Modelling solute transport in the brain microcirculation: is it really well mixed inside the blood vessels?

In this paper, we proposed a contrast-enhanced homemade spectral domain optical coherence tomography (SD-OCT) method for monitoring of brain microcirculation. We used the polyethylene glycol (PEG)-ylated gold nanorods (GNRs) as a contrast-enhanced agent, obtained clearly 2D and 3D OCT images of blood vessels and dynamic changes of probes in mouse blood vessels. Owing to high scattering of the PEG-GNRs, more tiny blood vessels can be imaged and the OCT signal can be enhanced by 5.87 dB after injection of PEG-GNRs for 20[Formula: see text]min, the enhancement then declined gradually for 60[Formula: see text]min. Our results demonstrate an effective technique for the enhanced imaging of blood vessels in vivo, especially for studies of the brain microcirculation, which could be serviced for disease mechanism research and therapeutic drug monitoring.

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Quantitative analysis of macroscopic solute transport in the murine brain

Fluids and Barriers of the CNS ◽

10.1186/s12987-021-00290-z ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Lori A. Ray ◽

Martin Pike ◽

Matthew Simon ◽

Jeffrey J. Iliff ◽

Jeffrey J. Heys

Keyword(s):

Experimental Data ◽

Solute Transport ◽

Blood Vessels ◽

Brain Tissue ◽

Molecular Transport ◽

Interstitial Space ◽

Perivascular Space ◽

Transport Parameter ◽

Dce Mri ◽

The Brain

Abstract Background Understanding molecular transport in the brain is critical to care and prevention of neurological disease and injury. A key question is whether transport occurs primarily by diffusion, or also by convection or dispersion. Dynamic contrast-enhanced (DCE-MRI) experiments have long reported solute transport in the brain that appears to be faster than diffusion alone, but this transport rate has not been quantified to a physically relevant value that can be compared to known diffusive rates of tracers. Methods In this work, DCE-MRI experimental data is analyzed using subject-specific finite-element models to quantify transport in different anatomical regions across the whole mouse brain. The set of regional effective diffusivities ($$D_{eff}$$ D eff ), a transport parameter combining all mechanisms of transport, that best represent the experimental data are determined and compared to apparent diffusivity ($$D_{app}$$ D app ), the known rate of diffusion through brain tissue, to draw conclusions about dominant transport mechanisms in each region. Results In the perivascular regions of major arteries, $$D_{eff}$$ D eff for gadoteridol (550 Da) was over 10,000 times greater than $$D_{app}$$ D app . In the brain tissue, constituting interstitial space and the perivascular space of smaller blood vessels, $$D_{eff}$$ D eff was 10–25 times greater than $$D_{app}$$ D app . Conclusions The analysis concludes that convection is present throughout the brain. Convection is dominant in the perivascular space of major surface and branching arteries (Pe > 1000) and significant to large molecules (> 1 kDa) in the combined interstitial space and perivascular space of smaller vessels (not resolved by DCE-MRI). Importantly, this work supports perivascular convection along penetrating blood vessels.

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Perivascular (Virchow–Robin) spaces

10.51271/kmj-0021 ◽

2021 ◽

pp. 86-89

Keyword(s):

Blood Vessels ◽

Shape Change ◽

Lymphatic Drainage ◽

Brain Regions ◽

Mechanical Trauma ◽

Normal Brain ◽

Perivascular Spaces ◽

Mr Images ◽

Lenticulostriate Artery ◽

The Brain

Perivascular spaces; also known as the Virchow-Robin Spaces, they are pleurally lined, interstitial fluid-filled areas that surround certain blood vessels in various organs, especially the perforating arteries in the brain, with an immunological function. Dilated perivascular spaces are divided into three types. The first of these is on the lenticulostriate artery, the second is in the cortex following the path of the medullary artery, and the third is in the midbrain. Perivascular spaces can be detected as areas of dilatation on MR images. Although a limited number of perivascular spaces can be seen in a normal brain, the increase in the number of these spaces has been associated with the incidence of various neurodegenerative diseases. Different theories have been suggested about the tendency of the perivascular spaces to expand. Current theories include mechanical trauma due to cerebrospinal fluid pulsing, elongation of penetrating blood vessels, unusual vascular permeability, and increased fluid exudation. In addition, the brain tissue atrophy that occurs with aging; It is thought to contribute to the widening of perivascular spaces by causing shrinkage of arteries, altered arterial wall permeability, obstruction of lymphatic drainage pathways and vascular demyelination. It is assumed that the clinical significance of the dilation tendencies of the perivascular spaces is based on shape change rather than size. These spaces have been mostly observed in brain regions such as corpus callosum, cingulate gyrus, dentate nucleus, substantia nigra and various arterial basins including lenticulostriate artery and mesencephalothalamic artery. In conclusion, when sections are taken on MR imaging, it is possible that perivascular spaces may be confused with microvascular diseases and some neurodegenerative changes. In addition, perivascular spaces can be seen without pathological significance. Therefore, it would be appropriate to investigate the etiological relationship by evaluating the radiological findings and clinical picture together.

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Two Cases of Atheroma of the Blood Vessels at the Base of the Brain, with Remarks upon the Symptoms, Diagnosis, Prognosis, and Pathological Condition in that Affection

Journal of Mental Science ◽

10.1192/bjp.16.73.52 ◽

1870 ◽

Vol 16 (73) ◽

pp. 52-58

Author(s):

J. T. Sabben

Keyword(s):

Blood Vessels ◽

Pathological Condition ◽

Cerebral Arteries ◽

General Paralysis ◽

Brain Substance ◽

The Brain

In publishing the following cases, recently under my charge, of mental derangement dependent upon atheromatous deposit in the coats of the larger cerebral arteries, without any apparent disease of the brain substance, I desire, if possible, to define the symptoms of that condition during life, so as to enable them to be distinguished from those of general paralysis, with which I believe them often to be confused.

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Meningeal Tumors Induced in Calves with the Bovine Cutaneous Papilloma Virus

Pathologia veterinaria ◽

10.1177/030098586900600204 ◽

1969 ◽

Vol 6 (2) ◽

pp. 135-145 ◽

Cited By ~ 3

Author(s):

D. F. Brobst ◽

G. C. Dulac

Keyword(s):

Blood Vessels ◽

Viral Antigen ◽

Papilloma Virus ◽

Meningeal Tumors ◽

The Brain

Fibromatous tumors were induced in the meninges of calves by inoculating the meninges with a suspension of bovine cutaneous papillomas or by implanting bovine cutaneous papillomas into the brain. Meningeal tumors were observed to occur as early as 20 days after inoculation. Meningeal tumors from calves killed 90 and 145 days after inoculation extended into the brain along the course of blood vessels. Metastasis, however, was not observed. Evidence that the induced meningeal tumors contained viral antigen was lacking.

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Blood Vessels in the Brain: A Signaling Hub in Brain Tumor Inflammation

The Blood Brain Barrier and Inflammation ◽

10.1007/978-3-319-45514-3_11 ◽

2017 ◽

pp. 253-277 ◽

Cited By ~ 2

Author(s):

Sylvaine Guerit ◽

Stefan Liebner

Keyword(s):

Brain Tumor ◽

Blood Vessels ◽

Tumor Inflammation ◽

The Brain

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Solute transport and reaction in porous electrodes at high Schmidt numbers

Journal of Fluid Mechanics ◽

10.1017/jfm.2020.344 ◽

2020 ◽

Vol 896 ◽

Cited By ~ 2

Author(s):

Dario Maggiolo ◽

Francesco Picano ◽

Filippo Zanini ◽

Simone Carmignato ◽

Massimo Guarnieri ◽

...

Keyword(s):

Solute Transport ◽

Porous Electrodes ◽

Schmidt Numbers ◽

Image Position

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

Neurosurgery ◽

10.1093/neuros/nyx417.119 ◽

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.

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