Cerebral autoregulation(CA)is the mechanism that maintains stable cerebral blood flow(CBF)despite fluctuations in systemic blood pressure,crucial for brain homeostasis.Recent evidence highlights distinct regional vari...Cerebral autoregulation(CA)is the mechanism that maintains stable cerebral blood flow(CBF)despite fluctuations in systemic blood pressure,crucial for brain homeostasis.Recent evidence highlights distinct regional variations in CA between the anterior(carotid)and posterior(vertebrobasilar)circulations.Noninvasive neuromonitoring techniques,such as transcranial Doppler,transfer function analysis,and near-infrared spectroscopy,facilitate the dynamic assessment of CBF and autoregulation.Studies indicate a robust autoregulatory capacity in the anterior circulation,characterized by rapid adjustments in vascular resistance.On the contrary,the posterior circulation,mainly supplied by the vertebral arteries,may have a lower autoregulatory capacity.in acute brain injuries such as intracerebral and subarachnoid hemorrhage,and traumatic brain injuries,dynamic CA can be significantly altered in the posterior circulation.Proposed physiological mechanisms of impaired CA in the posterior circulation include:(1)Decreased sympathetic innervation of the vasculature impairing compensatory vasoreactivity;(2)Endothelial dysfunction;(3)Increased cerebral metabolic rate of oxygen consumption within the visual cortex causing CBFmetabolism(i.e.,neurovascular)uncoupling;and(4)Impaired blood-brain barrier integrity leading to impaired astrocytic mediated release of vasoactive substances(e.g.nitric oxide,potassium,and calcium ions).Furthermore,more research is needed on the effects of collateral circulation,as well as the circle of Willis variants,such as the fetal-type posterior cerebral artery,on dynamic CA.Improving our understanding of these mechanisms is crucial to improving the diagnosis,prognosis,and management of various cerebrovascular disorders.展开更多
Objective:For patients with early acute cerebral infarction(ACI),transcranial Doppler ultrasound was used in the clinical examination,and its application effect was observed and analyzed.Methods:This study was carried...Objective:For patients with early acute cerebral infarction(ACI),transcranial Doppler ultrasound was used in the clinical examination,and its application effect was observed and analyzed.Methods:This study was carried out between October 2018 and October 2019.50 patients with ACI included as the research object was evaluated by transcranial Doppler and CT examination,and the application of the two examination methods was compared.Results:The results of transcranial Doppler examination showed that the abnormal rate of blood flow velocity and the ratio of both sides(VACA)in patients with early ACI was higher than that of CT examination.Conclusion:With the impact on the location and area of vascular occlusion in patients,VACA can effectively reflect the status and effectiveness of the collateral circulation function of the patient’s pia vessels during cerebral infarction.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
Objective To explore the effect of locally using dexamethasone on the blood flow velocity in the middle cerebral artery(FVmca) and cerebral edema after brain injury. Methods 20 rabbits were classified to 2 groups, gro...Objective To explore the effect of locally using dexamethasone on the blood flow velocity in the middle cerebral artery(FVmca) and cerebral edema after brain injury. Methods 20 rabbits were classified to 2 groups, group A( the control group) and B (the treated group). An experimental rabbit model was conducted to contusion by bone window plasty with extradural hitting. Group B was treated by locally infiltrating of dexamethasone at equidistance to lesions. Group A was given normal saline the same way as Group B. The changes of FVmca using trans－cranial Doppler and moisture in brain tissues were observed. Results The normal value of FVmca was (31.8± 4.5)cm/s, while the value of FVmca in group A and B were (15.4± 3.9)cm/s and (22.1± 3.5)cm/s separately.Water content in damaged hemisphere in Group A and B were (81.54± 0.55)％ and (79.35± 0.50)％ respectively. There was a significant difference between the 2 groups (P<0.05). The levels of FVmca in group A and B were lower than that of control and there was also a significant difference between group A and B (P<0.05).Conclusions FVmca decreased and the brain moisture increased after brain injury while FVmca increased and the brain moisture reduced after treatment with dexamethasone. It demonstreated that local treatment of dexamethasone had an obvious therapeutical effect on brain injury.展开更多
BACKGROUND: With the development of interventional therapy, it is necessary for evaluating cerebral vessels to instruct treatment and determine prognosis of patients with ischemic stroke; however, correlation of distr...BACKGROUND: With the development of interventional therapy, it is necessary for evaluating cerebral vessels to instruct treatment and determine prognosis of patients with ischemic stroke; however, correlation of distribution of infarction focus and clinical symptoms with degrees of cerebrovascular stricture is still unclear. OBJECTIVE: To evaluate the characteristics of cerebral arterial stricture of patients with ischemic stroke with transcranial Doppler (TCD) and color duplex flow imaging (CDFI) and compare the correlation between distribution of cerebral infarction focus and clinical types with magnetic resonance imaging (MRI). DESIGN: Contrast observation. SETTING: Department of Neurology, the First Hospital of Jilin University. PARTICIPANTS: A total of 159 patients with ischemic stroke were selected from the Department of Neurology, the First Hospital of Jilin University from January to December 2005, including 106 males and 53 females aged from 27 to 88 years. Bases on diagnostic criteria of cerebrovascular disease established by Rao et al, clinical manifestations of all patients were evaluated with CT or nuclear magnetic resonance. All patients provided the confirmed consent. METHODS: The accepted patients received TCD and CDFI examination at 1 week after onset of ischemic stroke. Among them, 112 patients received cerebrovascular imaging examination simultaneously. MRI was used to check cerebral infarction focus and cerebrovascular stricture > 50% was regarded as the accepted vessels. In addition, DWI-T2 TCD (Germany) was used to check middle cerebral artery, and degrees of middle cerebral artery were classified into mild, moderate and severe stricture based on blood velocity (140 cm/s, 180 cm/s). Stroke was classified based on characteristics of infarction focus and clinical symptoms showed with MRI and correlation with degrees of cerebrovascular stricture was analyzed simultaneously. MAIN OUTCOME MEASURES: Correlation between the characteristics of ischemic stroke and clinical symptoms checked with TCD and CDFI. RESULTS: A total of 159 patients with ischemic stroke were involved in the final analysis; in addition, 112 cases received cerebrovascular imaging examination simultaneously. ① MRI results of 159 patients with cerebral artery occlusive disease (CAOD): There were 131 patients (82.3%) with cerebral infarction, 40 (25.2%) with transient ischemic attack and 4 (2.5%) with subclavian steal syndrome (SSS). ② Infarction types with MRI examination: There were 33 patients (20.8%) with solitary cerebral infarction and 98 (61.6%) with multiple-cerebral infarction. ③ Results of TCD, CDFI, MRI angiography, CT angiography and digital subtraction angiography (DSA): Among 112 patients, 181 lesion sites (61.8%) were located in cranium and 112 lesion sites were located out of cranium; especially, lesion site was mostly observed in stem of middle cerebral artery (31.2%) and watershed of basilar artery (7.2%) in cranium and the beginning site of internal carotid artery (21.4%) out of cranium. ④ Correlation of vascular stricture checking with TCD, MRI and clinical diagnosis: On one hand, MRI and clinical diagnosis demonstrated that 68 patients had a watershed infarction; meanwhile, TCD examination indicated that there were 3 patients with mild vascular stricture, 24 with moderate vascular stricture and 36 with severe vascular stricture. On the other hand, among 68 patients with non-watershed infarction, there were 27 patient with mild vascular stricture, 26 with moderate vascular stricture and 15 with severe vascular stricture. There were significant differences (χ2 =26.854, P =0.001). Clinical diagnosis indicated that 40 patients had transient ischemic attack and TCD examination demonstrated that there were 8 patient with mild vascular stricture, 12 with moderate vascular stricture and 20 with severe vascular stricture. There were significant differences as compared with 68 patients with watershed infarction (χ2 =21.258, P =0.001). ⑤ Correlation of vascular stricture checking with CDFI, MRI and clinical diagnosis: On one hand, among patients who were determined as watershed infarction with MRI and clinical diagnosis, CDFI examination indicated that there were 32 patients with mild vascular stricture at neck, 25 with moderate vascular stricture and 6 with severe vascular stricture. On the other hand, among patients with non-watershed infarction, there were 48 patient with mild vascular stricture, 18 with moderate vascular stricture and 2 with severe vascular stricture. There were significant differences (χ2 =6.018, P =0.019). Among patients with transient ischemic attack checking with clinical diagnosis, there were 23 patient with mild vascular stricture, 9 with moderate vascular stricture and 8 with severe vascular stricture. There were no significant differences as compared with patients with non-watershed infarction (χ2 =0.597, P =0.440). CONCLUSION: ① TCD and CDFI are effective marks to determine cerebral arterial stricture and hemodynamical changes. ② Infarction and transient ischemic attack at watershed are generally clinical phenotypes of CAOD patients and infarction at watershed is correlated with degrees of cerebrovascular stricture. ③ TCD, MRI and clinical analysis of stroke types are significant for instructing treatment and evaluate prognosis.展开更多
Objective: To evaluate the assessment of intracranial hypertension and nerve injury in patients with hypertensive cerebral hemorrhage by transcranial Doppler (TCD). Methods: The patients who were hospitalized for hype...Objective: To evaluate the assessment of intracranial hypertension and nerve injury in patients with hypertensive cerebral hemorrhage by transcranial Doppler (TCD). Methods: The patients who were hospitalized for hypertensive cerebral hemorrhage between August 2014 and February 2017 were selected as the cerebral hemorrhage group and healthy subjects who received physical examination during the same period were selected as the control group;TCD was used to determine the PI of affected-side and unaffected-side middle cerebral artery in cerebral hemorrhage group and lumbar puncture was done to measure intracranial pressure. The serum was collected from the two groups to detect the levels of inflammatory cytokines and nerve injury markers. Results: PI level in affected-side middle cerebral artery of cerebral hemorrhage group was significantly higher than that in the unaffected-side and positively correlated with intracranial pressure level;serum IL-1β, TNF-α, ICAM-1, MMP9, YKL-40, Asp, Glu, NPY, NSE and GFAP levels of cerebral hemorrhage group were significantly higher than those of control group, and serum IL-1β, TNF-α, ICAM-1, MMP9, YKL-40, Asp, Glu, NPY, NSE and GFAP levels of cerebral hemorrhage group of patients with high PI level were significantly higher than those of cerebral hemorrhage group of patients with low PI level. Conclusion: TCD parameters can evaluate the degree of intracranial pressure increase and nerve injury in patients with hypertensive cerebral hemorrhage.展开更多
[SUMMARY] TTTT is a non-invasive and new investigative examination,and a most important method of clinical diagnosis for many diseases,specially for orthostatic syncope,autonomic failure,intracranial hypertension,neur...[SUMMARY] TTTT is a non-invasive and new investigative examination,and a most important method of clinical diagnosis for many diseases,specially for orthostatic syncope,autonomic failure,intracranial hypertension,neurodegenerative diseases,CVAs and so on.At the same time,TCD technique for non-invasive monitoring of CBFV has also provided a new tool for investigating CA.In clinical circumstance,we may carry on assessment of dynamic CA by TTTT,and this kind of method has been proved to be appropriate to examine patients and monitor.we can choose different tilt positions by tilt-table according to the different demands for clinical diagnosis or researches,and record the different appearances of various index signs,we can take advantage of the technique of transfer function analysis of power spectrum between spontaneous changes in CBF and other factors(such as arterial pressure) to do research on the specific mechanism of impaired CA.展开更多
文摘Cerebral autoregulation(CA)is the mechanism that maintains stable cerebral blood flow(CBF)despite fluctuations in systemic blood pressure,crucial for brain homeostasis.Recent evidence highlights distinct regional variations in CA between the anterior(carotid)and posterior(vertebrobasilar)circulations.Noninvasive neuromonitoring techniques,such as transcranial Doppler,transfer function analysis,and near-infrared spectroscopy,facilitate the dynamic assessment of CBF and autoregulation.Studies indicate a robust autoregulatory capacity in the anterior circulation,characterized by rapid adjustments in vascular resistance.On the contrary,the posterior circulation,mainly supplied by the vertebral arteries,may have a lower autoregulatory capacity.in acute brain injuries such as intracerebral and subarachnoid hemorrhage,and traumatic brain injuries,dynamic CA can be significantly altered in the posterior circulation.Proposed physiological mechanisms of impaired CA in the posterior circulation include:(1)Decreased sympathetic innervation of the vasculature impairing compensatory vasoreactivity;(2)Endothelial dysfunction;(3)Increased cerebral metabolic rate of oxygen consumption within the visual cortex causing CBFmetabolism(i.e.,neurovascular)uncoupling;and(4)Impaired blood-brain barrier integrity leading to impaired astrocytic mediated release of vasoactive substances(e.g.nitric oxide,potassium,and calcium ions).Furthermore,more research is needed on the effects of collateral circulation,as well as the circle of Willis variants,such as the fetal-type posterior cerebral artery,on dynamic CA.Improving our understanding of these mechanisms is crucial to improving the diagnosis,prognosis,and management of various cerebrovascular disorders.
文摘Objective:For patients with early acute cerebral infarction(ACI),transcranial Doppler ultrasound was used in the clinical examination,and its application effect was observed and analyzed.Methods:This study was carried out between October 2018 and October 2019.50 patients with ACI included as the research object was evaluated by transcranial Doppler and CT examination,and the application of the two examination methods was compared.Results:The results of transcranial Doppler examination showed that the abnormal rate of blood flow velocity and the ratio of both sides(VACA)in patients with early ACI was higher than that of CT examination.Conclusion:With the impact on the location and area of vascular occlusion in patients,VACA can effectively reflect the status and effectiveness of the collateral circulation function of the patient’s pia vessels during cerebral infarction.
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Objective To explore the effect of locally using dexamethasone on the blood flow velocity in the middle cerebral artery(FVmca) and cerebral edema after brain injury. Methods 20 rabbits were classified to 2 groups, group A( the control group) and B (the treated group). An experimental rabbit model was conducted to contusion by bone window plasty with extradural hitting. Group B was treated by locally infiltrating of dexamethasone at equidistance to lesions. Group A was given normal saline the same way as Group B. The changes of FVmca using trans－cranial Doppler and moisture in brain tissues were observed. Results The normal value of FVmca was (31.8± 4.5)cm/s, while the value of FVmca in group A and B were (15.4± 3.9)cm/s and (22.1± 3.5)cm/s separately.Water content in damaged hemisphere in Group A and B were (81.54± 0.55)％ and (79.35± 0.50)％ respectively. There was a significant difference between the 2 groups (P<0.05). The levels of FVmca in group A and B were lower than that of control and there was also a significant difference between group A and B (P<0.05).Conclusions FVmca decreased and the brain moisture increased after brain injury while FVmca increased and the brain moisture reduced after treatment with dexamethasone. It demonstreated that local treatment of dexamethasone had an obvious therapeutical effect on brain injury.
基金the grants from Jilin Science and Technology Bureau,No.20030422-02
文摘BACKGROUND: With the development of interventional therapy, it is necessary for evaluating cerebral vessels to instruct treatment and determine prognosis of patients with ischemic stroke; however, correlation of distribution of infarction focus and clinical symptoms with degrees of cerebrovascular stricture is still unclear. OBJECTIVE: To evaluate the characteristics of cerebral arterial stricture of patients with ischemic stroke with transcranial Doppler (TCD) and color duplex flow imaging (CDFI) and compare the correlation between distribution of cerebral infarction focus and clinical types with magnetic resonance imaging (MRI). DESIGN: Contrast observation. SETTING: Department of Neurology, the First Hospital of Jilin University. PARTICIPANTS: A total of 159 patients with ischemic stroke were selected from the Department of Neurology, the First Hospital of Jilin University from January to December 2005, including 106 males and 53 females aged from 27 to 88 years. Bases on diagnostic criteria of cerebrovascular disease established by Rao et al, clinical manifestations of all patients were evaluated with CT or nuclear magnetic resonance. All patients provided the confirmed consent. METHODS: The accepted patients received TCD and CDFI examination at 1 week after onset of ischemic stroke. Among them, 112 patients received cerebrovascular imaging examination simultaneously. MRI was used to check cerebral infarction focus and cerebrovascular stricture > 50% was regarded as the accepted vessels. In addition, DWI-T2 TCD (Germany) was used to check middle cerebral artery, and degrees of middle cerebral artery were classified into mild, moderate and severe stricture based on blood velocity (140 cm/s, 180 cm/s). Stroke was classified based on characteristics of infarction focus and clinical symptoms showed with MRI and correlation with degrees of cerebrovascular stricture was analyzed simultaneously. MAIN OUTCOME MEASURES: Correlation between the characteristics of ischemic stroke and clinical symptoms checked with TCD and CDFI. RESULTS: A total of 159 patients with ischemic stroke were involved in the final analysis; in addition, 112 cases received cerebrovascular imaging examination simultaneously. ① MRI results of 159 patients with cerebral artery occlusive disease (CAOD): There were 131 patients (82.3%) with cerebral infarction, 40 (25.2%) with transient ischemic attack and 4 (2.5%) with subclavian steal syndrome (SSS). ② Infarction types with MRI examination: There were 33 patients (20.8%) with solitary cerebral infarction and 98 (61.6%) with multiple-cerebral infarction. ③ Results of TCD, CDFI, MRI angiography, CT angiography and digital subtraction angiography (DSA): Among 112 patients, 181 lesion sites (61.8%) were located in cranium and 112 lesion sites were located out of cranium; especially, lesion site was mostly observed in stem of middle cerebral artery (31.2%) and watershed of basilar artery (7.2%) in cranium and the beginning site of internal carotid artery (21.4%) out of cranium. ④ Correlation of vascular stricture checking with TCD, MRI and clinical diagnosis: On one hand, MRI and clinical diagnosis demonstrated that 68 patients had a watershed infarction; meanwhile, TCD examination indicated that there were 3 patients with mild vascular stricture, 24 with moderate vascular stricture and 36 with severe vascular stricture. On the other hand, among 68 patients with non-watershed infarction, there were 27 patient with mild vascular stricture, 26 with moderate vascular stricture and 15 with severe vascular stricture. There were significant differences (χ2 =26.854, P =0.001). Clinical diagnosis indicated that 40 patients had transient ischemic attack and TCD examination demonstrated that there were 8 patient with mild vascular stricture, 12 with moderate vascular stricture and 20 with severe vascular stricture. There were significant differences as compared with 68 patients with watershed infarction (χ2 =21.258, P =0.001). ⑤ Correlation of vascular stricture checking with CDFI, MRI and clinical diagnosis: On one hand, among patients who were determined as watershed infarction with MRI and clinical diagnosis, CDFI examination indicated that there were 32 patients with mild vascular stricture at neck, 25 with moderate vascular stricture and 6 with severe vascular stricture. On the other hand, among patients with non-watershed infarction, there were 48 patient with mild vascular stricture, 18 with moderate vascular stricture and 2 with severe vascular stricture. There were significant differences (χ2 =6.018, P =0.019). Among patients with transient ischemic attack checking with clinical diagnosis, there were 23 patient with mild vascular stricture, 9 with moderate vascular stricture and 8 with severe vascular stricture. There were no significant differences as compared with patients with non-watershed infarction (χ2 =0.597, P =0.440). CONCLUSION: ① TCD and CDFI are effective marks to determine cerebral arterial stricture and hemodynamical changes. ② Infarction and transient ischemic attack at watershed are generally clinical phenotypes of CAOD patients and infarction at watershed is correlated with degrees of cerebrovascular stricture. ③ TCD, MRI and clinical analysis of stroke types are significant for instructing treatment and evaluate prognosis.
文摘Objective: To evaluate the assessment of intracranial hypertension and nerve injury in patients with hypertensive cerebral hemorrhage by transcranial Doppler (TCD). Methods: The patients who were hospitalized for hypertensive cerebral hemorrhage between August 2014 and February 2017 were selected as the cerebral hemorrhage group and healthy subjects who received physical examination during the same period were selected as the control group;TCD was used to determine the PI of affected-side and unaffected-side middle cerebral artery in cerebral hemorrhage group and lumbar puncture was done to measure intracranial pressure. The serum was collected from the two groups to detect the levels of inflammatory cytokines and nerve injury markers. Results: PI level in affected-side middle cerebral artery of cerebral hemorrhage group was significantly higher than that in the unaffected-side and positively correlated with intracranial pressure level;serum IL-1β, TNF-α, ICAM-1, MMP9, YKL-40, Asp, Glu, NPY, NSE and GFAP levels of cerebral hemorrhage group were significantly higher than those of control group, and serum IL-1β, TNF-α, ICAM-1, MMP9, YKL-40, Asp, Glu, NPY, NSE and GFAP levels of cerebral hemorrhage group of patients with high PI level were significantly higher than those of cerebral hemorrhage group of patients with low PI level. Conclusion: TCD parameters can evaluate the degree of intracranial pressure increase and nerve injury in patients with hypertensive cerebral hemorrhage.
文摘[SUMMARY] TTTT is a non-invasive and new investigative examination,and a most important method of clinical diagnosis for many diseases,specially for orthostatic syncope,autonomic failure,intracranial hypertension,neurodegenerative diseases,CVAs and so on.At the same time,TCD technique for non-invasive monitoring of CBFV has also provided a new tool for investigating CA.In clinical circumstance,we may carry on assessment of dynamic CA by TTTT,and this kind of method has been proved to be appropriate to examine patients and monitor.we can choose different tilt positions by tilt-table according to the different demands for clinical diagnosis or researches,and record the different appearances of various index signs,we can take advantage of the technique of transfer function analysis of power spectrum between spontaneous changes in CBF and other factors(such as arterial pressure) to do research on the specific mechanism of impaired CA.
