Changes In Cerebral Blood Vessels Research Articles

Age‐ and Sex‐Related Morphological Changes in Cerebral Blood Vessels: a 7T TOF MRA Study

AbstractBackgroundIn this study we evaluated age‐ and sex‐associated morphological changes of cerebral blood vessels using 7T Time‐of‐flight (TOF) magnetic resonance angiography (MRA).MethodOur study consisted of 25 cognitively normal older adults (20 female, mean age 68.2 years). Whole‐Brain TOF MRA images were collected on a 7T Siemens scanner at the University of Pittsburgh (slice number = 354, voxel size = 0.38*0.38*0.38 mm, 12 mins). An iterative vessel segmentation algorithm, VesselMapper, was used to segment blood vessels on TOF MRA images (Li et al., 2023). For each subject, vessels are further divided into large and small vessels by median split based on vessel diameters. Mean tortuosity of large vessels, small vessels and overall vessels was computed. Linear regression analyses were performed to evaluate the main effects of age and sex, and the age*sex interaction on vessel tortuosity and diameter.ResultAs shown in Figure 1, we found age‐related increase in mean vessel tortuosity (greater age is associated with greater tortuosity, p<0.02). This age‐related difference is driven by small vessels (p = 0.002) rather than large vessels (p = 0.7). We also found that age is positively associated with mean voxel tortuosity (p<0.001, black line in Figure 2). Furthermore, women showed greater age‐related increase in mean arterial tortuosity, compared to men (age*sex interaction p = 0.04, Figure 2).ConclusionOur findings validated that morphological markers of cerebral blood vessels are sensitive to aging. Small vessels in the brain are particularly vulnerable. Further, compared to men, older women are at a higher risk for cerebral small vessel disease, which may contribute to elevated SVD‐related AD risk in women.Limitation: The study has an unbalanced sample (more women than men) and a relatively modest sample size (N = 25). A cross‐sectional instead of longitudinal design was used in this analysis. Future study with a large balanced sample and a longitudinal design are required to confirm our findings.Reference: Li, Jiatai, et al. “VesselMapper ‐ A Robust Vessel Segmentation Algorithm for 3D Images.” Annual Meeting of the Organization for Human Brain Mapping. 2023

Age‐ and Sex‐Related Morphological Changes in Cerebral Blood Vessels: a 7T TOF MRA Study

AbstractBackgroundIn this study we evaluated age‐ and sex‐associated morphological changes of cerebral blood vessels using 7T Time‐of‐flight (TOF) magnetic resonance angiography (MRA).MethodOur study consisted of 25 cognitively normal older adults (20 female, mean age 68.2 years). Whole‐Brain TOF MRA images were collected on a 7T Siemens scanner at the University of Pittsburgh (slice number = 354, voxel size = 0.38*0.38*0.38 mm, 12 mins). An iterative vessel segmentation algorithm, VesselMapper, was used to segment blood vessels on TOF MRA images (Li et al., 2023). For each subject, vessels are further divided into large and small vessels by median split based on vessel diameters. Mean tortuosity of large vessels, small vessels and overall vessels was computed. Linear regression analyses were performed to evaluate the main effects of age and sex, and the age*sex interaction on vessel tortuosity and diameter.ResultAs shown in Figure 1, we found age‐related increase in mean vessel tortuosity (greater age is associated with greater tortuosity, p<0.02). This age‐related difference is driven by small vessels (p = 0.002) rather than large vessels (p = 0.7). We also found that age is positively associated with mean voxel tortuosity (p<0.001, black line in Figure 2). Furthermore, women showed greater age‐related increase in mean arterial tortuosity, compared to men (age*sex interaction p = 0.04, Figure 2).ConclusionOur findings validated that morphological markers of cerebral blood vessels are sensitive to aging. Small vessels in the brain are particularly vulnerable. Further, compared to men, older women are at a higher risk for cerebral small vessel disease, which may contribute to elevated SVD‐related AD risk in women. Limitation: The study has an unbalanced sample (more women than men) and a relatively modest sample size (N = 25). A cross‐sectional instead of longitudinal design was used in this analysis. Future study with a large balanced sample and a longitudinal design are required to confirm our findings. Reference: Li, Jiatai, et al. “VesselMapper ‐ A Robust Vessel Segmentation Algorithm for 3D Images.” Annual Meeting of the Organization for Human Brain Mapping. 2023

Transcranial Doppler Ultrasonography detection on cerebrovascular flow for evaluating neonatal hypoxic-ischemic encephalopathy modeling.

This study aimed to investigate the feasibility of Transcranial Doppler Ultrasonography (TCD) in evaluating neonatal hypoxic-ischemic encephalopathy (NHIE) modeling through monitoring the alteration of cerebrovascular flow in neonatal hypoxic-ischemic (HI) rats. Postnatal 7-day-old Sprague Dawley (SD) rats were divided into the control group, HI group, and hypoxia (H) group. TCD was applied to assess the changes of cerebral blood vessels, cerebrovascular flow velocity, and heart rate (HR) in sagittal and coronal sections at 1, 2, 3, and 7 days after the operation. For accuracy, cerebral infarct of rats was examined by 2,3,5-Triphenyl tetrazolium chloride (TTC) staining and Nissl staining to simultaneously verify the establishment of NHIE modeling. Coronal and sagittal TCD scans revealed obvious alteration of cerebrovascular flow in main cerebral vessels. Obvious cerebrovascular back-flow was observed in anterior cerebral artery (ACA), basilar artery (BA), middle cerebral artery (MCA) of HI rats, along with accelerated cerebrovascular flows in the left internal carotid artery (ICA-L) and BA, decreased flows in right internal carotid artery (ICA-R) relative to those in the H and control groups. The alterations of cerebral blood flows in neonatal HI rats indicated successful ligation of right common carotid artery. Besides, TTC staining further validated the cerebral infarct was indeed caused due to ligation-induced insufficient blood supply. Damage to nervous tissues was also revealed by Nissl staining. Cerebral blood flow assessment by TCD in neonatal HI rats contributed to cerebrovascular abnormalities observed in a real-time and non-invasive way. The present study elicits the potentials to utilize TCD as an effective means for monitoring the progression of injury as well as NHIE modeling. The abnormal appearance of cerebral blood flow is also beneficial to the early warning and effective detection in clinical practice.

Biomechanical model of cerebral vascular dynamics and their effect on CSF dynamics

With advancing age venous wall thickness increases going along with a loss of elastic properties, the arterioles curl and capillary density decreases leading to a reduction of cross sectional area [1]. Even in healthy individuals these changes influence vascular and CSF dynamics, as a reduction of total cerebral blood flow, aqueduct and cervical stroke volume are reported [2]. In NPH these dynamics seem to be altered in a different way, as aqueduct stroke volume [2] and ICP amplitude are increased and arteriovenous delay is drastically reduced compared to normal aging [3]. However it is not clear in what way the described vascular alterations influence the pressure propagation inside the vessels and impact CSF dynamics. So far no biomechanical model exists that investigates the influence of macroscopic and microscopic changes of cerebral blood vessels. That is why we put a model up for discussion that simulates vascular pressure propagation and enables the investigation of altered vascular properties in the context of NPH. A Matlab Simulink model was developed reproducing each vessel section by a distensible compartment. Therefore the cerebral vascular tree was divided into 13 sections from carotid artery to venous sinuses and the pulsatile carotid artery and sinus pressure were inputted as Fourier series. The cross sectional area was varied according to literature data and flow resistance was implemented taking into account the rheological characteristics of blood. The Windkessel function and relaxation properties of vascular walls were integrated by a Voigt model, enabling the variation of wall properties for each section individually. Due to the distensible vessel walls each section interacts with the CSF compartment and autoregulation was implemented by a simple proportional controller. After parameterisation mean pressure and pressure amplitude in the vessel sections showed good accordance with literature values [4]. We have proposed a model of vascular dynamics that is able to identify the impact of altered vascular wall properties and structural changes. Furthermore the effect of different arterial and venous input pressure profiles can be analysed. These parameter analyses are part of our ongoing research.

Cerebral amyloid angiopathy: emerging concepts.

Cerebral amyloid angiopathy (CAA) involves cerebrovascular amyloid deposition and is classified into several types according to the amyloid protein involved. Of these, sporadic amyloid β-protein (Aβ)-type CAA is most commonly found in older individuals and in patients with Alzheimer's disease (AD). Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies). CAA-associated vasculopathies lead to development of hemorrhagic lesions [lobar intracerebral macrohemorrhage, cortical microhemorrhage, and cortical superficial siderosis (cSS)/focal convexity subarachnoid hemorrhage (SAH)], ischemic lesions (cortical infarction and ischemic changes of the white matter), and encephalopathies that include subacute leukoencephalopathy caused by CAA-associated inflammation/angiitis. Thus, CAA is related to dementia, stroke, and encephalopathies. Recent advances in diagnostic procedures, particularly neuroimaging, have enabled us to establish a clinical diagnosis of CAA without brain biopsies. Sensitive magnetic resonance imaging (MRI) methods, such as gradient-echo T2* imaging and susceptibility-weighted imaging, are useful for detecting cortical microhemorrhages and cSS. Amyloid imaging with amyloid-binding positron emission tomography (PET) ligands, such as Pittsburgh Compound B, can detect CAA, although they cannot discriminate vascular from parenchymal amyloid deposits. In addition, cerebrospinal fluid markers may be useful, including levels of Aβ40 for CAA and anti-Aβ antibody for CAA-related inflammation. Moreover, cSS is closely associated with transient focal neurological episodes (TFNE). CAA-related inflammation/angiitis shares pathophysiology with amyloid-related imaging abnormalities (ARIA) induced by Aβ immunotherapies in AD patients. This article reviews CAA and CAA-related disorders with respect to their epidemiology, pathology, pathophysiology, clinical features, biomarkers, diagnosis, treatment, risk factors, and future perspectives.

Dynamic Cerebral Autoregulation Is Heterogeneous in Different Subtypes of Acute Ischemic Stroke

Background and PurposeStroke of large-artery atherosclerosis and small-artery occlusion are two main subtypes of stroke according to TOAST classification. The underlying mechanisms of how these two subtypes affect dynamic cerebral autoregulation (dCA) might be heterogeneous, resulting in varied clinical conditions and outcomes. We therefore studied the pattern of dCA in these two subtypes.MethodsForty-one patients with acute unilateral middle cerebral artery (MCA) territory stroke (15 with ipsilateral large-artery atherosclerosis and 26 with small-artery occlusion) and 20 healthy volunteers were enrolled. Non-invasive continuous cerebral blood flow velocity and arterial blood pressure were recorded simultaneously from each subject in supine position using transcranial Doppler on MCA bilaterally and servo-controlled plethysmograph on the middle finger, respectively. Transfer function analysis was applied to derive autoregulatory parameters, gain, phase difference (PD), and slope of step response.ResultsIn the large-artery atherosclerosis group, PD in affected hemisphere was 42.9±18.5 degree, which is significantly lower than the unaffected hemisphere (72.4±29.9 degree, P<0.01), and the healthy group (P<0.01). However, PD is similar in the unaffected hemisphere and healthy group (P>0.1). In the small-artery occlusion group, PD in the affected hemisphere was similar to that in the contralateral hemisphere (33.8±17.9 vs. 32.6±21.1 degree, P>0.1), both sides were significantly lower than the healthy group (all P<0.001).The results of the slope of step response agree with the findings in PD.ConclusionsDCA in different subtypes of acute ischemic stroke is heterogeneous, which might be attributed to the varied pathologic changes of cerebral blood vessels.

MDCTA diagnosis of cerebral vessel disease among patients with arterial hypertension.

SummaryBackground:to study changes involving cerebral vessels in patients with hypertension and various levels of total cardiovascular risk.Material/Methods:One hundred and thirty-four patients underwent CT-angiography of intracranial vessels. Ninety-eight of them were diagnosed with hypertension. Taking into consideration high blood pressure, presence of risk factors and target organ damage subjects were divided into 4 groups: with low, medium, high and very high total cardiovascular risk. Control group included 36 patients. They were not diagnosed with hypertension at the time of examination. One hundred and five patients were examined using a 4-slice CT scanner (Toshiba Asteion 4, Toshiba Medical System, Japan), and 29 patients were examined using a 128-slice scanner (Siemens Definition AS+, Siemens Healthcare, Germany) with an injection system. We used iodine-containing contrast agents such as iodixanol and iopromide for angiography.Results:Anatomical and topographic changes of cerebral vessels were most frequently found in hypertensive patients with high and very high total cardiovascular risk. Narrowing of vertebral vessels was the most common change (27 patients (27.55%), 21 patients (21.43%) had narrowing of the right artery, and 6 (6.12%) subjects – of the left one). Tortuous course of internal carotid arteries at the neck level was visualized in 11 patients (11.22%). Narrowing of A1 segment of anterior cerebral artery was noted in 9 patients (9.18%), of the right one – in 8 patients (8.16%), of the left one – in 1 patient (1.02%). Aneurysmal dilation of intracranial vessels was visualized in 6 patients (6.12%). Saccular aneurysm of left internal carotid artery was diagnosed in 2 patients (2.04%), one patient (1.02%) had right internal carotid artery aneurysm and one patient (1.02%) had an aneurysm of the basilar artery.Discussions:the most common changes of cerebral vessels diagnosed in MDCTA among patients with hypertension included various degrees of narrowing of vertebral vessels, anterior, posterior and posterior communicating arteries and internal carotid arteries. Changes of middle cerebral arteries and basilar arteries were extremely rare, thus we can say that these vessels are influenced by high blood pressure to lesser extent. We established the relationship between changes in cerebral blood vessels and total cardiovascular risk. Therefore, we believe that findings will be useful for establishing prognosis in hypertension and prevention of complications such as stroke.Conclusions:MDCT angiography is a highly informative method to study changes of cerebral vessels in patients with hypertension. The relationship between changes in cerebral blood vessels diagnosed through MDCT angiography and the level of total cardiovascular risk among patients with hypertension had been established.

第８脳神経に対する神経血管圧迫症候群について

Neurovascular compression syndrome (NVCS) involves neuropathy due to intracranial blood vessels compressing the cranial nerves. NVCS of the eighth cranial nerve is less reportedly established as a clinical entity than that of the fifth and seventh cranial nerves. We report 17 cases of NVCS of the eighth cranial nerve and their clinical features. Clinical symptoms and test findings among our subjects indicated that (1) most were aged more than 65 years, (2) were unilateral, (3) had intermittent tinnitus, (4) suffered attacks lasting a few seconds dozens of times a day, (5) experienced dizziness concomitantly with tinnitus, (6) aggrevated tinnitus and dizziness when tilting the head toward the affected side and looking downward (positional tinnitus, positional dizziness), (7) heard specific tinnitus sounds such as crackling differing from those in cochlear tinnitus, (8) had mild or no hearing loss, (9) were diagnosed with retrocochlear hearing disturbance due to an interpeak latency delay between waves I and III of the auditory brainstem response (ABR), (10) often had no nystagmus or canal paresis (CP), (11) were found in constructive interference steady state magnetic resonance imaging (CISS MRI) to have compression of the eighth cranial nerve by the vertebral artery (VA) or the anterior inferior cerebellar artery (AICA), (12) rarely had concomitant facial spasms, and (13) had tinnitus and dizziness markedly suppressed by carbamazepine. With the number of elderly individuals continuing to increase, cases of NVCS due to arteriosclerotic changes in cerebral blood vessels are expected to increase, making it necessary to consider NVCS in elderly subjects with dizziness, tinnitus, and hearing loss.

Cerebral vascular changes during chronic hypertension

To examine new concepts concerning structural changes in cerebral blood vessels during chronic hypertension, and to examine mechanisms that lead to cerebral vascular complications, in light of the hypothesis that hypertensive vascular hypertrophy may be harmful. Literature review. The evidence suggests that the current view is not correct in relation to the cerebral circulation. Vascular hypertrophy and remodeling appear to protect cerebral vessels during hypertension, instead of being harmful. Major cerebral vascular complications during hypertension may be largely due to endothelial dysfunction. One function of the cerebral endothelium is to serve as the blood-brain barrier. Disruption of the blood-brain barrier appears to mediate hypertensive encephalopathy. A second endothelial function is to modulate vascular tone. Abnormalities in vasoactive factors that are released by the endothelium (impaired vasodilator mechanisms and augmented vasoconstrictor mechanisms) may make an important contribution to the pathophysiology of transient ischemic episodes, and perhaps stroke, in chronic hypertension.

Adaptive changes in cerebral blood vessels during chronic hypertension reply

Adaptive changes in cerebral blood vessels during chronic hypertension reply

Ultrastructural changes in cerebral blood vessels of sheep injected with tunicamycin

Changes resembling those of annual ryegrass toxicity were produced in sheep by the subcutaneous injection of tunicamycin and the cerebellum was examined by electron microscopy. The results suggested vascular endothelial damage as the basis for the cerebral lesions in this condition.

ALTERNATING HEMIPLEGIA IN CHILDHOOD: A REPORT OF EIGHT PATIENTS WITH COMPLICATED MIGRAINE BEGINNING IN INFANCY

In this report eight patients are described who suffer an unusual symptom complex of intermittent, alternating hemiplegia. Symptoms have begun in early childhood and in one child at age 3 months. Typically, there is a brief vasomotor prodrome and then the abrupt onset of hemiplegia. Contralateral headache tends to develop soon after the onset of neurological symptoms. Recovery is usual within several hours but may be prolonged over several days. Recurrence during early childhood is frequent. Serial electroencephalograms have shown fluctuating and inconstant slow wave abnormalities as occur with cerebral ischaemia, but radiological investigations have failed to indicate structural or dynamic changes in cerebral blood vessels. The treatment of the disorder is symptomatic and antiserotonin compounds have not been found to be effective. As these children have matured, attacks have become less frequent and in some a more characteristic picture of migraine has emerged. In several patients residual neurological signs including dementia and dyskinesia are now present. Because convulsions occasionally occur with the hemiplegia, differentiation from a primary seizure disorder is often difficult. The profile and evolution of symptoms, however, suggests that these patients suffer a primary vascular disorder within the category of migraine, but they are unusual in the early onset of symptoms and the fixed neurological deficits that may ensue.

Role of noradrenaline and angiotension on cerebral circulation in juvenile essential hypertension

Cases of essential hypertension are predominant among the so-called hypertensive. However, its etiology still remains unclarified, since it is likely to be with various factors. Hemodynamically essential hypertension resembles conditions following injection of noradrenaline. Since the study of experimental hypertension caused by a stricture of the renal artery, a role played by the renin-angiotensin system has been considered to be of importance in developing essential hypertension. It is known, that cases of essential hypertension show an accelerated pressure response to catecholamines and angiotensin although there is no increase in either of these agents. It is of interest to find reports that hypertension was induced in dogs by a constriction of the internal carotid artery or ligation of the basilar artery, and that angiotensin enhanced pressor response following a constriction of cerebral blood vessels and it had central hypertensive effect. It is thus considered that cerebral circulation plays a very important role in the etiology of hypertension. The present study was carried out in solving that problem. Materials and Methods 1. Cerebral circulation in patients with juvenile essential hypertension Patients with juvenile essential hypertension below 34 years of age were studied in comparison with normotensive subjects about the same age. Older subjects were excluded, because their cerebral blood flow tends to decrease as their age advance and their cerebral vascular reactivity is affected by organic changes in cerebral blood vessels. The cerebral blood flow was measured by the nitrous oxide method of KETY and SCHMIDT, as modified by AIZAWA or SCHEINBERG and STEAD, blood gas analysis was made by the manometric technique of VAN SLYKE and NEILL, and measurements of blood pH and blood gas tension were made by means of an I.L. meter.