Optical spectroscopy improves predictiveassessment of kidney function5 May 2017

Figure 8, showing kidney function after ischemic injury.doi:10.1117/1.JBO.22.5.056001. Credit: The authors

A new technique developed by researchers atLawrence Livermore National Lab promises toimprove accuracy and lower costs of real-timeassessment of kidney function, reports an articlepublished this week by SPIE, the internationalsociety for optics and photonics, in the Journal ofBiomedical Optics.

The paper, published 3 May and accessible viaopen access, explores the use of multimodalautofluorescence and light scattering to evaluatefunctional changes in the kidneys after ischemicinjury. Conditions including accumulated arterialplaque or blood clots restrict the flow of oxygenand glucose to organs, and prolonged periods ofsuch ischemia can compromise function.

In "Predictive assessment of kidney functionalrecovery following ischemic injury using opticalspectroscopy," the authors report on theirevaluation of various optical signatures to predictkidney viability and suggest a noncontact approachto provide clinically useful information in real time.

While other current work in this area usesexpensive multiphoton and laser-based techniques,the authors reduced expenses by switching tocamera-based imaging.

Currently, there is no real-time tool to measure thedegree of ischemic injury incurred in tissue or topredict the return of its function. The inability todecisively determine tissue functional status runstwo great risks: that dysfunctional tissue may betransplanted, increasing the morbidity and mortalityof the patient; and that much-needed functionalkidney tissue may be discarded.

In their study, Rajesh Raman of LawrenceLivermore National Lab and co-authors ChristopherPivetti and Christoph Troppmann of the Universityof California Davis, Rajendra Ramsamooj ofCalifornia Northstate University, and StavrosDemos of Lawrence Livermore acquiredautofluorescence images of kidneys in vivo under355, 325, and 266 nm illumination. Light-scatteringimages were collected at the excitationwavelengths while using a relatively narrow bandlight centered at 500 nm.

The images were simultaneously recorded using amultimodal optical imaging system. The recordedsignals were then analyzed to obtain timeconstants, which were correlated to kidneydysfunction as determined by a subsequentsurvival study and histopathological analysis.

Analysis of the light-scattering andautofluorescence images suggests that variationsin tissue microstructure, fluorophore emission, andblood absorption spectral characteristics, combinedwith vascular response, contribute to the behaviorof the recorded signals. These are used to obtaintissue functional information and enable the abilityto predict post-transplant kidney function.

This information can also be applied to theprediction of kidney failure when visual observation

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cannot, almost immediately following an injury.

Reviewers of the study suggested other promisingapplications for future development, and envisionedthis approach being used as a screening tool forassessing kidney viability prior to transplant. Inparticular, they said, these cost-effective screeningmethods could benefit healthcare in developingcountries.

Multimodal imaging also has provided insights intoother physiological events that may occur duringischemia and reperfusion.

"This work's exceptional value lies in the realizationof a workable practical system that has excellentpotential to be adopted in field situations," saidjournal associate editor Andreas Mandelis(University of Toronto).

More information: Rajesh N. Raman et al,Predictive assessment of kidney functionalrecovery following ischemic injury using opticalspectroscopy, Journal of Biomedical Optics (2017). DOI: 10.1117/1.JBO.22.5.056001

Provided by SPIEAPA citation: Optical spectroscopy improves predictive assessment of kidney function (2017, May 5)retrieved 26 May 2022 from https://phys.org/news/2017-05-optical-spectroscopy-kidney-function.html

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