Three-dimensional visualization of the renal microcirculation using laser speckle contrast imaging

Master thesis (2022)

Authors

L.S. van Ooijen Mechanical Engineering

Contributors

J. Dankelman Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 1)
R.W.F. de Bruin Erasmus MC (supervisor 1)
F.J.H. Gijsen Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 2)
Y. Fang Erasmus MC (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2022 Lisanne van Ooijen
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Published Date

02-12-2022

Language

English

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Faculty

Mechanical Engineering

Abstract

In the Netherlands, over 12%
of the population has chronic kidney damage resulting in about 2000 patients
with renal failure each year. Replacement of the kidney function by
transplantation is desired, but due to a shortage of donor kidneys, the
waiting list for a transplant is long. Extending the criteria that donors
must meet can reduce the waiting list, but it is necessary that these organs
are still of sufficient quality. Initial studies indicate that using the
normothermic machine perfusion (NMP) preservation method results in better
transplant outcomes and possibly improves donor kidneys’ quality.
The quality of the organ during NMP can be used as a potential biomarker
for graft survival. However, what is still missing is a reliable way to
test the quality during NMP. Laser speckle contrast imaging (LSCI) is
a non-invasive, continuous, real-time imaging technique that can visualize
tissue perfusion. In this study, a method is designed to visualize the
perfusion over the entire surface of normothermic machine-perfused kidneys
using LSCI. A three-dimensional (3D) perfusion model is developed based on
two-dimensional (2D) LSCI images. This method can then be used to determine the
quality of the perfusion of donor kidneys before they are transplanted.

A method is designed to obtain LSCI data of porcine kidneys undergoing NMP.
Data is recorded during the first 100 minutes of NMP to evaluate the
relationship between renal arterial blood flow and perfusion. The kidneys are
then placed in six different positions from which LSCI data is collected. Using
shape from silhouettes, a 3D model is made from each kidney. The 2D LSCI
data is given depth using the 3D model by assigning each pixel a 3D coordinate.
The perfusion model is validated by comparing the perfusion model for the
situation where no ischemia is present in the kidney and the situation
where ischemia is present in the kidney. 

The designed method and setup made it possible to
obtain perfusion data over the vast majority of the surface of the
kidneys. Further, the results show a positive linear correlation between measured perfusion
and arterial blood flow in each kidney. With the collected perfusion data,
a 3D visualization was made. 3D models from all kidneys could be used for
this. The 3D visualization is represented as a point cloud and allows for easy
and fast viewing of the perfusion over the entire surface.

Validating the model with induced ischemia showed that
the 3D visualization can indicate significant perfusion differences caused
by ischemia. This makes LSCI a promising method for determining perfusion
quality.