Two-Photon Imaging of Cortical Surface Microvessels Reveals a Robust Redistribution in Blood Flow after Vascular Occlusion

Schaffer, Chris B.; Friedman, Beth; Nishimura, Nozomi; Schroeder, Lee F.; Tsai, Philbert S.; Ebner, Ford F.; Lyden, Patrick D.; Kleinfeld, David

doi:10.1371/journal.pbio.0040022

Cited by 357 publications

(385 citation statements)

References 59 publications

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“…Finally, as the total flux is conserved, the total input arteriolar/output veinular fluxes are the same. This prediction is not contradictory with the observation of lower blood velocity in the veins at the cortical surface (Schaffer et al, 2006), as the diameter of pial veins is much larger than that of penetrating veins and of pial arteries.…”

Section: Blood Flow Distributionsupporting

confidence: 52%

Cerebral Blood Flow Modeling in Primate Cortex

Guibert

Fonta

Plouraboué

2010

J Cereb Blood Flow Metab

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We report new results on blood flow modeling over large volumes of cortical gray matter of primate brain. We propose a network method for computing the blood flow, which handles realistic boundary conditions, complex vessel shapes, and complex nonlinear blood rheology. From a detailed comparison of the available models for the blood flow rheology and the phase separation effect, we are able to derive important new results on the impact of network structure on blood pressure, hematocrit, and flow distributions. Our findings show that the network geometry (vessel shapes and diameters), the boundary conditions associated with the arterial inputs and venous outputs, and the effective viscosity of the blood are essential components in the flow distribution. In contrast, we show that the phase separation effect has a minor function in the global microvascular hemodynamic behavior. The behavior of the pressure, hematocrit, and blood flow distributions within the network are described through the depth of the primate cerebral cortex and are discussed.

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Section: Blood Flow Distributionsupporting

confidence: 52%

Cerebral Blood Flow Modeling in Primate Cortex

Guibert

Fonta

Plouraboué

2010

J Cereb Blood Flow Metab

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“…An alternative approach is in vivo high resolution optical imaging and multiphoton microscopy [92]. This technique has a far superior microscopic resolution; however, a major weakness of this approach is the relatively low tissue penetration (»500 m) that limits the imaging of the brain after ischemia to the examination of the cerebral cortex [72,123].…”

Section: Live Imaging: Development Of Novel Experimental Approaches Tmentioning

confidence: 99%

Inflammation, plasticity and real-time imaging after cerebral ischemia

2009

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With an incidence of approximately 350 in 100,000, stroke is the third leading cause of death and a major cause of disability in industrialized countries. At present, although progress has been made in understanding the molecular pathways that lead to ischemic cell death, the current clinical treatments remain poorly eVective. There is mounting evidence that inXammation plays an important role in cerebral ischemia. Experimentally and clinically, brain response to ischemic injury is associated with an acute and prolonged inXammatory process characterized by the activation of resident glial cells, production of inXammatory cytokines as well as leukocyte and monocyte inWltration in the brain, events that may contribute to ischemic brain injury and aVect brain recovery and plasticity. However, whether the post-ischemic inXammatory response is deleterious or beneWcial to brain recovery is presently a matter of debate and controversies. Here, we summarize the current knowledge on the molecular mechanisms underlying post-ischemic neuronal plasticity and the potential role of inXammation in regenerative processes and functional recovery after stroke. Furthermore, because of the dynamic nature of the brain inXammatory response, we highlight the importance of the development of novel experimental approaches such as real-time imaging. Finally, we discuss the novel transgenic reporter mice models that have allowed us to visualize and to analyze the processes such as neuroinXammation and neuronal repair from the ischemic brains of live animals.

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“…While intravital microscopy can probe the microcirculation in superficial tissues (8), magnetic resonance imaging (MRI) can probe functionally relevant properties of the microcirculation of living tissues deep within the body (6) using various contrast agents or signal mechanisms. Although they lack the spatial and temporal resolution of optical methods, MRI methods can retrieve indirect information about the microcirculatory bed by using either magnetic susceptibility effects or blood displacement effects.…”

mentioning

confidence: 99%

Intravoxel partially coherent motion technique: Characterization of the anisotropy of skeletal muscle microvasculature

Karampinos

King

Sutton

et al. 2010

Magnetic Resonance Imaging

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Purpose: To propose a reformulation of the intravoxel incoherent motion (IVIM) technique exploiting the low bvalue diffusion-weighted imaging regime that can characterize microcirculation of tissues perfused with partially coherent blood flow. Materials and Methods:The new methodology, termed intravoxel partially coherent motion (IVPCM) technique, is suitable for probing microcirculation in tissues with ordered microvasculature, such as skeletal muscle. We employ a subvoxel model utilizing a randomly oriented bundle of straight vessels whose orientation statistics are characterized by a Fisher axial distribution with concentration parameter K quantifying the anisotropy of the distribution (K ¼ 0 indicates isotropic capillary orientation). The methodology is first validated with a proof-of-principle phantom experiment and is then applied to analyze the microvasculature of human calf muscle at rest. Results:The microcirculatory part of the diffusionweighted signal at b < 200 s/mm 2 is anisotropic. The variation of the diffusion-weighted signal with b-value exhibits stronger deviation from the expected monoexponential decay when the diffusion encoding gradient is applied parallel to the mean myofiber direction in the calf muscle of three healthy volunteers. The application of the model to data from the medial gastrocnemius and the soleus of the three volunteers gives results within the expected range for the mean microvascular volume fraction, the mean microflow velocity, and the parameter K. Conclusion:The proposed methodology has the capability of characterizing the anisotropy of the capillary network in vivo in a manner analogous to the capability of high b-value diffusion to characterize the anisotropy of muscle fibers.

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Two-Photon Imaging of Cortical Surface Microvessels Reveals a Robust Redistribution in Blood Flow after Vascular Occlusion

Cited by 357 publications

References 59 publications

Cerebral Blood Flow Modeling in Primate Cortex

Cerebral Blood Flow Modeling in Primate Cortex

Inflammation, plasticity and real-time imaging after cerebral ischemia

Intravoxel partially coherent motion technique: Characterization of the anisotropy of skeletal muscle microvasculature

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