Comparing use of an artery in the wrist to an artery in the groin to access the blood vessels leading to the brain for cerebral angiography (visualising blood flow in the brain)

2019 ◽  
Author(s):  
Kartik Bhatia ◽  
Vitor Mendes Pereira
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Cerebral Angiography ◽  
The Brain

119 Visualization of Vascular Structures of the Brain Through a Novel Multispectral Fluorescence Microscope After Intravenous Application of ICG

Neurosurgery ◽  
2017 ◽  
Vol 64 (CN_suppl_1) ◽  
pp. 226-226
Author(s):  
Dimitrios Athanasopoulos
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Intravenous Injection ◽  
White Light ◽  
Surgical Microscope ◽  
Light Image ◽  
Fluorescent Image ◽  
Surgical Clip ◽  
Vascular Structures ◽  
The Brain

Abstract INTRODUCTION Vascular structures are intraoperatively visualized through the eye-piece of a surgical microscope. The blood flow within the blood vessels can be demonstrated via indocyanine green (ICG) fluorescence. In this study we wanted to find out whether the development of a novel fluorescent surgical microscope, overlapping a multispectral fluorescent image on a white light image, is superior, equal or inferior, compared to the previous models. Moreover, it shall be proved, whether multispectral fluorescence enhances surgeon's orientation through the precise and clearer visualization of blood vessels and the blood flow. METHODS A total of 8 porcine animal models were used. After fixation of the animal's head the parietal cortex and the cortical blood vessels were exposed. A digital imaging of the arterial perfusion, capillary transition and venous drainage after intravenous injection of ICG (5 ml; 5 mg/ml) was then performed. The blood flow was artificially blocked by a surgical clip. After repetitive intravenous injection of ICG and visualisation with multispectral view, the surgical clip was removed and the reperfusion of the brain tissue was visualized with the real time ICG perfusion. RESULTS >The visualization of the anatomical structures of the surgical field under white light as well as the image overlapping were easily performed. The occlusion of blood vessels with surgical clips demonstrate a blockage of the ICG perfusion on the multispectral fluorescent image. The ICG perfusion was again demonstrated after removing the surgical clip and reperfusion of the blood vessel. CONCLUSION Multispectral fluorescence was shown to be superior to the classic ICG fluorescence. With the development of a novel multispectral surgical microscope, which overlaps a fluorescent image on a white light image, the data delivered to the surgeon are enhanced, compared to the previous models. Moreover, the surgeons's orientation is improved thanks to the clear visualization of blood vessels and the blood flow.

Effects of hematocrit variations on regional hemodynamics and oxygen transport in the dog

1980 ◽  
Vol 238 (4) ◽  
pp. H545-H522 ◽  
Author(s):  
F. C. Fan ◽  
R. Y. Chen ◽  
G. B. Schuessler ◽  
S. Chien
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Vessels ◽  
Oxygen Transport ◽  
Oxygen Supply ◽  
Blood Flows ◽  
Regional Hemodynamics ◽  
Regional Blood Flows ◽  
Splenic Vessels ◽  
The Brain

The responses of alterations in regional hemodynamics and oxygen transport rate to hematocrit (Hct) were studied in 20 pentobarbitalized dogs. Hemodilution was carried out by isovolemic exchange with plasma in 12 dogs and the hemoconcentration with packed cells in 8 dogs. The cardiac output and regional blood flows were determined with the microsphere technique. In hemodilution, the increases of blood flow to the myocardium and the brain were out of proportion to the increase of cardiac output; the oxygen supply to the myocardium remained unchanged while that to the brain decreased only slightly. In hemoconcentration, vasodilation occurred in the myocardium and the brain to maintain constant oxygen supply. Splenic vessels had marked vasoconstriction with Hct alteration in either direction. Blood vessels in the liver, intestine, and kidney responded with a milder vasoconstriction and maintained a constant oxygen supply between Hct of 30-55%. Therefore, during Hct alteration, redistribution of blood flow to myocardium and brain occurred. The optimal Hct range for constant oxygen supply was different among various organs.

The Neurovascular Unit: Focus on the Regulation of Arterial Smooth Muscle Cells

2020 ◽  
Vol 16 (5) ◽  
pp. 502-515 ◽  
Author(s):  
Patrícia Quelhas ◽  
Graça Baltazar ◽  
Elisa Cairrao
Keyword(s):  
Blood Flow ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Blood Vessels ◽  
Neurovascular Unit ◽  
Muscle Cells ◽  
Cerebral Blood Vessels ◽  
Mural Cells ◽  
Brain Pericytes ◽  
The Brain

The neurovascular unit is a physiological unit present in the brain, which is constituted by elements of the nervous system (neurons and astrocytes) and the vascular system (endothelial and mural cells). This unit is responsible for the homeostasis and regulation of cerebral blood flow. There are two major types of mural cells in the brain, pericytes and smooth muscle cells. At the arterial level, smooth muscle cells are the main components that wrap around the outside of cerebral blood vessels and the major contributors to basal tone maintenance, blood pressure and blood flow distribution. They present several mechanisms by which they regulate both vasodilation and vasoconstriction of cerebral blood vessels and their regulation becomes even more important in situations of injury or pathology. In this review, we discuss the main regulatory mechanisms of brain smooth muscle cells and their contributions to the correct brain homeostasis.

Edema, Fainting, and Strokes

2021 ◽  
pp. 216-240
Author(s):  
Graham Mitchell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Fluid Pressure ◽  
Basement Membranes ◽  
Tissue Pressure ◽  
Efficient Mechanisms ◽  
The Brain ◽  
Mediated Reduction

High blood pressure in humans is often associated with heart failure, edema, strokes, and episodes of fainting. Giraffes never show these. Edema, the abnormal collection of fluid in the lower legs, is prevented in giraffes by a combination of thick basement membranes of capillary blood vessels, which probably reduce their permeability to proteins, a very high tissue pressure that resists flow of fluid out of capillaries, and efficient mechanisms for returning blood to the heart. Fainting occurs when blood flow (and thus oxygen and glucose supply) to the brain is reduced. When a giraffe lifts its head after drinking water there is a sudden reduction of blood flow to the head, and fainting should result. Fainting is avoided because the blood flow that remains is diverted completely to the brain by a unique arrangement of blood vessels and nerves, and by structures that maintain the perfusion pressure of the blood flowing through the brain. Strokes can be caused by rupture of small blood vessels in the brain when they are exposed to high blood pressure of the kind reached in the head of a giraffe when it drinks surface water. Rupture of brain blood vessels is prevented in giraffes by mechanisms that reduce pressure. The posture adopted while drinking, baroreceptor-mediated reduction in cardiac output, the effects of the carotid rete, diversion of blood away from the brain, an increase in cerebrospinal fluid pressure, and passive and active constriction of blood vessels, all contribute.

scholarly journals Modeling of intracranial vessels and Simulation of cerebral blood flow

2020 ◽  
Vol 185 ◽  
pp. 03030
Author(s):  
Yingying Yan ◽  
Li Ke ◽  
Qiang Du ◽  
Xiaodi Ding ◽  
Jia Chen
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Vessels ◽  
Three Dimensional ◽  
Normal Operation ◽  
Automatic Regulation ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Anatomic Structure ◽  
The Brain

The stable regulation of cerebral blood flow plays an important role in the normal operation of brain function. The disturbance of cerebral blood flow automatic regulation will lead to brain injury and lead to cerebrovascular disease. Therefore, it is of practical clinical significance to study the fine modeling of intracranial blood vessels. First of all, based on the anatomic structure of the intracranial blood vessels, the above sagittal sinus vein, sigmoid sinus, superior petrosal sinus, transverse sinus and cerebral arterial circle were mainly modeled, the three-dimensional model of cerebral blood flow is constructed. Secondly, the three-dimensional model is given conductivity characteristics. Through the expansion and contraction of cerebral blood vessels to simulate the self-regulation of cerebral blood flow, the simulation method of cerebral blood flow impedance is studied. When the blood flow changes, the brain impedance is calculated. The simulation data shows that the change trend of the electric potential and the whole brain impedance of the outer layer of the brain is consistent with the theoretical analysis. The experimental results show that the impedance curves and changes calculated by the brain model in this study are consistent with the measured impedance results, which shows that the modeling method in this paper is precise and effective, and provides a theoretical basis for further study of cerebral blood flow problems.

Geometrical Models of Vertebral Arteries and Numerical Simulations of the Blood Flow Through Them

2008 ◽  
Author(s):  
Krzysztof Jozwik ◽  
Damian Obidowski
Keyword(s):  
Blood Flow ◽  
Numerical Simulations ◽  
Blood Vessels ◽  
Human Body ◽  
Special Kind ◽  
3D Models ◽  
Vertebral Arteries ◽  
The Individual ◽  
Physical Phenomena ◽  
The Brain

Vertebral arteries are a system of two blood vessels through which blood is carried to the rear region of the brain. This region of the human body has to be very well supplied with blood, without any breaks or deficiencies in the blood flow. Blood is delivered to the brain through carotid arteries as well. All these arteries are connected to the circle of Willis, which has to fulfill all demands of the human brain as far as the blood flow is concerned. However, vertebral arteries due to their position and shape are a special kind of blood vessels. They originate at various distances from the aortic ostium, may branch off at different angles, have various length, inner diameter and spatial shape. Three different geometries of vertebral arteries, which most frequently occur in the human body structure, have been chosen, and for each twenty five various combinations of artery inner diameters have been used to generate 3D models of these arteries. For seventy five different models thus created, the numerical simulations have been performed. The results obtained have indicated explicitly that differences in the flow and instantaneous velocity values in vertebral arteries and in the point they join to form the basilar artery do not result from pathological changes in the artery system, but may follow from physical phenomena that occur in arteries as a consequence of the pulsating character of the flow and the unique geometry, which is related to the individual human anatomical structure.

Blood circulation and fluid dynamics in the eye

1975 ◽  
Vol 55 (3) ◽  
pp. 383-417 ◽  
Author(s):  
A. Bill
Keyword(s):  
Endothelial Cells ◽  
Blood Flow ◽  
Blood Vessels ◽  
Sympathetic Nerves ◽  
Retinal Vessels ◽  
Nervous Stimulation ◽  
Permeability Characteristics ◽  
Ciliary Processes ◽  
Sympathetic Nervous ◽  
The Brain

The nutrition of the intraocular tissues is accomplished by the retinal vessels, the uveal vessels, and by the aqueous humor. Both morphologically and physiologically the retinal vessels are similar to those in the brain. The endothelial cells of the capillaries are attached to each other by tight junctions, the resistance vessels respond poorly to a large number of drugs, and the blood flow through the retina is autoregulated and very little affected by the sympathetic nervous system. The blood vessels of the iris also have morphological and permeability characteristics similar to those in the brain but they are under a strong influence from the sympathetic nerves and react to many drugs. The blood flow is autoregulated. The blood vessels of the choroid and the ciliary processes are similar to those in the small intestine and in the kidney. The endothelial cells of the capillaries are fenestrated; the vessels respond to sympathetic nervous stimulation and to a large number of vasoactive drugs. Autoregulation of the blood flow is intermediate in the ciliary body and very poor or absent in the choroid...

scholarly journals Intraoperative detection of blood vessels with an imaging needle during neurosurgery in humans

2018 ◽  
Vol 4 (12) ◽  
pp. eaav4992 ◽  
Author(s):  
Hari Ramakonar ◽  
Bryden C. Quirk ◽  
Rodney W. Kirk ◽  
Jiawen Li ◽  
Angela Jacques ◽  
...  
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Blood Vessels ◽  
Optical Coherence ◽  
Brain Hemorrhage ◽  
Biopsy Needle ◽  
Intraoperative Detection ◽  
Needle Probe ◽  
The Brain

Intracranial hemorrhage can be a devastating complication associated with needle biopsies of the brain. Hemorrhage can occur to vessels located adjacent to the biopsy needle as tissue is aspirated into the needle and removed. No intraoperative technology exists to reliably identify blood vessels that are at risk of damage. To address this problem, we developed an “imaging needle” that can visualize nearby blood vessels in real time. The imaging needle contains a miniaturized optical coherence tomography probe that allows differentiation of blood flow and tissue. In 11 patients, we were able to intraoperatively detect blood vessels (diameter, >500 μm) with a sensitivity of 91.2% and a specificity of 97.7%. This is the first reported use of an optical coherence tomography needle probe in human brain in vivo. These results suggest that imaging needles may serve as a valuable tool in a range of neurosurgical needle interventions.

Innervation of endoneurial microvessels in human sural nerve

1992 ◽  
Vol 50 (1) ◽  
pp. 920-921
Author(s):  
John L. Beggs ◽  
Peter C. Johnson ◽  
Astrid G. Olafsen ◽  
C. Jane Watkins
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Blood Supply ◽  
Peripheral Nerves ◽  
Sural Nerve ◽  
Nerve Fibers ◽  
Arterial Supply ◽  
Autonomic Nerve ◽  
Vasa Nervorum ◽  
Endoneurial Blood Flow

The blood supply (vasa nervorum) to peripheral nerves is composed of an interconnected dual circulation. The endoneurium of nerve fascicles is maintained by the intrinsic circulation which is composed of microvessels primarily of capillary caliber. Transperineurial arterioles link the intrinsic circulation with the extrinsic arterial supply located in the epineurium. Blood flow in the vasa nervorum is neurogenically influenced (1,2). Although a recent hypothesis proposes that endoneurial blood flow is controlled by the action of autonomic nerve fibers associated with epineurial arterioles (2), our recent studies (3) show that in addition to epineurial arterioles other segments of the vasa nervorum are also innervated. In this study, we examine blood vessels of the endoneurium for possible innervation.

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