The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical ...The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary effects.As for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with water.It has been observed that the cross-section of the middle part collapses when it reaches the maximum pressure.The collapse pressure obtained from the numerical simulations agrees well with that in the experiment.Meanwhile,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also discussed.It has a relatively greater difference because of the ignorance of the progressive failure of composites.For the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.展开更多
BACKGROUND To date,this is the first case of a paradoxical embolism(PDE)that concurrently manifested in the coronary and lower limb arteries and was secondary to a central venous catheter(CVC)thrombus via a patent for...BACKGROUND To date,this is the first case of a paradoxical embolism(PDE)that concurrently manifested in the coronary and lower limb arteries and was secondary to a central venous catheter(CVC)thrombus via a patent foramen ovale(PFO).CASE SUMMARY Here,we report a case of simultaneous coronary and lower limb artery embolism in a PFO patient carrier of a CVC.The patient presented to the hospital with acute chest pain and lower limb fatigue.Doppler ultrasound showed a large thrombus in the right internal jugular vein,precisely at the tip of the CVC.Transthoracic and transesophageal echocardiography confirmed the existence of a PFO,with inducible right-to-left shunting by the Valsalva maneuver.The patient was administered an extended course of anticoagulation therapy,and then the CVC was successfully removed.Percutaneous PFO closure was not undertaken.There was no recurrence during follow-up.CONCLUSION Thus,CVC-associated thrombosis is a potential source for multiple PDE in PFO patients.展开更多
Background:Transcatheter closure of patent foramen ovale(PFO)has been widely accepted as a highly effective way to treat high-risk PFO-related diseases.However,traditional non-degradable occluders made of metal alloys...Background:Transcatheter closure of patent foramen ovale(PFO)has been widely accepted as a highly effective way to treat high-risk PFO-related diseases.However,traditional non-degradable occluders made of metal alloys will permanently exist in the body,resulting in thrombosis,valve damage,hemolysis,arrhythmia,or other complications.The biodegradable PFO occluder developed by Shanghai Mallow Medical Instrument Co.,Ltd.,China can be fully absorbed and degrade into nontoxic ingredients,reducing postoperative complications.Objectives:To study the safety and efficacy of biodegradable PFO occluders in treating PFO.Methods:This single-center clinical trial collected 30 patients treated with a biodegradable PFO occluder.The follow-up period lasted 12 months to analyze the echocardiographic characteristics and headache relief through HIT-6 scores.Results:The immediate success rate was 100%,with no intraoperative severe occlusion-related complications.The contrast transcranial Doppler(cTCD)at 12 months showed that all patients’right-to-left shunts(RLS)were grade I or 0 with no serious postoperative complications,indicating the overall success rate was 100%.The biodegradable PFO occluder mostly degraded six months after the occlusion.Conclusion:PFO closure with a Mallow biodegradable occluder is safe and effective and has no severe complications.展开更多
Introduction: Platypnea-Orthodeoxia syndrome is characterized by dyspnea and hypoxia in the upright position, usually improving in the supine position. Two components are required: an interatrial or intrapulmonary shu...Introduction: Platypnea-Orthodeoxia syndrome is characterized by dyspnea and hypoxia in the upright position, usually improving in the supine position. Two components are required: an interatrial or intrapulmonary shunt, and a functional component. Diagnosis is made by contrast ultrasonography. We report a case of Platypnea-Orthodeoxia syndrome revealed by positional dyspnea in an 87-year-old patient. The aim of this study is to describe the clinical, therapeutic and evolutionary profile of this syndrome. Case Presentation: This is an 87-year-old patient with a history of pulmonary embolism (PE) and stroke. He was seen for dyspnea and desaturation in orthostatism, revealing a patent foramen ovale (PFO). Progression was favorable after closure of the PFO. Conclusion: Platypnea-Orthodeoxia syndrome may be presented as simple exertional dyspnea. The clinician should check for improvement in symptoms and/or oxygenation during decubitus. Definitive treatment consists of percutaneous closure of the shunt.展开更多
网络安全漏洞扫描应充分考虑执行的效率和信息的共享。本文通过对OVAL和Nessus的介绍,分析O- VAL Definition与Nessus plugin之间的异同,提出并实现了一种将OVAL公布的漏洞信息转换成Nessus扫描插件的方法,共享了漏洞信息,并提升了漏洞...网络安全漏洞扫描应充分考虑执行的效率和信息的共享。本文通过对OVAL和Nessus的介绍,分析O- VAL Definition与Nessus plugin之间的异同,提出并实现了一种将OVAL公布的漏洞信息转换成Nessus扫描插件的方法,共享了漏洞信息,并提升了漏洞检测的品质。最后经过实验说明该方法的可行性。展开更多
In order to improve the efficiency of the Ocean Variational Assimilation System (OVALS), which has been widely used in various applications, an improved OVALS (OVALS2) is developed based on the recursive filter ...In order to improve the efficiency of the Ocean Variational Assimilation System (OVALS), which has been widely used in various applications, an improved OVALS (OVALS2) is developed based on the recursive filter (RF) algorithm. The first advantage of OVALS2 is that memory storage can be substantially reduced in practice because it implicitly computes the background error covariance matrix; the second advantage is that there is no inversion of the background error covariance by preconditioning the control variable. For comparing the effectiveness between OVALS2 and OVALS, a set of experiments was implemented by assimilating expendable bathythermograph (XBT) and ARGO data into the Tropical Pacific circulation model. The results show that the efficiency of OVALS2 is much higher than that of OVALS. The computational time and the computer storage in the assimilation process were reduced by 83% and 77%, respectively. Additionally, the corresponding results produced by the RF are almost as good as those obtained by OVALS. These results prove that OVALS2 is suitable for operational numerical oceanic forecasting.展开更多
The paper deduced a calculation formula by the classic control theory on the Reproducibility Error of parts processing in the technology system,the flexible clamp system, with the clamping device on the gas power,and ...The paper deduced a calculation formula by the classic control theory on the Reproducibility Error of parts processing in the technology system,the flexible clamp system, with the clamping device on the gas power,and analyzed its influencing factor with examples,the Reproducibility Error law:\ The larger the diameter of the cylinder,the smaller the error; the slower the tool speed,(k values smaller),the smaller the error.展开更多
The goal of this study is to propose a method of estimation of bounds for roots of polynomials with complex coefficients. A well-known and easy tool to obtain such information is to use the standard Gershgorin’s theo...The goal of this study is to propose a method of estimation of bounds for roots of polynomials with complex coefficients. A well-known and easy tool to obtain such information is to use the standard Gershgorin’s theorem, however, it doesn’t take into account the structure of the matrix. The modified disks of Gershgorin give the opportunity through some geometrical figures called Ovals of Cassini, to consider the form of the matrix in order to determine appropriated bounds for roots. Furthermore, we have seen that, the Hessenbeg matrices are indicated to estimate good bounds for roots of polynomials as far as we become improved bounds for high values of polynomial’s coefficients. But the bounds are better for small values. The aim of the work was to take advantages of this, after introducing the Dehmer’s bound, to find an appropriated property of the Hessenberg form. To illustrate our results, illustrative examples are given to compare the obtained bounds to those obtained through classical methods like Cauchy’s bounds, Montel’s bounds and Carmichel-Mason’s bounds.展开更多
AIM To detect immunohistochemically the presence of oval cells in chronic viral hepatitis with antibody against c-kit.METHODS We detected oval cells in paraffin-embedded liver sections of 3 normal controls and 26 live...AIM To detect immunohistochemically the presence of oval cells in chronic viral hepatitis with antibody against c-kit.METHODS We detected oval cells in paraffin-embedded liver sections of 3 normal controls and 26 liver samples from patients with chronic viral hepatitis, using immunohistochemistry with antibodies against c-kit, π-class glutathione Stransferase ( Tr-GST ) and cytokeratins 19(CK19).RESULTS Oval cells were not observed in normal livers. In chronic viral hepatitis, hepatic oval cells were located predominantly in the periportal . region and fibrosis septa,characterized by an ovoid nucleus, small size,and scant cytoplasm. Antibody against stem cell factor receptor, c-kit, had higher sensitivity and specificity than π-GST and CK19. About 50% -70% of c-kit positive oval cells were stained positively for either π-GST or CK19.CONCLUSION Oval cells are frequently detected in human livers with chronic viral hepatitis, suggesting that oval cell proliferation is associated with the liver regeneration in this condition.展开更多
Three dimensional thermal-mechanical coupled elasto-plastic FEM has been used for simulation of round to oval single pass rolling. The analysis was conducted using MARC/AUTOFORCE1. 2 code. The material is assumed to b...Three dimensional thermal-mechanical coupled elasto-plastic FEM has been used for simulation of round to oval single pass rolling. The analysis was conducted using MARC/AUTOFORCE1. 2 code. The material is assumed to be elasto-plastic and it obey the Von Mises yield criterion and Prandtl- Reuss rule. Deformation of the workpiece is simulated in a step-by-step manner,updating the coordinates of material points and the property after each step, so that both nonsteady-state and stendy-state deformation can be simulated. The heat transfter between the workpiece, the rolls, and enviroment and the heat generation due to plastic work and friction force, are considered in the analys- is.Predicted the deformation shape of the workpiece, distributions of strains, stresses, strain rates and temperatures, roll-separating force and roll torque are presented.展开更多
AIM To investigate if patent foramen ovale(PFO) closure device reduces the risk of recurrent stroke in patients with cryptogenic stroke.METHODS We searched five databases-Pub Med,EMBASE,Cochrane,CINAHL and Web-of-Scie...AIM To investigate if patent foramen ovale(PFO) closure device reduces the risk of recurrent stroke in patients with cryptogenic stroke.METHODS We searched five databases-Pub Med,EMBASE,Cochrane,CINAHL and Web-of-Science and clinicaltrials.gov from January 2000 to September 2017 for randomized trials comparing PFO closure to medical therapy in cryptogenic stroke.Heterogeneity was determined using Cochrane's Q statistics.Random effects model was used.RESULTS Five randomized controlled trials with 3440 patients were included in the analysis.Mean follow-up was 50 ± 20 mo.PFO closure was associated with a 41% reduction in incidence of recurrent strokes when compared to medical therapy alone in patients with cryptogenic stroke [risk ratio(RR): 0.59,95%CI: 0.40-0.87,P = 0.008].Atrial fibrillation was higher with device closure when compared to medical therapy alone(RR: 4.97,95%CI: 2.22-11.11,P < 0.001).There was no difference between the two groups with respect to all-cause mortality,major bleeding or adverse events.CONCLUSION PFO device closure in appropriately selected patients with moderate to severe right-to-left shunt and/or atrial septal aneurysm shows benefit with respect to recurrent strokes,particularly in younger patients.Further studies are essential to evaluate the impact of higher incidence of atrial fibrillation seen with the PFO closure device on long-term mortality and stroke rates.展开更多
Non-invasive Doppler ultrasonographic study of cerebral arteries [transcranial Doppler(TCD)] has been extensively applied on both outpatient and inpatient settings. It is performed placing a low-frequency(≤ 2 MHz) tr...Non-invasive Doppler ultrasonographic study of cerebral arteries [transcranial Doppler(TCD)] has been extensively applied on both outpatient and inpatient settings. It is performed placing a low-frequency(≤ 2 MHz) transducer on the scalp of the patient over specific acoustic windows, in order to visualize the intracranial arterial vessels and to evaluate the cerebral blood flow velocity and its alteration in many different conditions. Nowadays the most widespread indication for TCD in outpatient setting is the research of right to left shunting, responsable of so called "paradoxical embolism", most often due to patency of foramen ovale which is responsable of the majority of cryptogenic strokes occuring in patients younger than 55 years old. TCD also allows to classify the grade of severity of such shunts using the so called "microembolic signal grading score". In addition TCD has found many useful applications in neurocritical care practice. It is useful on both adults and children for day-to-day bedside assessment of critical conditions including vasospasm in subarachnoidal haemorrhage(caused by aneurysm rupture or traumatic injury), traumatic brain injury, brain stem death. It is used also to evaluate cerebral hemodynamic changes after stroke. It also allows to investigate cerebral pressure autoregulation and for the clinical evaluation of cerebral autoregulatory reserve.展开更多
AIM To test the potential association between atrial septal aneurysm(ASA) and migraine in patent foramen ovale(PFO) closure patients through an observational, singlecenter, case-controlled study.METHODS We studied a t...AIM To test the potential association between atrial septal aneurysm(ASA) and migraine in patent foramen ovale(PFO) closure patients through an observational, singlecenter, case-controlled study.METHODS We studied a total of 450 migraineurs who had rightto-left shunts and underwent PFO closure in a retrospective single-center non-randomized registry from February 2012 to October 2016 on the condition that they were aged 18-45 years old. Migraine was diagnosed according to the International Classification of Headache Disorders, 3^(rd) edition and evaluated using the Headache Impact Test-6(HIT-6). All patients underwent preoperative transesophageal echocardiography, contrast transthoracic echocardiography, and computed tomography or magnetic resonance imaging examinations, with subsequent fluoroscopy-guided PFO closure. Based on whether they have ASA or not, the patients were divided into two groups: A(PFO with ASA, n = 80) and B(PFO without ASA, n = 370). Baseline characteristics and procedural and follow-up data were reviewed. RESULTS Compared to group B, group A had an increased frequency of ischemic lesions(11.3% vs 6.2%, P = 0.038) and migraine with aura(32.5% vs 21.1%, P = 0.040). The PFO size was significantly larger in group A(P = 0.007). There was no significant difference in HIT-6 scores between the two groups before and at the oneyear follow-up after the PFO closure [61(9) vs 63(9), P = 0.227; 36(13) vs 36(10), P = 0.706].CONCLUSION Despite its small sample size, our study suggests that the prevalence of ASA in PFO with migraine patients is associated with ischemic stroke, larger PFO size, and migraine with aura.展开更多
基金financially supported by National Natural Science Foundation of China(Grant Nos.52088102,51879249)Fundamental Research Funds for the Central Universities(Grant No.202261055)。
文摘The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary effects.As for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with water.It has been observed that the cross-section of the middle part collapses when it reaches the maximum pressure.The collapse pressure obtained from the numerical simulations agrees well with that in the experiment.Meanwhile,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also discussed.It has a relatively greater difference because of the ignorance of the progressive failure of composites.For the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.
基金Supported by Natural Science Foundation of Guangdong Province,No.2021A1515011267and Guangzhou Municipal Science and Technology Bureau,No.2023A03J0984.
文摘BACKGROUND To date,this is the first case of a paradoxical embolism(PDE)that concurrently manifested in the coronary and lower limb arteries and was secondary to a central venous catheter(CVC)thrombus via a patent foramen ovale(PFO).CASE SUMMARY Here,we report a case of simultaneous coronary and lower limb artery embolism in a PFO patient carrier of a CVC.The patient presented to the hospital with acute chest pain and lower limb fatigue.Doppler ultrasound showed a large thrombus in the right internal jugular vein,precisely at the tip of the CVC.Transthoracic and transesophageal echocardiography confirmed the existence of a PFO,with inducible right-to-left shunting by the Valsalva maneuver.The patient was administered an extended course of anticoagulation therapy,and then the CVC was successfully removed.Percutaneous PFO closure was not undertaken.There was no recurrence during follow-up.CONCLUSION Thus,CVC-associated thrombosis is a potential source for multiple PDE in PFO patients.
基金supported by the Health and Family Planning Commission of Wuhan Municipality,Grant WX21Z26.
文摘Background:Transcatheter closure of patent foramen ovale(PFO)has been widely accepted as a highly effective way to treat high-risk PFO-related diseases.However,traditional non-degradable occluders made of metal alloys will permanently exist in the body,resulting in thrombosis,valve damage,hemolysis,arrhythmia,or other complications.The biodegradable PFO occluder developed by Shanghai Mallow Medical Instrument Co.,Ltd.,China can be fully absorbed and degrade into nontoxic ingredients,reducing postoperative complications.Objectives:To study the safety and efficacy of biodegradable PFO occluders in treating PFO.Methods:This single-center clinical trial collected 30 patients treated with a biodegradable PFO occluder.The follow-up period lasted 12 months to analyze the echocardiographic characteristics and headache relief through HIT-6 scores.Results:The immediate success rate was 100%,with no intraoperative severe occlusion-related complications.The contrast transcranial Doppler(cTCD)at 12 months showed that all patients’right-to-left shunts(RLS)were grade I or 0 with no serious postoperative complications,indicating the overall success rate was 100%.The biodegradable PFO occluder mostly degraded six months after the occlusion.Conclusion:PFO closure with a Mallow biodegradable occluder is safe and effective and has no severe complications.
文摘Introduction: Platypnea-Orthodeoxia syndrome is characterized by dyspnea and hypoxia in the upright position, usually improving in the supine position. Two components are required: an interatrial or intrapulmonary shunt, and a functional component. Diagnosis is made by contrast ultrasonography. We report a case of Platypnea-Orthodeoxia syndrome revealed by positional dyspnea in an 87-year-old patient. The aim of this study is to describe the clinical, therapeutic and evolutionary profile of this syndrome. Case Presentation: This is an 87-year-old patient with a history of pulmonary embolism (PE) and stroke. He was seen for dyspnea and desaturation in orthostatism, revealing a patent foramen ovale (PFO). Progression was favorable after closure of the PFO. Conclusion: Platypnea-Orthodeoxia syndrome may be presented as simple exertional dyspnea. The clinician should check for improvement in symptoms and/or oxygenation during decubitus. Definitive treatment consists of percutaneous closure of the shunt.
文摘网络安全漏洞扫描应充分考虑执行的效率和信息的共享。本文通过对OVAL和Nessus的介绍,分析O- VAL Definition与Nessus plugin之间的异同,提出并实现了一种将OVAL公布的漏洞信息转换成Nessus扫描插件的方法,共享了漏洞信息,并提升了漏洞检测的品质。最后经过实验说明该方法的可行性。
基金supported by the Chinese Academy of Science(Contract No. KZCX2-YW-202)the 973 Pro-gram (Grant No. 2006CB403606)the National Natural Science Foundation of China (Grant Nos. 40606008,40776011)
文摘In order to improve the efficiency of the Ocean Variational Assimilation System (OVALS), which has been widely used in various applications, an improved OVALS (OVALS2) is developed based on the recursive filter (RF) algorithm. The first advantage of OVALS2 is that memory storage can be substantially reduced in practice because it implicitly computes the background error covariance matrix; the second advantage is that there is no inversion of the background error covariance by preconditioning the control variable. For comparing the effectiveness between OVALS2 and OVALS, a set of experiments was implemented by assimilating expendable bathythermograph (XBT) and ARGO data into the Tropical Pacific circulation model. The results show that the efficiency of OVALS2 is much higher than that of OVALS. The computational time and the computer storage in the assimilation process were reduced by 83% and 77%, respectively. Additionally, the corresponding results produced by the RF are almost as good as those obtained by OVALS. These results prove that OVALS2 is suitable for operational numerical oceanic forecasting.
基金Tianjin Nature Science Date(08JCYBJC 11700) "CAD System of Fixture on New Fixture Design Theory of Accuracy Design"
文摘The paper deduced a calculation formula by the classic control theory on the Reproducibility Error of parts processing in the technology system,the flexible clamp system, with the clamping device on the gas power,and analyzed its influencing factor with examples,the Reproducibility Error law:\ The larger the diameter of the cylinder,the smaller the error; the slower the tool speed,(k values smaller),the smaller the error.
文摘The goal of this study is to propose a method of estimation of bounds for roots of polynomials with complex coefficients. A well-known and easy tool to obtain such information is to use the standard Gershgorin’s theorem, however, it doesn’t take into account the structure of the matrix. The modified disks of Gershgorin give the opportunity through some geometrical figures called Ovals of Cassini, to consider the form of the matrix in order to determine appropriated bounds for roots. Furthermore, we have seen that, the Hessenbeg matrices are indicated to estimate good bounds for roots of polynomials as far as we become improved bounds for high values of polynomial’s coefficients. But the bounds are better for small values. The aim of the work was to take advantages of this, after introducing the Dehmer’s bound, to find an appropriated property of the Hessenberg form. To illustrate our results, illustrative examples are given to compare the obtained bounds to those obtained through classical methods like Cauchy’s bounds, Montel’s bounds and Carmichel-Mason’s bounds.
文摘AIM To detect immunohistochemically the presence of oval cells in chronic viral hepatitis with antibody against c-kit.METHODS We detected oval cells in paraffin-embedded liver sections of 3 normal controls and 26 liver samples from patients with chronic viral hepatitis, using immunohistochemistry with antibodies against c-kit, π-class glutathione Stransferase ( Tr-GST ) and cytokeratins 19(CK19).RESULTS Oval cells were not observed in normal livers. In chronic viral hepatitis, hepatic oval cells were located predominantly in the periportal . region and fibrosis septa,characterized by an ovoid nucleus, small size,and scant cytoplasm. Antibody against stem cell factor receptor, c-kit, had higher sensitivity and specificity than π-GST and CK19. About 50% -70% of c-kit positive oval cells were stained positively for either π-GST or CK19.CONCLUSION Oval cells are frequently detected in human livers with chronic viral hepatitis, suggesting that oval cell proliferation is associated with the liver regeneration in this condition.
文摘Three dimensional thermal-mechanical coupled elasto-plastic FEM has been used for simulation of round to oval single pass rolling. The analysis was conducted using MARC/AUTOFORCE1. 2 code. The material is assumed to be elasto-plastic and it obey the Von Mises yield criterion and Prandtl- Reuss rule. Deformation of the workpiece is simulated in a step-by-step manner,updating the coordinates of material points and the property after each step, so that both nonsteady-state and stendy-state deformation can be simulated. The heat transfter between the workpiece, the rolls, and enviroment and the heat generation due to plastic work and friction force, are considered in the analys- is.Predicted the deformation shape of the workpiece, distributions of strains, stresses, strain rates and temperatures, roll-separating force and roll torque are presented.
文摘AIM To investigate if patent foramen ovale(PFO) closure device reduces the risk of recurrent stroke in patients with cryptogenic stroke.METHODS We searched five databases-Pub Med,EMBASE,Cochrane,CINAHL and Web-of-Science and clinicaltrials.gov from January 2000 to September 2017 for randomized trials comparing PFO closure to medical therapy in cryptogenic stroke.Heterogeneity was determined using Cochrane's Q statistics.Random effects model was used.RESULTS Five randomized controlled trials with 3440 patients were included in the analysis.Mean follow-up was 50 ± 20 mo.PFO closure was associated with a 41% reduction in incidence of recurrent strokes when compared to medical therapy alone in patients with cryptogenic stroke [risk ratio(RR): 0.59,95%CI: 0.40-0.87,P = 0.008].Atrial fibrillation was higher with device closure when compared to medical therapy alone(RR: 4.97,95%CI: 2.22-11.11,P < 0.001).There was no difference between the two groups with respect to all-cause mortality,major bleeding or adverse events.CONCLUSION PFO device closure in appropriately selected patients with moderate to severe right-to-left shunt and/or atrial septal aneurysm shows benefit with respect to recurrent strokes,particularly in younger patients.Further studies are essential to evaluate the impact of higher incidence of atrial fibrillation seen with the PFO closure device on long-term mortality and stroke rates.
文摘Non-invasive Doppler ultrasonographic study of cerebral arteries [transcranial Doppler(TCD)] has been extensively applied on both outpatient and inpatient settings. It is performed placing a low-frequency(≤ 2 MHz) transducer on the scalp of the patient over specific acoustic windows, in order to visualize the intracranial arterial vessels and to evaluate the cerebral blood flow velocity and its alteration in many different conditions. Nowadays the most widespread indication for TCD in outpatient setting is the research of right to left shunting, responsable of so called "paradoxical embolism", most often due to patency of foramen ovale which is responsable of the majority of cryptogenic strokes occuring in patients younger than 55 years old. TCD also allows to classify the grade of severity of such shunts using the so called "microembolic signal grading score". In addition TCD has found many useful applications in neurocritical care practice. It is useful on both adults and children for day-to-day bedside assessment of critical conditions including vasospasm in subarachnoidal haemorrhage(caused by aneurysm rupture or traumatic injury), traumatic brain injury, brain stem death. It is used also to evaluate cerebral hemodynamic changes after stroke. It also allows to investigate cerebral pressure autoregulation and for the clinical evaluation of cerebral autoregulatory reserve.
文摘AIM To test the potential association between atrial septal aneurysm(ASA) and migraine in patent foramen ovale(PFO) closure patients through an observational, singlecenter, case-controlled study.METHODS We studied a total of 450 migraineurs who had rightto-left shunts and underwent PFO closure in a retrospective single-center non-randomized registry from February 2012 to October 2016 on the condition that they were aged 18-45 years old. Migraine was diagnosed according to the International Classification of Headache Disorders, 3^(rd) edition and evaluated using the Headache Impact Test-6(HIT-6). All patients underwent preoperative transesophageal echocardiography, contrast transthoracic echocardiography, and computed tomography or magnetic resonance imaging examinations, with subsequent fluoroscopy-guided PFO closure. Based on whether they have ASA or not, the patients were divided into two groups: A(PFO with ASA, n = 80) and B(PFO without ASA, n = 370). Baseline characteristics and procedural and follow-up data were reviewed. RESULTS Compared to group B, group A had an increased frequency of ischemic lesions(11.3% vs 6.2%, P = 0.038) and migraine with aura(32.5% vs 21.1%, P = 0.040). The PFO size was significantly larger in group A(P = 0.007). There was no significant difference in HIT-6 scores between the two groups before and at the oneyear follow-up after the PFO closure [61(9) vs 63(9), P = 0.227; 36(13) vs 36(10), P = 0.706].CONCLUSION Despite its small sample size, our study suggests that the prevalence of ASA in PFO with migraine patients is associated with ischemic stroke, larger PFO size, and migraine with aura.