scholarly journals Vascular Graph Model to Simulate the Cerebral Blood Flow in Realistic Vascular Networks

2009 ◽  
Vol 29 (8) ◽  
pp. 1429-1443 ◽  
Author(s):  
Johannes Reichold ◽  
Marco Stampanoni ◽  
Anna Lena Keller ◽  
Alfred Buck ◽  
Patrick Jenny ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Three Dimensional ◽  
Graph Model ◽  
Detailed Knowledge ◽  
Pressure Gradients ◽  
Vascular Networks ◽  
Modeling Framework ◽  
Cross Sectional ◽  
Capillary Bed

At its most fundamental level, cerebral blood flow (CBF) may be modeled as fluid flow driven through a network of resistors by pressure gradients. The composition of the blood as well as the cross-sectional area and length of a vessel are the major determinants of its resistance to flow. Here, we introduce a vascular graph modeling framework based on these principles that can compute blood pressure, flow and scalar transport in realistic vascular networks. By embedding the network in a computational grid representative of brain tissue, the interaction between the two compartments can be captured in a truly three-dimensional manner and may be applied, among others, to simulate oxygen extraction from the vessels. Moreover, we have devised an upscaling algorithm that significantly reduces the computational expense and eliminates the need for detailed knowledge on the topology of the capillary bed. The vascular graph framework has been applied to investigate the effect of local vascular dilation and occlusion on the flow in the surrounding network.

scholarly journals Cerebral blood flow MRI in the nondemented elderly is not predictive of post-operative delirium but is correlated with cognitive performance

2016 ◽  
Vol 37 (4) ◽  
pp. 1386-1397 ◽  
Author(s):  
Tammy T Hshieh ◽  
Weiying Dai ◽  
Michele Cavallari ◽  
Charles RG Guttmann ◽  
Dominik S Meier ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cognitive Performance ◽  
Parietal Lobe ◽  
Elective Surgery ◽  
Verbal Learning ◽  
Three Dimensional ◽  
Performance Measure ◽  
Cross Sectional ◽  
Age Related

Three-dimensional Arterial Spin Labeling (ASL) MRI was performed before surgery in a cohort of 146 prospectively enrolled subjects ≥ 70 years old scheduled to undergo elective surgery. We investigated the prospective association between ASL-derived measures of cerebral blood flow (CBF) before surgery with postoperative delirium incidence and severity using whole-brain and globally normalized voxel-wise analysis. We also investigated the cross-sectional association of CBF with patients’ baseline performance on specific neuropsychological tests, and with a composite general cognitive performance measure (GCP). Out of 146 subjects, 32 (22%) developed delirium. We found no significant association between global and voxel-wise CBF with delirium incidence or severity. We found the most significant positive associations between CBF of the posterior cingulate and precuneus and the Hopkins Verbal Learning Test – Revised total score, Visual Search and Attention Test (VSAT) score and the GCP composite. VSAT score was also strongly associated with right parietal lobe CBF. ASL can be employed in a large, well-characterized older cohort to examine associations between CBF and age-related cognitive performance. Although ASL CBF measures in regions previously associated with preclinical Alzheimer’s Disease were correlated with cognition, they were not found to be indicators of baseline pathology that may increase risk for delirium.

Serial measurement of regional cerebral blood flow in patients with SAH using 133Xe inhalation and emission computerized tomography

1984 ◽  
Vol 60 (5) ◽  
pp. 916-922 ◽  
Author(s):  
Bruce Mickey ◽  
Sissel Vorstrup ◽  
Bo Voldby ◽  
Helle Lindewald ◽  
Aage Harmsen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Computerized Tomography ◽  
Cerebral Arteries ◽  
Three Dimensional ◽  
Neurological Deficits ◽  
Content Type ◽  
Serial Measurement ◽  
Regional Flow ◽  
Delayed Neurological Deterioration

✓ A noninvasive three-dimensional method for measuring cerebral blood flow (CBF), xenon-133 inhalation and emission computerized tomography, was used to investigate the CBF changes accompanying delayed neurological deterioration following subarachnoid hemorrhage (SAH). A total of 67 measurements were performed on 20 patients in Hunt and Hess' clinical Grades I to III in the first 21 days post SAH. Five patients with normal CBF tomograms on admission developed delayed neurological deficits in the 2nd week after hemorrhage, at which time repeat CBF tomograms in four patients revealed large areas of well defined regional flow decrease in the vascular territories of the anterior or middle cerebral arteries. Severe vasospasm was noted in three of these patients in whom arteriography was performed in the 2nd week post SAH. Diffuse bihemispheric CBF decreases were noted later in the course of delayed neurological deficits; however, measurements obtained soon after the onset of focal symptoms suggest that the only CBF decreases directly produced by vasospasm in Grade III patients are regional changes.

scholarly journals Cerebral Blood Flow Heterogeneity in Preterm Sheep: Lack of Physiologic Support for Vascular Boundary Zones in Fetal Cerebral White Matter

2007 ◽  
Vol 28 (5) ◽  
pp. 995-1008 ◽  
Author(s):  
Melissa M McClure ◽  
Art Riddle ◽  
Mario Manese ◽  
Ning Ling Luo ◽  
Dawn A Rorvik ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Ischemia Reperfusion ◽  
Three Dimensional ◽  
Cerebral White Matter ◽  
Periventricular White Matter ◽  
Fetal Sheep ◽  
Border Zones ◽  
Neurologic Disability

Periventricular white matter (PVWM) injury is the leading cause of neurologic disability in survivors of prematurity. To address the role of ischemia in PVWM and cerebral cortical injury, we hypothesized that immaturity of spatially distal vascular ‘end zones’ or ‘border zones’ predisposes PVWM to greater decreases in cerebral blood flow (CBF) than more proximal structures. We quantified regional CBF with fluorescently labeled microspheres in 0.65 gestation fetal sheep in histopathologically defined three-dimensional regions by post hoc digital dissection and coregistration algorithms. Basal flow in PVWM was significantly lower than in gyral white matter and cortex, but was equivalent in superficial, middle, and deep PVWM. Absolute and relative CBF (expressed as percentage of basal) did not differ significantly during ischemia or reperfusion between PVWM, gyral white matter, or cortex. Moreover, CBF during ischemia-reperfusion was equivalent in three adjacent PVWM levels and was not consistent with the magnitude of severity of PVWM injury, defined by TUNEL (terminal deoxynucleotidyltransferase-mediated dUPT nick end labeling) staining. However, the magnitude of ischemia was predicted by the severity of discrete cortical lesions. Hence, unlike cerebral cortex, unique CBF disturbances did not account for the distribution of PVWM injury. Previously defined cellular maturational factors, thus, appear to have a greater influence on PVWM vulnerability to ischemic injury than the presence of immature vascular boundary zones.

Verification of a Finite Element Method for Solving One-Dimensional Equations of Blood Flow Incorporating a Viscoelastic Wall Model

2009 ◽  
Author(s):  
Rashmi Raghu ◽  
Charles A. Taylor
Keyword(s):  
Blood Flow ◽  
Surgical Planning ◽  
Computational Cost ◽  
Three Dimensional ◽  
Momentum Equation ◽  
Cross Sectional ◽  
One Dimensional ◽  
The One ◽  
Modeling Flow ◽  
Three Dimensional Simulations

The one-dimensional (1-D) equations of blood flow consist of the conservation of mass equation, balance of momentum equation and a wall constitutive equation with arterial flow rate, cross-sectional area and pressure as the variables. 1-D models of blood flow enable the solution of large networks of blood vessels including wall deformability. Their level of detail is appropriate for applications such as modeling flow and pressure waves in surgical planning and their computational cost is low compared to three-dimensional simulations.

scholarly journals Baseline vs. cross-sectional MRI of concussion: distinct brain patterns in white matter and cerebral blood flow

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nathan W. Churchill ◽  
Michael G. Hutchison ◽  
Simon J. Graham ◽  
Tom A. Schweizer
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Cross Sectional

scholarly journals Differential contribution of cyclooxygenase to basal cerebral blood flow and hypoxic cerebral vasodilation

2020 ◽  
Vol 318 (2) ◽  
pp. R468-R479 ◽  
Author(s):  
J. Mikhail Kellawan ◽  
Garrett L. Peltonen ◽  
John W. Harrell ◽  
Alejandro Roldan-Alzate ◽  
Oliver Wieben ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Arteries ◽  
Relative Increase ◽  
Cross Sectional ◽  
Arterial Blood ◽  
Intracranial Arteries ◽  
Fraction Of Inspired Oxygen ◽  
Cerebral Vasodilation ◽  
Relative Change

Cyclooxygenase (COX) is proposed to regulate cerebral blood flow (CBF); however, accurate regional contributions of COX are relatively unknown at baseline and particularly during hypoxia. We hypothesized that COX contributes to both basal and hypoxic cerebral vasodilation, but COX-mediated vasodilation is greater in the posterior versus anterior cerebral circulation. CBF was measured in 9 healthy adults (28 ± 4 yr) during normoxia and isocapnic hypoxia (fraction of inspired oxygen = 0.11), with COX inhibition (oral indomethacin, 100mg) or placebo. Four-dimensional flow magnetic resonance imaging measured cross-sectional area (CSA) and blood velocity to quantify CBF in 11 cerebral arteries. Cerebrovascular conductance (CVC) was calculated (CVC = CBF × 100/mean arterial blood pressure) and hypoxic reactivity was expressed as absolute and relative change in CVC [ΔCVC/Δ pulse oximetry oxygen saturation ([Formula: see text])]. At normoxic baseline, indomethacin reduced CVC by 44 ± 5% ( P < 0.001) and artery CSA ( P < 0.001), which was similar across arteries. Hypoxia ([Formula: see text] 80%–83%) increased CVC ( P < 0.01), reflected as a similar relative increase in reactivity (% ΔCVC/−Δ[Formula: see text]) across arteries ( P < 0.05), in part because of increases in CSA ( P < 0.05). Indomethacin did not alter ΔCVC or ΔCVC/Δ[Formula: see text] to hypoxia. These findings indicate that 1) COX contributes, in a largely uniform fashion, to cerebrovascular tone during normoxia and 2) COX is not obligatory for hypoxic vasodilation in any regions supplied by large extracranial or intracranial arteries.

scholarly journals Changes in Cerebral Blood Flow during Cerebrospinal Fluid Pressure Manipulation in Patients with Normal Pressure Hydrocephalus: A Methodological Study

2004 ◽  
Vol 24 (5) ◽  
pp. 579-587 ◽  
Author(s):  
Brian K. Owler ◽  
Alonso Pena ◽  
Shahan Momjian ◽  
Zofia Czosnyka ◽  
Marek Czosnyka ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Normal Pressure Hydrocephalus ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Normal Pressure ◽  
Element Analysis ◽  
Csf Pressure ◽  
Arterial Blood ◽  
Positron Emission

The combination of cerebral blood flow measurement using 15O-water positron emission tomography with magnetic resonance coregistration and CSF infusion studies was used to study the global and regional changes in CBF with changes in CSF pressure in 15 patients with normal pressure hydrocephalus. With increases in CSF pressure, there was a variable increase in arterial blood pressure between individuals and global CBF was reduced, including in the cerebellum. Regionally, mean CBF decreased in the thalamus and basal ganglia, as well as in white matter regions. These reductions in CBF were significantly correlated with changes in the CSF pressure and with proximity to the ventricles. A three-dimensional finite-element analysis was used to analyze the effects on ventricular size and the distribution of stress during infusion. To study regional cerebral autoregulation in patients with possible normal pressure hydrocephalus, a sensitive CBF technique is required that provides absolute, not relative normalized, values for regional CBF and an adequate change in cerebral perfusion pressure must be provoked.

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