scholarly journals Characterization of cerebral blood flow dynamics with multiscale entropy

2017 ◽  
Vol 10 (05) ◽  
pp. 1743005 ◽  
Author(s):  
Alexey N. Pavlov ◽  
Arkady S. Abdurashitov ◽  
Olga N. Pavlova ◽  
Maria V. Ulanova ◽  
Anastasia A. Bodrova ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Dynamics ◽  
Laser Speckle ◽  
Multiscale Entropy ◽  
Cerebral Veins ◽  
Contrast Imaging ◽  
Speckle Contrast ◽  
Sound Exposure ◽  
Blood Flow Dynamics

Based on the laser speckle contrast imaging (LSCI) and the multiscale entropy (MSE), we study in this work the blood flow dynamics at the levels of cerebral veins and the surrounding network of microcerebral vessels. We discuss how the phenylephrine-related acute peripheral hypertension is reflected in the cerebral circulation and show that the observed changes are scale-dependent, and they are significantly more pronounced in microcerebral vessels, while the macrocerebral dynamics does not demonstrate authentic inter-group distinctions. We also consider the permeability of blood–brain barrier (BBB) and study its opening caused by sound exposure. We show that alterations associated with the BBB opening can be revealed by the analysis of blood flow at the level of macrocerebral vessels.

scholarly journals Nephron blood flow dynamics measured by laser speckle contrast imaging

2011 ◽  
Vol 300 (2) ◽  
pp. F319-F329 ◽  
Author(s):  
Niels-Henrik Holstein-Rathlou ◽  
Olga V. Sosnovtseva ◽  
Alexey N. Pavlov ◽  
William A. Cupples ◽  
Charlotte Mehlin Sorensen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Signal Transmission ◽  
Experimental Studies ◽  
Flow Dynamics ◽  
Laser Speckle ◽  
Tubuloglomerular Feedback ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast ◽  
Blood Flow Dynamics

Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50–100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic techniques for extracting the desired data and for examining them for evidence of nephron synchronization. Synchronized TGF oscillations were detected in pairs or triplets of nephrons. The amplitude and the frequency of the oscillations changed with time, as did the patterns of synchronization. Synchronization may take place among nephrons not immediately adjacent on the surface of the kidney.

Enhancing vascular visualization in laser speckle contrast imaging of blood flow using multi-focus image fusion

2018 ◽  
Vol 12 (1) ◽  
pp. e201800100 ◽  
Author(s):  
Wenzhi Lv ◽  
Yang Wang ◽  
Xiao Chen ◽  
Xiaoxi Fu ◽  
Jinling Lu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Image Fusion ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast ◽  
Focus Image
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