Optical spectroscopy approach for the predictive assessment of kidney functional recovery following ischemic injury

Rajesh N. Raman, Christopher D. Pivetti, Alexander M. Rubenchik, Dennis L. Matthews, Christoph Troppmann, Stavros G Demos

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


Tissue that has undergone significant yet unknown amount of ischemic injury is frequently encountered in organ transplantation and trauma clinics. With no reliable real-time method of assessing the degree of injury incurred in tissue, surgeons generally rely on visual observation which is subjective. In this work, we investigate the use of optical spectroscopy methods as a potentially more reliable approach. Previous work by various groups was strongly suggestive that tissue autofluorescence from NADH obtained under UV excitation is sensitive to metabolic response changes. To test and expand upon this concept, we monitored autofluorescence and light scattering intensities of injured vs. uninjured rat kidneys via multimodal imaging under 355 nm, 325 nm, and 266 nm excitation as well as scattering under 500 nm illumination. 355 nm excitation was used to probe mainly NADH, a metabolite, while 266 nm excitation was used to probe mainly tryptophan to correct for non-metabolic signal artifacts. The ratio of autofluorescence intensities derived under these two excitation wavelengths was calculated and its temporal profile was fit to a relaxation model. Time constants were extracted, and longer time constants were associated with kidney dysfunction. Analysis of both the autofluorescence and light scattering images suggests that changes in microstructure tissue morphology, blood absorption spectral characteristics, and pH contribute to the behavior of the observed signal which may be used to obtain tissue functional information and offer predictive capability.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
StatePublished - 2010
EventOptical Biopsy VII - San Francisco, CA, United States
Duration: Jan 25 2010Jan 28 2010


OtherOptical Biopsy VII
Country/TerritoryUnited States
CitySan Francisco, CA


  • In vivo
  • Ischemia
  • Kidney
  • Reperfusion
  • Spectral imaging

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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