Abstract TMP56: Mapping the Dynamics of Brain Perfusion During and Following Transient Middle Cerebral Artery Occlusion (tMCAo) in the Rat Using Functional Ultrasound (fUS)

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Jean-Claude Baron ◽  
Clement Brunner ◽  
Clothilde Isabel ◽  
Abraham Martin ◽  
Clara Dussaux ◽  
...  
Keyword(s):  
Real Time ◽  
Time Course ◽  
Cerebral Blood Volume ◽  
Quantitative Imaging ◽  
Neuronal Loss ◽  
Brain Perfusion ◽  
Artery Occlusion ◽  
Experimental Stroke ◽  
Wide Field ◽  
Spatiotemporal Resolution

Introduction: Following MCAo, tissue outcome varies depending on depth and duration of hypoperfusion and efficiency of reperfusion. However, the precise time-course of these events in relation to tissue and behavioral outcome remains unsettled due to lack of a wide field-of-view quantitative imaging technique able to map perfusion in the rodent brain at high spatiotemporal resolution. Here we used fUS, a novel approach to map cerebral blood volume (CBV) without contrast agent. Hypothesis: fUS will allow quantitative, near real-time mapping of CVB during and after tMCAo. Methods: 45min filament tMCAo was induced in adult SD rats; sham rats were also used. fUS was used to map the penetrating arterioles and venules of the ipsi- and contra-lateral motor (M1-2) and somatosensory (S1) cortex in coronal sections across the MCA territory at 80μm resolution. Three-min coronal scans were taken at different levels before, during and immediately after MCAo, and at 3 and 6 days thanks to a thinned-skull preparation. CBV was expressed relative to mirror ROI. In addition, a 1-hr movie (one frame/5s) was taken starting a few mins after reperfusion. Serial Neuroscore and 2 sensorimotor tasks were given over 3w post-MCAo, and then NeuN, IBa1 and GFAP immunofluorescence (IF) at post-mortem. Results: fUS showed a ∼80% CBV reduction in S1 during occlusion (p<0.001; n=7), with partial (∼60%, p<0.001) return of CBV on reperfusion, followed by a full return at days 3 and 6. As expected for this model, similar but less conspicuous CBV changes prevailed in M1-2. Continuous reperfusion was depicted in 5/7 rats (slope range: 8-25%/hr relative to prior CBV), but not in 2 rats. There were no significant changes in behavior relative to the sham group (n=4), and IF showed no infarction but marked selective neuronal loss (SNL) in the striatum in 5/7 rats and milder cortical SNL in 4/7 rats. Conclusions: fUS efficiently mapped the acute changes in CBV during occlusion and following reperfusion with high spatio-temporal resolution, allowing the charting of fine tissue reperfusion dynamics in the individual rat. fUS is ideal to longitudinally map real-time cerebral perfusion in experimental stroke from the hyper-acute through to the chronic stage.

scholarly journals Neurofilament Proteolysis after Focal Ischemia; When Do Cells Die after Experimental Stroke?

1999 ◽  
Vol 19 (6) ◽  
pp. 652-660 ◽  
Author(s):  
Jaroslaw Aronowski ◽  
Ki-Hyun Cho ◽  
Roger Strong ◽  
James C. Grotta
Keyword(s):  
Time Course ◽  
Infarct Volume ◽  
Focal Ischemia ◽  
Cellular Damage ◽  
Experimental Stroke ◽  
Infarct Core ◽  
Similar Time ◽  
The Core ◽  
Tetrazolium Staining ◽  
Previous Demonstration

To determine the occurrence and time-course of presumably irreversible subcellular damage after moderate focal ischemia, rats were subjected to 1, 3, 6, 9, or 24 hours of permanent unilateral middle cerebral and common carotid occlusion or 3 hours of reversible occlusion followed by 3, 6, or 21 hours of reperfusion. The topography and the extent of damage were analyzed with tetrazolium staining and immunoblot using an antibody capable of detecting breakdown of neurofilament. Neurofilament proteolysis began after 3 hours in the infarct core but was still incomplete in penumbral regions up to 9 hours. Similarly, tetrazolium-staining abnormalities were observed in the core of 50% of animals after 3 hours of ischemia. At 6 hours of permanent ischemia, infarct volume was maximal, and further prolongation of occlusion to 9 or 24 hours did not increase abnormal tetrazolium staining. In contrast to permanent ischemia and in agreement with the authors' previous demonstration of “reperfusion injury” in this model, prolongation of reperfusion from 3 hours to 6 and 21 hours after 3 hours of reversible occlusion gradually augmented infarct volume by 203% and 324%, respectively. Neurofilament proteolysis initiated approximately 3 hours after ischemia was quantitatively greatest in the core and extended during reperfusion to incorporate penumbra with a similar time course to that of tetrazolium abnormalities. These data demonstrate that, at least as measured by neurofilament breakdown and mitochondrial failure, extensive cellular damage is not present in penumbral regions for up to 9 hours, suggesting the potential for rescuing these regions by appropriate and timely neuroprotective strategies.

scholarly journals A Deep Learning Approach to Downscale Geostationary Satellite Imagery for Decision Support in High Impact Wildfires

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 294
Author(s):  
Nicholas F. McCarthy ◽  
Ali Tohidi ◽  
Yawar Aziz ◽  
Matt Dennie ◽  
Mario Miguel Valero ◽  
...  
Keyword(s):  
Deep Learning ◽  
Decision Support ◽  
Real Time ◽  
Forest Fires ◽  
Wildland Fire ◽  
Fire Spread ◽  
Low Earth Orbit ◽  
Practical Implementation ◽  
Spatiotemporal Resolution ◽  
Active Fire

Scarcity in wildland fire progression data as well as considerable uncertainties in forecasts demand improved methods to monitor fire spread in real time. However, there exists at present no scalable solution to acquire consistent information about active forest fires that is both spatially and temporally explicit. To overcome this limitation, we propose a statistical downscaling scheme based on deep learning that leverages multi-source Remote Sensing (RS) data. Our system relies on a U-Net Convolutional Neural Network (CNN) to downscale Geostationary (GEO) satellite multispectral imagery and continuously monitor active fire progression with a spatial resolution similar to Low Earth Orbit (LEO) sensors. In order to achieve this, the model trains on LEO RS products, land use information, vegetation properties, and terrain data. The practical implementation has been optimized to use cloud compute clusters, software containers and multi-step parallel pipelines in order to facilitate real time operational deployment. The performance of the model was validated in five wildfires selected from among the most destructive that occurred in California in 2017 and 2018. These results demonstrate the effectiveness of the proposed methodology in monitoring fire progression with high spatiotemporal resolution, which can be instrumental for decision support during the first hours of wildfires that may quickly become large and dangerous. Additionally, the proposed methodology can be leveraged to collect detailed quantitative data about real-scale wildfire behaviour, thus supporting the development and validation of fire spread models.

MRI investigation of vascular remodeling for heterogeneous edema lesions in subacute ischemic stroke rat models: Correspondence between cerebral vessel structure and function

2021 ◽  
pp. 0271678X2110291
Author(s):  
MungSoo Kang ◽  
Seokha Jin ◽  
HyungJoon Cho
Keyword(s):  
Vascular Remodeling ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Light Sheet ◽  
Artery Occlusion ◽  
Strong Positive Correlation ◽  
Cerebral Vessel ◽  
Rat Models ◽  
Apparent Diffusion Coefficient Values ◽  
Vessel Structure

The spatial heterogeneity in the temporal occurrence of pseudo-normalization of MR apparent diffusion coefficient values for ischemic lesions may be related to morphological and functional vascular remodeling. As the area of accelerated pseudo-normalization tends to expand faster and more extensively into the chronic stage, detailed vascular characterization of such areas is necessary. During the subacute stage of transient middle cerebral artery occlusion rat models, the morphological size of the macrovasculature, microvascular vessel size index (VSI), and microvessel density (MVD) were quantified along with functional perfusion measurements of the relative cerebral blood flow (rCBF) and mean transit time (rMTT) of the corresponding areas (33 cases for each parameter). When compared with typical pseudo-normalization lesions, early pseudo-normalization lesions exhibited larger VSI and rCBF (p < 0.001) at reperfusion days 4 and 7, along with reduced MVD and elongated rMTT (p < 0.001) at reperfusion days 1, 4, and 7. The group median VSI and rCBF exhibited a strong positive correlation (r = 0.92), and the corresponding MVD and rMTT showed a negative correlation (r = −0.48). Light sheet fluorescence microscopy images were used to quantitatively validate the corresponding MRI-derived microvascular size, density, and cerebral blood volume.

Processing Panorama Video in Real-time

2014 ◽  
Vol 08 (02) ◽  
pp. 209-227 ◽  
Author(s):  
Håkon Kvale Stensland ◽  
Vamsidhar Reddy Gaddam ◽  
Marius Tennøe ◽  
Espen Helgedagsrud ◽  
Mikkel Næss ◽  
...  
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
Low Cost ◽  
Video Camera ◽  
Wide Field ◽  
High Data ◽  
Data Rates ◽  
Camera Arrays ◽  
Analysis System ◽  
Performance Results

There are many scenarios where high resolution, wide field of view video is useful. Such panorama video may be generated using camera arrays where the feeds from multiple cameras pointing at different parts of the captured area are stitched together. However, processing the different steps of a panorama video pipeline in real-time is challenging due to the high data rates and the stringent timeliness requirements. In our research, we use panorama video in a sport analysis system called Bagadus. This system is deployed at Alfheim stadium in Tromsø, and due to live usage, the video events must be generated in real-time. In this paper, we describe our real-time panorama system built using a low-cost CCD HD video camera array. We describe how we have implemented different components and evaluated alternatives. The performance results from experiments ran on commodity hardware with and without co-processors like graphics processing units (GPUs) show that the entire pipeline is able to run in real-time.

scholarly journals Preclinical evaluation of spatial frequency domain-enabled wide-field quantitative imaging for enhanced glioma resection

2017 ◽  
Vol 22 (7) ◽  
pp. 076007 ◽  
Author(s):  
Mira Sibai ◽  
Carl Fisher ◽  
Israel Veilleux ◽  
Jonathan T. Elliott ◽  
Frederic Leblond ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Frequency Domain ◽  
Quantitative Imaging ◽  
Wide Field ◽  
Preclinical Evaluation ◽  
Glioma Resection ◽  
Spatial Frequency Domain

Immunosuppressant quantification in intravenous microdialysate – towards novel quasi-continuous therapeutic drug monitoring in transplanted patients

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Susanne Weber ◽  
Sara Tombelli ◽  
Ambra Giannetti ◽  
Cosimo Trono ◽  
Mark O’Connell ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Real Time ◽  
Drug Monitoring ◽  
Time Course ◽  
Drug Dosage ◽  
Immunosuppressive Drug ◽  
Therapeutic Drug ◽  
Continuous Sampling ◽  
Real Time Analysis ◽  
Drug Concentrations

AbstractObjectivesTherapeutic drug monitoring (TDM) plays a crucial role in personalized medicine. It helps clinicians to tailor drug dosage for optimized therapy through understanding the underlying complex pharmacokinetics and pharmacodynamics. Conventional, non-continuous TDM fails to provide real-time information, which is particularly important for the initial phase of immunosuppressant therapy, e.g., with cyclosporine (CsA) and mycophenolic acid (MPA).MethodsWe analyzed the time course over 8 h of total and free of immunosuppressive drug (CsA and MPA) concentrations measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 16 kidney transplant patients. Besides repeated blood sampling, intravenous microdialysis was used for continuous sampling. Free drug concentrations were determined from ultracentrifuged EDTA-plasma (UC) and compared with the drug concentrations in the respective microdialysate (µD). µDs were additionally analyzed for free CsA using a novel immunosensor chip integrated into a fluorescence detection platform. The potential of microdialysis coupled with an optical immunosensor for the TDM of immunosuppressants was assessed.ResultsUsing LC-MS/MS, the free concentrations of CsA (fCsA) and MPA (fMPA) were detectable and the time courses of total and free CsA comparable. fCsA and fMPA and area-under-the-curves (AUCs) in µDs correlated well with those determined in UCs (r≥0.79 and r≥0.88, respectively). Moreover, fCsA in µDs measured with the immunosensor correlated clearly with those determined by LC-MS/MS (r=0.82).ConclusionsThe new microdialysis-supported immunosensor allows real-time analysis of immunosuppressants and tailor-made dosing according to the AUC concept. It readily lends itself to future applications as minimally invasive and continuous near-patient TDM.

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