Mapping flow velocity in the human retinal capillary network with pixel intensity cross correlation.

PLoS One

Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia.

Published: February 2020

AI Article Synopsis

  • A new method called PIX is introduced for measuring cellular velocity in small retinal blood vessels using adaptive optics, which analyzes pixel intensity profiles over time to assess flow direction.
  • The method involves comparing each pixel’s intensity with others after a time shift to identify the most similar pixel, calculating the velocity by measuring displacement over time.
  • PIX shows improved accuracy and efficiency in capturing flow dynamics compared to existing techniques like particle image velocimetry and manual tracking, demonstrating its potential in retinal studies.

Article Abstract

We present a new method for determining cellular velocity in the smallest retinal vascular networks as visualized with adaptive optics. The method operates by comparing the intensity profile of each movie pixel with that of every other pixel, after shifting in time by one frame. The time-shifted pixel which most resembles the reference pixel is deemed to be a 'source' or 'destination' of flow information for that pixel. Velocity in the transverse direction is then calculated by dividing the spatial displacement between the two pixels by the inter-frame period. We call this method pixel intensity cross-correlation, or "PIX". Here we compare measurements derived from PIX to two other state-of-the-art algorithms (particle image velocimetry and the spatiotemporal kymograph), as well as to manually tracked cell data. The examples chosen highlight the potential of the new algorithm to substantially improve spatial and temporal resolution, resilience to noise and aliasing, and assessment of network flow properties compared with existing methods.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6592569PMC
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0218918PLOS

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