Laser speckle contrast imaging: Theory, instrumentation and applications

Janaka Senarathna, Abhishek Rege, Nan Li, Nitish V. Thakor

Research output: Contribution to journalArticlepeer-review

Abstract

Laser Speckle Contrast Imaging (LSCI) is a wide field of view, non scanning optical technique for observing blood flow. Speckles are produced when coherent light scattered back from biological tissue is diffracted through the limiting aperture of focusing optics. Mobile scatterers cause the speckle pattern to blur; a model can be constructed by inversely relating the degree of blur, termed speckle contrast to the scatterer speed. In tissue, red blood cells are the main source of moving scatterers. Therefore, blood flow acts as a virtual contrast agent, outlining blood vessels. The spatial resolution ({\sim 10}~\mu{\rm m}) and temporal resolution (10 ms to 10 s) of LSCI can be tailored to the application. Restricted by the penetration depth of light, LSCI can only visualize superficial blood flow. Additionally, due to its non scanning nature, LSCI is unable to provide depth resolved images. The simple setup and non-dependence on exogenous contrast agents have made LSCI a popular tool for studying vascular structure and blood flow dynamics. We discuss the theory and practice of LSCI and critically analyze its merit in major areas of application such as retinal imaging, imaging of skin perfusion as well as imaging of neurophysiology.

Original languageEnglish (US)
Article number6422348
Pages (from-to)99-110
Number of pages12
JournalIEEE Reviews in Biomedical Engineering
Volume6
DOIs
StatePublished - 2013
Externally publishedYes

Keywords

  • Functional imaging
  • imaging of cortical spreading depression
  • imaging of stroke
  • laser speckle contrast imaging
  • retinal imaging
  • skin imaging

ASJC Scopus subject areas

  • Biomedical Engineering

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