This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-con...This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.展开更多
Cerebral small vessel disease is a neurological disease that affects the brain microvasculature and which is commonly observed among the elderly.Although at first it was considered innocuous,small vessel disease is no...Cerebral small vessel disease is a neurological disease that affects the brain microvasculature and which is commonly observed among the elderly.Although at first it was considered innocuous,small vessel disease is nowadays regarded as one of the major vascular causes of dementia.Radiological signs of small vessel disease include small subcortical infarcts,white matter magnetic resonance imaging hyperintensities,lacunes,enlarged perivascular spaces,cerebral microbleeds,and brain atrophy;however,great heterogeneity in clinical symptoms is observed in small vessel disease patients.The pathophysiology of these lesions has been linked to multiple processes,such as hypoperfusion,defective cerebrovascular reactivity,and blood-brain barrier dysfunction.Notably,studies on small vessel disease suggest that blood-brain barrier dysfunction is among the earliest mechanisms in small vessel disease and might contribute to the development of the hallmarks of small vessel disease.Therefore,the purpose of this review is to provide a new foundation in the study of small vessel disease pathology.First,we discuss the main structural domains and functions of the blood-brain barrier.Secondly,we review the most recent evidence on blood-brain barrier dysfunction linked to small vessel disease.Finally,we conclude with a discussion on future perspectives and propose potential treatment targets and interventions.展开更多
Blood velocity in the vertebral artery and the basilar artery was observed before and after acupuncture at Fengchi point (GB 20) in 97 patients by transcranial Doppler ultrasonic detecting. The results showed that the...Blood velocity in the vertebral artery and the basilar artery was observed before and after acupuncture at Fengchi point (GB 20) in 97 patients by transcranial Doppler ultrasonic detecting. The results showed that the blood velocity in patients with either high or low blood flow had significant changes after acupuncture (P展开更多
Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many...Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many controversies. This study aimed to investigate hemodynamic changes in symptomatic leukoaraiosis using transcranial Doppler ultrasonography and the breath-holding test in a Chinese Han population, from northern China. A total of 203 patients who were diagnosed with ischemic stroke or clinical chronic progressive ischemic symptoms were enrolled in this study, including 97 males and 106 females, with an age range of 43-93 years. The severity of leukoaraiosis was evaluated according to the Fazekas grading scale, and patients were divided into four groups accordingly. Grade 0 was no leukoaraiosis, and grades I, II, and III were mild, moderate, and severe leukoaraiosis, respectively, with 44, 79, 44, and 36 cases in each group. Transcranial Doppler ultrasonography and the breath-holding test were performed. The mean blood flow velocity of the bilateral middle cerebral artery was measured and the breath-holding index was calculated. The breath holding index was correlated with leukoaraiosis severity and cognitive impairment. Patients with a low breath holding index presented poor performance in the Montreal Cognitive Assessment (MoCA) and executive function tests. That is, the lower the breath holding index, the lower the scores for the MoCA and the higher for the trail-making test Parts A and B. These results indicate that the breath-holding index is a useful parameter for the evaluation of cerebrovascular reserve impairment in patients with leukoaraiosis. In addition, the breath-holding index can reflect cognitive dysfunction, providing a new insight into the pathophysiology of leukoaraiosis. This study was approved by the Ethics Committee of the Fifth Peoples Hospital of Shenyang, China (approval No. 20160301) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800014421).展开更多
基金the Medical Program of the Scientific & Technical Foundation in Xiamen(MRI study of chronic cerebrovascular insufficiency) in 2008,No.3502Z20084028
文摘This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.
基金supported by China Scholarship Council(202208210093,to RJ)。
文摘Cerebral small vessel disease is a neurological disease that affects the brain microvasculature and which is commonly observed among the elderly.Although at first it was considered innocuous,small vessel disease is nowadays regarded as one of the major vascular causes of dementia.Radiological signs of small vessel disease include small subcortical infarcts,white matter magnetic resonance imaging hyperintensities,lacunes,enlarged perivascular spaces,cerebral microbleeds,and brain atrophy;however,great heterogeneity in clinical symptoms is observed in small vessel disease patients.The pathophysiology of these lesions has been linked to multiple processes,such as hypoperfusion,defective cerebrovascular reactivity,and blood-brain barrier dysfunction.Notably,studies on small vessel disease suggest that blood-brain barrier dysfunction is among the earliest mechanisms in small vessel disease and might contribute to the development of the hallmarks of small vessel disease.Therefore,the purpose of this review is to provide a new foundation in the study of small vessel disease pathology.First,we discuss the main structural domains and functions of the blood-brain barrier.Secondly,we review the most recent evidence on blood-brain barrier dysfunction linked to small vessel disease.Finally,we conclude with a discussion on future perspectives and propose potential treatment targets and interventions.
文摘Blood velocity in the vertebral artery and the basilar artery was observed before and after acupuncture at Fengchi point (GB 20) in 97 patients by transcranial Doppler ultrasonic detecting. The results showed that the blood velocity in patients with either high or low blood flow had significant changes after acupuncture (P
文摘Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many controversies. This study aimed to investigate hemodynamic changes in symptomatic leukoaraiosis using transcranial Doppler ultrasonography and the breath-holding test in a Chinese Han population, from northern China. A total of 203 patients who were diagnosed with ischemic stroke or clinical chronic progressive ischemic symptoms were enrolled in this study, including 97 males and 106 females, with an age range of 43-93 years. The severity of leukoaraiosis was evaluated according to the Fazekas grading scale, and patients were divided into four groups accordingly. Grade 0 was no leukoaraiosis, and grades I, II, and III were mild, moderate, and severe leukoaraiosis, respectively, with 44, 79, 44, and 36 cases in each group. Transcranial Doppler ultrasonography and the breath-holding test were performed. The mean blood flow velocity of the bilateral middle cerebral artery was measured and the breath-holding index was calculated. The breath holding index was correlated with leukoaraiosis severity and cognitive impairment. Patients with a low breath holding index presented poor performance in the Montreal Cognitive Assessment (MoCA) and executive function tests. That is, the lower the breath holding index, the lower the scores for the MoCA and the higher for the trail-making test Parts A and B. These results indicate that the breath-holding index is a useful parameter for the evaluation of cerebrovascular reserve impairment in patients with leukoaraiosis. In addition, the breath-holding index can reflect cognitive dysfunction, providing a new insight into the pathophysiology of leukoaraiosis. This study was approved by the Ethics Committee of the Fifth Peoples Hospital of Shenyang, China (approval No. 20160301) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800014421).
