Comparison of Laser Speckle Contrast Imaging (LSCI) and Laser Doppler Imaging (LDI)

The microcirculation plays a fundamental role in the human body and it has been
shown as an essential determinant in many clinical scenarios such as shock
states, chronic and cardiac diseases. Microcirculation can be assessed directly
using laser-based techniques and intravital microscopes. When combined with
provocation tests, microvascular monitorization can be used to assess
microvascular function.

Laser-based techniques are consist of two different methods named laser doppler
imaging (LDI), laser speckle contrast imaging (LSCI). LSCI is a technique based
on speckle contrast analysis that provides an index of blood flux. No need for
skin contact, continuous and real-time assessment of the microcirculation led
the LSCI to be broadly used in clinical practice.
LDI is also a non-invasive diagnostic method used to measure blood flux of
tissue. The technique is based on measuring the doppler shift induced by moving
red blood cells to the illuminating coherent light. Iontophoresis is one of the
most commonly used provocation test to study the endothelium in terms of
endothelium-dependent and endothelium-independent vasodilation. Simultaneously
with LDI and LSCI are used to follow and assess the skin blood flux during
iontophoresis. Therefore, it provides a state to make a comparison between two
different laser-based techniques in terms of flux characteristics.

The accurate assessment of burn depth is a critical step in the management of
the burn-injured patient. Currently, LDI is the most widely used noninvasive
measurement tool for the assessment of burn wounds and the only technique that
has been approved by the U.S. Food and Drug Administration. However, LDI device
is rather costly, cumbersome and has a poor spatial resolution. LSCI measures
perfusion in a similar way, but it provides high quality images with a much
higher spatial resolution. In addition, LSCI is much quicker, maneuverable and
able to assess more larger skin areas. In order to use LSCI technique in
clinical practice of burn-injured patients, as a first step, linearity of LDI
and LSCI should be shown. In this study we aimed to compare LSCI and LDI with
iontophoresis and stepwise occlusion technique. So, we will be able to test the
linearity of devices over a large range of blood flux values.

o To test the linearity of the LSCI device (Perimed AB, Järfälla, Sweden) and
LDI device (Moor Instruments, Devon, UK) in a wide range of blood flux values
o To compare arbitrary units of two different kinds of laser-based devices and
to create a common and universal unit
o To create a color code, comparing LDI and LSCI

Single-center, prospective, observational and non-interventional study in the
Maastad Hospital, Rotterdam, The Netherlands

Microcirculation assessment is a non-invasive procedure, and there are no risks
associated with LSCI and LDI devices. Additional blood tests are not required.
The risks can be considered negligible, and the burden can be considered
minimal. Major side-effects are rare with using iontophoresis. However, minor
reactions such as itching, erythema and general irritation of the iontophoresis
skin surface are common during procedure. Discoloration of the skin may occur.