How to Build a Laser Speckle Contrast Imaging (LSCI) System to Monitor Blood Flow

Summary

This video demonstrates how to build a Laser Speckle Contrast Imaging (LSCI) system that can easily be used to monitor blood flow.

Abstract

Laser Speckle Contrast Imaging (LSCI) is a simple yet powerful technique that is used for full-field imaging of blood flow. The technique analyzes fluctuations in a dynamic speckle pattern to detect the movement of particles similar to how laser Doppler analyzes frequency shifts to determine particle speed. Because it can be used to monitor the movement of red blood cells, LSCI has become a popular tool for measuring blood flow in tissues such as the retina, skin, and brain. It has become especially useful in neuroscience where blood flow changes during physiological events like functional activation, stroke, and spreading depolarization can be quantified. LSCI is also attractive because it provides excellent spatial and temporal resolution while using inexpensive instrumentation that can easily be combined with other imaging modalities. Here we show how to build a LSCI setup and demonstrate its ability to monitor blood flow changes in the brain during an animal experiment.

Protocol

1. Imaging Setup

1. A camera with a macro zoom lens should be mounted to a vertical stage or surgical microscope (Instead of a macro zoom lens, a microscope objective and lens or a simple two lens system could be used depending on the desired magnification).
2. Download appropriate software from our website to control the camera (http://bach.bme.utexas.edu/mediawiki/index.php/Software).
3. The camera software should be used to confirm an object is in focus at the desired height
4. A laser diode with a collimation kit should then be set up so that divergent laser light....

Discussion

In this video we have demonstrated how easy it is to build and use a laser speckle contrast imaging (LSCI) system to look at changes in blood flow. LSCI was developed in the 1980s as a way to generate maps of blood flow in the retina¹. While still used to image the retina and skin perfusion, it has become extremely popular as a technique to image blood flow in the brain². This is largely due to the excellent spatial and temporal resolution provided and the simplicity of the instrumentation. LSCI h.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Firewire camera	Basler	scA640-74f
Macro zoom lens	Edmund Scientific	NT58-240
Laser diode	Thorlabs Inc.	HL6501MG
Laser diode controller	Thorlabs Inc.	LDC201CU
The technique is versatile enough to be used with a wide range of equipment. The only things necessary to perform the experiment are a compatible camera with a lens, a laser diode of any type with a controller, and the provided software. A table of the specific equipment used in the video is included above. A complete list of additional parts that can be used in this experiment is found on our website, http://bach.bme.utexas.edu/mediawiki/index.php/Hardware