center simple waves are given. It is proven that the supersonic flow turns the convex corner by an incomplete centered expansion wave or an incomplete centered compression wave, depending on the conditions of the downstream state.展开更多
An analytical solution of the guided wave propagation in a multilayered twodimensional decagonal quasicrystal plate with imperfect interfaces is derived.According to the elastodynamic equations of quasicrystals(QCs),t...An analytical solution of the guided wave propagation in a multilayered twodimensional decagonal quasicrystal plate with imperfect interfaces is derived.According to the elastodynamic equations of quasicrystals(QCs),the wave propagating problem in the plate is converted into a linear control system by employing the state-vector approach,from which the general solutions of the extended displacements and stresses can be obtained,These solutions along the thickness direction are utilized to derive the propagator matrix which connects the physical variables on the lower and upper interfaces of each layer.The special spring model,which describes the discontinuity of the physical quantities across the interface,is introduced into the propagator relationship of the multilayered structure.The total propagator matrix can be used to propagate the solutions in each interface and each layer about the multilayered plate.In addition,the traction-free boundary condition on the top and bottom surfaces of the laminate is considered to obtain the dispersion equation of wave propagation,Finally,typical numerical examples are presented to illustrate the marked influences of stacking sequence and interface coeficients on the dispersion curves and displacement mode shapes of the QC laminates.展开更多
Two-dimensional stress wares in n general incompressible elastic solid are investigated. First, baxic equations for simple wares and shock waves are presented for a general strain energy junction. Then the characteris...Two-dimensional stress wares in n general incompressible elastic solid are investigated. First, baxic equations for simple wares and shock waves are presented for a general strain energy junction. Then the characteristic ware speeds and the associated characteristic vectors are deduced. It is shown that there usually exist two simple waves and two shock wares. Finally, two examples are given for the case of plane strain deformation and antiplane strain deformation, respectively. It is proved that, in the case of plane strain deformation, the oblique reflection problem of a plane shock is not solvable in general.展开更多
Fractures play a crucial role in various fields such as hydrocarbon exploration,groundwater resources management,and earthquake research.The determination of fracture location and the estimation of parameters such as ...Fractures play a crucial role in various fields such as hydrocarbon exploration,groundwater resources management,and earthquake research.The determination of fracture location and the estimation of parameters such as fracture length and dip angle are the focus of geophysical work.In borehole observation system,the short distance between fractures and detectors leads to weak attenuation of elastic wave energy,and high-frequency source makes it easier to identify small-scale fractures.Compared to traditional monopole logging methods,dipole logging method has advantage of exciting pure shear waves sensitive to fractures,so its application is becoming increasingly widespread.However,since the reflected shear waves and scattered shear waves of fractures correspond to different fracture properties,how to distinguish and analyze these two kinds of waves is crucial for accurately characterizing the fracture parameters.To address this issue,numerical simulation of wave responses by a single fracture near a borehole in rock formation is performed,and the generation mechanism and characteristics of shear waves scattered by fractures are investigated.It is found that when the dip angle of the fracture surpasses a critical threshold,the S-wave will propagate to both endpoints of the fracture and generate scattered S-waves,resulting in two distinct scattered wave packets on the received waveform.When the polarization direction of the acoustic source is parallel to the strike of the fracture,the scattered SH-waves always have larger amplitude than the scattered SV-waves regardless of changing the fracture dip angle.Unlike SV-waves,the SH-waves scattered by the fracture do not have any mode conversion.Additionally,propagation of S-waves to a short length fracture can induce dipole mode vibration of the fracture within a wide frequency range.The phenomena of shear waves reflected and scattered by the fracture are further illustrated and verified by two field examples,thus showing the potential of scattered waves for fracture evaluation and characterization with borehole observation system.展开更多
BACKGROUND Shear wave elastography(SWE)is a non-invasive ultrasound-based technique used to assess tissue stiffness,which reflects underlying pathological changes.While SWE has been widely applied for liver fibrosis e...BACKGROUND Shear wave elastography(SWE)is a non-invasive ultrasound-based technique used to assess tissue stiffness,which reflects underlying pathological changes.While SWE has been widely applied for liver fibrosis evaluation,its application to other abdominal organs,such as the spleen and pancreas,is gaining interest.However,normal stiffness values and inter-system agreement remain poorly defined.AIM To assess the feasibility and agreement of liver,spleen,and pancreas stiffness using three SWE methods.METHODS This single-center observational study enrolled 50 healthy adult volunteers.Liver,spleen,and pancreas stiffness were assessed using three SWE methods:Point-SWE(p-QElaXto)and 2-Dimensional-SWE(2D-QElaXto)with Esaote MyLab 9,and 2D-SWE with SuperSonic Imagine.Feasibility,inter-operator reproducibility,and concordance among systems were evaluated.Stiffness was expressed as median kPa values,and technical reliability was assessed using the interquartile range/median ratio and stability index thresholds.RESULTS Liver and spleen stiffness assessment was feasible in>98%of patients,while pancreas stiffness was measurable in 84%-88%depending on the SWE technique.Mean liver stiffness ranged between 3.9-4.7 kPa across techniques,spleen stiffness ranged from 19.4-23.0 kPa,and pancreas stiffness from 5.2-7.6 kPa.Inter-operator agreement was excellent for liver(intraclass correlation coefficient>0.90)and good to moderate for spleen and pancreas(intraclass correlation coefficient from 0.43 to 0.90).Bland-Altman analysis confirmed good correlation but also systematic differences among devices,especially in pancreas measurements.CONCLUSION This is the first study to establish normal liver,spleen,and pancreas stiffness using MyLab 9 SWE integrated methods as compared to SuperSonic Imagine,with acceptable inter-technique agreement.Liver and spleen values matched existing guidelines;pancreas SWE showed more variability and reduced reproducibility.展开更多
Endoscopic ultrasound-guided shear wave elastography(EUS-SWE)represents a significant advancement in non-invasive tissue characterization,enabling objective assessment of quantitative tissue stiffness in real-time wit...Endoscopic ultrasound-guided shear wave elastography(EUS-SWE)represents a significant advancement in non-invasive tissue characterization,enabling objective assessment of quantitative tissue stiffness in real-time with potential clinical relevance across a variety of gastrointestinal disorders.Recent developments in EUS-SWE have expanded its application beyond hepatic fibrosis to include pancreatic diseases and the evaluation of solid tumors.EUS-SWE has demonstrated diagnostic accuracy comparable to vibration-controlled transient elastography in assessing fibrosis stages,positioning it as a potential alternative to liver biopsy.Moreover,EUS-SWE has shown promise in evaluating pancreatic tissue stiffness,aiding in the diagnosis and monitoring of chronic pancreatitis and pancreatic cancer.This technique offers a distinct advantage by allowing tissue stiffness measurements during the same procedure,thereby reducing the need for additional imaging studies and biopsies.Despite its clinical potential,challenges remain,including the need for standardized protocols,optimal cutoff values,and validation across diverse patient populations.This minireview provides a comprehensive analysis of the current literature on EUS-SWE,examining its diagnostic performance,reproducibility,and limitations.Furthermore,we discuss the future directions of EUS-SWE,including its integration into routine clinical practice and its evolving role in precision medicine,emphasizing the necessity of large-scale studies to solidify its clinical utility and establish standardized guidelines for its use.展开更多
The Riemann problem for a two-dimensional 2 x 2 nonstrictly hyperbolic system of nonlinear conservation laws has been solved thoroughly for any given initial data which are constant in each quadrant. The non-classical...The Riemann problem for a two-dimensional 2 x 2 nonstrictly hyperbolic system of nonlinear conservation laws has been solved thoroughly for any given initial data which are constant in each quadrant. The non-classical shockwaves, which are labelled as delta-shock waves, appear in some solutions. The solutions have been obtained are not unique. Due to the specific property of the system considered, there are no rarefaction waves in solution. This paper is divided into three parts. The first part constructs Riemann solutions for initial data involving two contact discontinuities while the second considers the case for other initial data. The last part briefly discusses the non-uniqueness of the solutions.展开更多
This paper investigates the collision between two nonlinear waves with arbitrary angle in two-dimensional nonlinear lattice. By using the extended Poincarge-Lighthill-Kuo perturbation method, it obtains two Korteweg-d...This paper investigates the collision between two nonlinear waves with arbitrary angle in two-dimensional nonlinear lattice. By using the extended Poincarge-Lighthill-Kuo perturbation method, it obtains two Korteweg-de Vries equations for nonlinear waves in both the ζ and η directions, respectively, and derives the analytical phase shifts after the collision of two nonlinear waves. Finally, the solution of u（υ） up to O（ε^3） order is given.展开更多
This paper investigates the collision between two nonlinear waves with different propagation directions in two- dimensional dust crystals. Using the extended Poincare-Lighthill-Kuo perturbation method, two Korteweg-de...This paper investigates the collision between two nonlinear waves with different propagation directions in two- dimensional dust crystals. Using the extended Poincare-Lighthill-Kuo perturbation method, two Korteweg-de Vries equations for nonlinear waves in both the ξ and η directions are obtained, respectively, and the analytical phase shifts and trajectories after the collision of two nonlinear waves are derived. Finally, the effects of parameters of the lattice constant a, the arbitrary constant u0η, the forces f（r）, and the colliding angle θ on the phase shifts of both colliding nonlinear waves are examined.展开更多
基金Supported by Guangdong Medical Science and Technology Research Fund Project,No.A2024475.
文摘This study explores the significance of using two-dimensional shear wave elastography(2D-SWE)to assess liver stiffness(LS)and spleen area(SPA)for predicting post-hepatectomy liver failure(PHLF).By providing a non-invasive method to measure LS,which correlates with the degree of liver fibrosis,and SPA,an indicator of portal hypertension,2D-SWE offers a comprehensive evaluation of a patient’s hepatic status.These advancements are particularly crucial in hepatic surgery,where accurate preoperative assessments are essential for optimizing surgical outcomes and minimizing complications.This letter highlights the prac-tical implications of integrating 2D-SWE into clinical practice,emphasizing its potential to improve patient safety and surgical precision by enhancing the ability to predict PHLF and tailor surgical approaches accordingly.
基金Supported by the Natural Science Foundation of Shanghai,No.22ZR1458200Medical Ph.D Innovative Talent Base Project of Changning District,No.RCJD2021B09+1 种基金Key Specialty of Changning District,No.20231004Shanghai Changning Maternity and Infant Health Hospital Start-Up Project,No.2020Y-14.
文摘BACKGROUND Thyroid dysfunction during pregnancy is an important disease affecting the health of mothers and children.Two-dimensional(2D)shear wave elastography(SWE)is the newest ultrasonic elastography technology and its value in differentiating benign and malignant thyroid nodules has been widely recognized.However,the value of 2D SWE in evaluating and predicting thyroid function is unclear.AIM To explore prospectively the value of 2D SWE quantitative analysis for the evaluation of thyroid function in the first trimester.METHODS We included outpatients of reproductive age in the Department of Gynecology in Shanghai Changning Maternity and Infant Health Hospital between March 2023 and March 2024 who had conventional ultrasound examination and 2D SWE of the thyroid.They also underwent transvaginal ultrasound examination to confirm early intrauterine pregnancy and serum thyroid stimulating hormone(TSH)level was measured.The patients were divided into pregnant with normal TSH,pregnant with abnormal TSH,and nonpregnant with normal TSH.Conventional ultrasound and 2D SWE results were compared among the three groups.RESULTS A total of 108 patients were included in the study;57 in the pregnant with normal TSH group,18 in the pregnant with abnormal TSH group and 33 were in the nonpregnant with normal TSH group.Thyroid size,thyroid echotexture,2D SWE quantitative parameters including mean elasticity in the region of interest and maximal elasticity in the region of interest showed no significant differences among the three groups(P>0.05).CONCLUSION Conventional ultrasound and 2D SWE features could not reflect the level of serum TSH.
基金Supported by Natural Science Foundation of Shanghai of China,No.19ZR1441500,No.22ZR1458200Science Research Foundation of Shanghai Municipal Health Commission,No.202140378Key Program of Science and Technology Commission Foundation of Changning,Shanghai,China,No.CNKW2020Z04.
文摘BACKGROUND The clinical management and prognosis differ between benign and malignant solid focal liver lesions(FLLs),as well as among different pathological types of malignant FLLs.Accurate diagnosis of the possible types of solid FLLs is important.Our previous study confirmed the value of shear wave elastography(SWE)using maximal elasticity(Emax)as the parameter in the differential diagnosis between benign and malignant FLLs.However,the value of SWE in the differential diagnosis among different pathological types of malignant FLLs has not been proved.AIM To explore the value of two-dimensional SWE(2D-SWE)using Emax in the differential diagnosis of FLLs,especially among different pathological types of malignant FLLs.METHODS All the patients enrolled in this study were diagnosed as benign,malignant or undetermined FLLs by conventional ultrasound.Emax of FLLs and the periphery of FLLs was measured using 2D-SWE and compared between benign and malignant FLLs or among different pathological types of malignant FLLs.RESULTS The study included 32 benign FLLs in 31 patients and 100 malignant FLLs in 96 patients,including 16 cholangiocellular carcinomas(CCCs),72 hepatocellular carcinomas(HCCs)and 12 liver metastases.Thirty-five FLLs were diagnosed as undetermined by conventional ultrasound.There were significant differences between Emax of malignant(2.21±0.57 m/s)and benign(1.59±0.37 m/s)FLLs(P=0.000),and between Emax of the periphery of malignant(1.52±0.39 m/s)and benign(1.36±0.44 m/s)FLLs(P=0.040).Emax of liver metastases(2.73±0.99 m/s)was significantly higher than that of CCCs(2.14±0.34 m/s)and HCCs(2.14±0.46 m/s)(P=0.002).The sensitivity,specificity and accuracy were 71.00%,84.38%and 74.24%respectively,using Emax>1.905 m/s(AUC 0.843)to diagnose as malignant and 23 of 35(65.74%)FLLs with undetermined diagnosis by conventional ultrasound were diagnosed correctly.CONCLUSION Malignant FLLs were stiffer than benign ones and liver metastases were stiffer than primary liver carcinomas.2D-SWE with Emax was a useful complement to conventional ultrasound for the differential diagnosis of FLLs.
文摘Two-dimensional shear wave elastography(2D-SWE)is used in the clinical setting for observation of the liver.Unfortunately,a wide spectrum of artifactual images are frequently encountered in 2D-SWE,the precise mechanisms of which remain incompletely understood.This review was designed to present many of the artifactual images seen in 2D-SWE of the liver and to analyze them by computer simulation models that support clinical observations.Our computer simulations yielded the following suggestions:(1)When performing 2D-SWE in patients with chronic hepatic disease,especially liver cirrhosis,it is recommended to measure shear wave values through the least irregular hepatic surface;(2)The most useful 2D-SWE in patients with focal lesion will detect lesions that are poorly visible on B-mode ultrasound and will differentiate true tumors from pseudo-tumors(e.g.,irregular fatty change);and(3)Measurement of shear wave values in the area posterior to a focal lesion must be avoided.
基金National Natural Science Foundation of China,No.81372626Key Research and Development Project of Science and Technology Department of Zhejiang,China,No.2015C03053Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents.
文摘BACKGROUND Post-hepatectomy liver failure(PHLF)increases morbidity and mortality after liver resection for patients with advanced liver fibrosis and cirrhosis.Preoperative liver stiffness using two-dimensional shear wave elastography(2D-SWE)is widely used to evaluate the degree of fibrosis.However,the 2D-SWE results were not accurate.A durometer measures hardness by quantifying the ability of a material to locally resist the intrusion of hard objects into its surface.However,the durometer score can only be obtained during surgery.To measure correlations among 2D-SWE,palpation by surgeons,and durometermeasured objective liver hardness and to construct a liver hardness regression model.METHODS We enrolled 74 hepatectomy patients with liver hardness in a derivation cohort.Tactile-based liver hardness scores(0-100)were determined through palpation of the liver tissue by surgeons.Additionally,liver hardness was measured using a durometer.Correlation coefficients for durometer-measured hardness and preoperative parameters were calculated.Multiple linear regression models were constructed to select the best predictive durometer scale.Receiver operating characteristic(ROC)curves and univariate and multivariate analyses were used to calculate the best model’s prediction of PHLF and risk factors for PHLF,respectively.A separate validation cohort(n=162)was used to evaluate the model.RESULTS The stiffness measured using 2D-SWE and palpation scale had good linear correlation with durometer-measured hardness(Pearson rank correlation coefficient 0.704 and 0.729,respectively,P<0.001).The best model for the durometer scale(hardness scale model)was based on stiffness,hepatitis B virus surface antigen,and albumin level and had an R2 value of 0.580.The area under the ROC for the durometer and hardness scale for PHLF prediction were 0.807(P=0.002)and 0.785(P=0.005),respectively.The optimal cutoff value of the durometer and hardness scale was 27.38(sensitivity=0.900,specificity=0.660)and 27.87(sensitivity=0.700,specificity=0.787),respectively.Patients with a hardness scale score of>27.87 were at a significantly higher risk of PHLF with hazard ratios of 7.835(P=0.015).The model’s PHLF predictive ability was confirmed in the validation cohort.CONCLUSION Liver stiffness assessed by 2D-SWE and palpation correlated well with durometer hardness values.The multiple linear regression model predicted durometer hardness values and PHLF.
文摘Objective:To explore the feasibility of two-dimensional shear wave elastography in evaluating calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome.Methods:A total of 48 diabetic nephropathy patients with medial tibial stress syndrome from January 2020 to December 2022 were included as the study group,and 48 patients with diabetic nephropathy during the same period were included as the control group.Both groups were detected by two-dimensional shear wave elastography with ultrasonic equipment,and Young‘s modulus of the tibialis anterior muscle,tibialis posterior muscle,and gastrocnemius muscle were observed and analyzed in the two groups.Results:The Young‘s modulus values of tibialis anterior muscle,tibialis posterior muscle,and gastrocnemius muscle in the study group were significantly lower than those in the control group(P<0.05).Conclusion:Two-dimensional shear wave elastography is feasible for the evaluation of calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome,and has high accuracy and repeatability.This technique can be used to diagnose,treat and monitor muscle lesions in patients with diabetic nephropathy,and can also be used to assess muscle fatigue and exercise capacity,which has broad application prospects.
文摘Two-dimensional shear wave elastography(2D-SWE) is a rapid, simple and novel noninvasive method that has been proposed for assessing hepatic fibrosis in patients with chronic liver diseases(CLDs) based on measurements of liver stiffness. 2 D-SWE can be performed easily at the bedside or in an outpatient clinic and yields immediate results with good reproducibility. Furthermore, 2 D-SWE was an efficient method for evaluating liver fibrosis in small to moderately sized clinical trials. However, the quality criteria for the staging of liver fibrosis are not yet well defined. Liver fibrosis is the main pathological basis of liver stiffness and a key step in the progression from CLD to cirrhosis; thus, the management of CLD largely depends on the extent and progression of liver fibrosis. 2 D-SWE appears to be an excellent tool for the early detection of cirrhosis and may have prognostic value in this context. Because 2 D-SWE has high patient acceptance, it could be useful for monitoring fibrosis progression and regression in individual cases. However, multicenter data are needed to support its use. This study reviews the current status and future perspectives of 2 D-SWE for assessments of liver fibrosis and discusses the technical advantages and limitations that impact its effective and rational clinical use.
文摘Liver biopsy is the gold standard for evaluating the degree of liver fibrosis in patients with chronic liver disease. However, due to the many limitations of liver biopsy, there has been much interest in the use of noninvasive techniques for this purpose. Among these techniques real-time two-dimensional shear wave elastography(2D-SWE) has the advantage of measuring tissue elasticity with the guidance of B-mode images. Recently, many studies have been conducted on the application of 2D-SWE in patients with various liver diseases, and their validity has been confirmed. Here, we briefly discuss the role of 2D-SWE in patients with chronic liver diseases, particularly aspects of the examination techniques and clinical applications.
基金the National Natural Science Foundation of China(81900594)Clinical Research Plan of Shanghai Hospital Development Center(Grant 16CR3109B)Shanghai Youth Sci&Tech Talent Jump starting Program(18YF1412700).
文摘Background:Liver fibrosis is a common pathological change caused by a variety of etiologies.Early diagnosis and timely treatment can reverse or delay disease progression and improve the prognosis.This study aimed to assess the potential utility of two-dimensional shear wave elastography and texture analysis in dynamic monitoring of the progression of liver fibrosis in rat model.Methods:Twenty rats were divided into control group(n=4)and experimental groups(n=4 per group)with carbon tetrachloride administration for 2,3,4,and 6 weeks.The liver stiffness measurement was performed by two-dimensional shear wave elastography,while the optimal texture analysis subsets to distinguish fibrosis stage were generated by MaZda.The results of elastography and texture analysis were validated through comparing with histopathology.Results:Liver stiffness measurement was 6.09±0.31 kPa in the control group and 7.10±0.41 kPa,7.80±0.93 kPa,8.64±0.93 kPa,9.91±1.13 kPa in the carbon tetrachloride induced groups for 2,3,4,6 weeks,respectively(P<0.05).By texture analysis,histogram and co-occurrence matrix had the most frequency texture parameters in staging liver fibrosis.Receiver operating characteristic curve of liver elasticity showed that the sensitivity and specificity were 95.0%and 92.5%to discriminate liver fibrosis and non-fibrosis,respectively.In texture analysis,five optimal parameters were selected to classify liver fibrosis and non-fibrosis.Conclusions:Two-dimensional shear wave elastography showed potential applications for noninvasive monitoring of the progression of hepatic fibrosis,even in mild fibrosis.Texture analysis can further extract and quantify the texture features in ultrasonic image,which was a supplementary to further visual information and acquired high diagnostic accuracy for severe fibrosis.
文摘BACKGROUND Few systematic comparative studies of the different methods of physical elastography of the spleen are currently available.AIM To compare point shear wave and two-dimensional elastography of the spleen considering the anatomical location(upper,hilar,and lower pole).METHODS As part of a prospective clinical study,healthy volunteers were examined for splenic elasticity using four different ultrasound devices between May 2015 and April 2017.The devices used for point shear wave elastography were from Siemens(S 3000)and Philips(Epiq 7),and those used for two-dimensional shear wave elastography were from GE(Logiq E9)and Toshiba(Aplio 500).In addition,two different software versions(5.0 and 6.0)were evaluated for the Toshiba ultrasound device(Aplio 500).The study consisted of three arms:A,B,and C.RESULTS In study arm A,200 subjects were evaluated(78 males and 122 females,mean age 27.9±8.1 years).In study arm B,113 subjects were evaluated(38 men and 75 women,mean age 26.0±6.3 years).In study arm C,44 subjects were enrolled.A significant correlation of the shear wave velocities at the upper third of the spleen(r=0.33088,P<0.0001)was demonstrated only for the Philips Epiq 7 device compared to the Siemens Acuson S 3000.In comparisons of the other ultrasound devices(GE,Siemens,Toshiba),no comparable results could be obtained for any anatomical position of the spleen.The influencing factors age,gender,and body mass index did not show a clear correlation with the measured shear wave velocities.CONCLUSION The absolute values of the shear wave elastography measurements of the spleen and the two different elastography methods are not comparable between different manufacturers or models.
基金The project supported by National Natural Science Foundation of China under Grant No.10771196the Natural Science Foundation of Zhejiang Province under Grant No.Y605044
文摘Two new exact, rational and periodic wave solutions are derived for the two-dimensional Boussinesq equation. For the first solution it is obtained by performing an appropriate limiting procedure on the soliton solutions obtained by Hirota bilinear method. The second one in terms of Riemann theta function is explicitly presented by virtue of Hirota bilinear method and its asymptotic property is also analyzed in detail. Moreover, it is of interest to note that classical soliton solutions can be reduced from the periodic wave solutions.
基金Project supported by the National Natural Science Foundation of China(Nos.11371240 and11771274)
文摘The two-dimensional(2D) pseudo-steady isothermal flow, which is isentropic and irrotational, around a convex corner is studied. The self-similar solutions for the supersonic flow around the convex corner are constructed, where the properties of the centered simple wave are used for the 2D isentropic irrotational pseudo-steady Euler equations. The geometric procedures of the center simple waves are given. It is proven that the supersonic flow turns the convex corner by an incomplete centered expansion wave or an incomplete centered compression wave, depending on the conditions of the downstream state.
基金supported by the National Natural Science Foundation of China(Grant Nos.11972365,12102458,and 11972354)China Agricultural University Education Foundation(No.1101-2412001).
文摘An analytical solution of the guided wave propagation in a multilayered twodimensional decagonal quasicrystal plate with imperfect interfaces is derived.According to the elastodynamic equations of quasicrystals(QCs),the wave propagating problem in the plate is converted into a linear control system by employing the state-vector approach,from which the general solutions of the extended displacements and stresses can be obtained,These solutions along the thickness direction are utilized to derive the propagator matrix which connects the physical variables on the lower and upper interfaces of each layer.The special spring model,which describes the discontinuity of the physical quantities across the interface,is introduced into the propagator relationship of the multilayered structure.The total propagator matrix can be used to propagate the solutions in each interface and each layer about the multilayered plate.In addition,the traction-free boundary condition on the top and bottom surfaces of the laminate is considered to obtain the dispersion equation of wave propagation,Finally,typical numerical examples are presented to illustrate the marked influences of stacking sequence and interface coeficients on the dispersion curves and displacement mode shapes of the QC laminates.
文摘Two-dimensional stress wares in n general incompressible elastic solid are investigated. First, baxic equations for simple wares and shock waves are presented for a general strain energy junction. Then the characteristic ware speeds and the associated characteristic vectors are deduced. It is shown that there usually exist two simple waves and two shock wares. Finally, two examples are given for the case of plane strain deformation and antiplane strain deformation, respectively. It is proved that, in the case of plane strain deformation, the oblique reflection problem of a plane shock is not solvable in general.
基金supported by Scientific Research and Technology Development Project of CNPC(2024ZG38,2024ZG42)the CNPC Innovation Fund(2022DQ02-0307).
文摘Fractures play a crucial role in various fields such as hydrocarbon exploration,groundwater resources management,and earthquake research.The determination of fracture location and the estimation of parameters such as fracture length and dip angle are the focus of geophysical work.In borehole observation system,the short distance between fractures and detectors leads to weak attenuation of elastic wave energy,and high-frequency source makes it easier to identify small-scale fractures.Compared to traditional monopole logging methods,dipole logging method has advantage of exciting pure shear waves sensitive to fractures,so its application is becoming increasingly widespread.However,since the reflected shear waves and scattered shear waves of fractures correspond to different fracture properties,how to distinguish and analyze these two kinds of waves is crucial for accurately characterizing the fracture parameters.To address this issue,numerical simulation of wave responses by a single fracture near a borehole in rock formation is performed,and the generation mechanism and characteristics of shear waves scattered by fractures are investigated.It is found that when the dip angle of the fracture surpasses a critical threshold,the S-wave will propagate to both endpoints of the fracture and generate scattered S-waves,resulting in two distinct scattered wave packets on the received waveform.When the polarization direction of the acoustic source is parallel to the strike of the fracture,the scattered SH-waves always have larger amplitude than the scattered SV-waves regardless of changing the fracture dip angle.Unlike SV-waves,the SH-waves scattered by the fracture do not have any mode conversion.Additionally,propagation of S-waves to a short length fracture can induce dipole mode vibration of the fracture within a wide frequency range.The phenomena of shear waves reflected and scattered by the fracture are further illustrated and verified by two field examples,thus showing the potential of scattered waves for fracture evaluation and characterization with borehole observation system.
文摘BACKGROUND Shear wave elastography(SWE)is a non-invasive ultrasound-based technique used to assess tissue stiffness,which reflects underlying pathological changes.While SWE has been widely applied for liver fibrosis evaluation,its application to other abdominal organs,such as the spleen and pancreas,is gaining interest.However,normal stiffness values and inter-system agreement remain poorly defined.AIM To assess the feasibility and agreement of liver,spleen,and pancreas stiffness using three SWE methods.METHODS This single-center observational study enrolled 50 healthy adult volunteers.Liver,spleen,and pancreas stiffness were assessed using three SWE methods:Point-SWE(p-QElaXto)and 2-Dimensional-SWE(2D-QElaXto)with Esaote MyLab 9,and 2D-SWE with SuperSonic Imagine.Feasibility,inter-operator reproducibility,and concordance among systems were evaluated.Stiffness was expressed as median kPa values,and technical reliability was assessed using the interquartile range/median ratio and stability index thresholds.RESULTS Liver and spleen stiffness assessment was feasible in>98%of patients,while pancreas stiffness was measurable in 84%-88%depending on the SWE technique.Mean liver stiffness ranged between 3.9-4.7 kPa across techniques,spleen stiffness ranged from 19.4-23.0 kPa,and pancreas stiffness from 5.2-7.6 kPa.Inter-operator agreement was excellent for liver(intraclass correlation coefficient>0.90)and good to moderate for spleen and pancreas(intraclass correlation coefficient from 0.43 to 0.90).Bland-Altman analysis confirmed good correlation but also systematic differences among devices,especially in pancreas measurements.CONCLUSION This is the first study to establish normal liver,spleen,and pancreas stiffness using MyLab 9 SWE integrated methods as compared to SuperSonic Imagine,with acceptable inter-technique agreement.Liver and spleen values matched existing guidelines;pancreas SWE showed more variability and reduced reproducibility.
文摘Endoscopic ultrasound-guided shear wave elastography(EUS-SWE)represents a significant advancement in non-invasive tissue characterization,enabling objective assessment of quantitative tissue stiffness in real-time with potential clinical relevance across a variety of gastrointestinal disorders.Recent developments in EUS-SWE have expanded its application beyond hepatic fibrosis to include pancreatic diseases and the evaluation of solid tumors.EUS-SWE has demonstrated diagnostic accuracy comparable to vibration-controlled transient elastography in assessing fibrosis stages,positioning it as a potential alternative to liver biopsy.Moreover,EUS-SWE has shown promise in evaluating pancreatic tissue stiffness,aiding in the diagnosis and monitoring of chronic pancreatitis and pancreatic cancer.This technique offers a distinct advantage by allowing tissue stiffness measurements during the same procedure,thereby reducing the need for additional imaging studies and biopsies.Despite its clinical potential,challenges remain,including the need for standardized protocols,optimal cutoff values,and validation across diverse patient populations.This minireview provides a comprehensive analysis of the current literature on EUS-SWE,examining its diagnostic performance,reproducibility,and limitations.Furthermore,we discuss the future directions of EUS-SWE,including its integration into routine clinical practice and its evolving role in precision medicine,emphasizing the necessity of large-scale studies to solidify its clinical utility and establish standardized guidelines for its use.
文摘The Riemann problem for a two-dimensional 2 x 2 nonstrictly hyperbolic system of nonlinear conservation laws has been solved thoroughly for any given initial data which are constant in each quadrant. The non-classical shockwaves, which are labelled as delta-shock waves, appear in some solutions. The solutions have been obtained are not unique. Due to the specific property of the system considered, there are no rarefaction waves in solution. This paper is divided into three parts. The first part constructs Riemann solutions for initial data involving two contact discontinuities while the second considers the case for other initial data. The last part briefly discusses the non-uniqueness of the solutions.
基金Project supported by the National Natural Science Foundation of China under (Grant Nos 10575082 and 10247008)the Scientific Research Foundation (SRF) for the Returned Overseas Chinese Scholars (ROCF), State Education Ministry (SEM)
文摘This paper investigates the collision between two nonlinear waves with arbitrary angle in two-dimensional nonlinear lattice. By using the extended Poincarge-Lighthill-Kuo perturbation method, it obtains two Korteweg-de Vries equations for nonlinear waves in both the ζ and η directions, respectively, and derives the analytical phase shifts after the collision of two nonlinear waves. Finally, the solution of u（υ） up to O（ε^3） order is given.
基金Project supported by the National Natural Science Foundation of China(Grant No.10875098)the Scientific and Technical Innovation Foundation of Northwest Normal University(Grant No.NWNU-KJCXGC-0348)
文摘This paper investigates the collision between two nonlinear waves with different propagation directions in two- dimensional dust crystals. Using the extended Poincare-Lighthill-Kuo perturbation method, two Korteweg-de Vries equations for nonlinear waves in both the ξ and η directions are obtained, respectively, and the analytical phase shifts and trajectories after the collision of two nonlinear waves are derived. Finally, the effects of parameters of the lattice constant a, the arbitrary constant u0η, the forces f（r）, and the colliding angle θ on the phase shifts of both colliding nonlinear waves are examined.
