Preclinical evaluation of spatial frequency domain-enabled wide-field quantitative imaging for enhanced glioma resection

J Biomed Opt. 2017 Jul 1;22(7):76007. doi: 10.1117/1.JBO.22.7.076007.

Abstract

5-Aminolevelunic acid-induced protoporphyrin IX (PpIX) fluorescence-guided resection (FGR) enables maximum safe resection of glioma by providing real-time tumor contrast. However, the subjective visual assessment and the variable intrinsic optical attenuation of tissue limit this technique to reliably delineating only high-grade tumors that display strong fluorescence. We have previously shown, using a fiber-optic probe, that quantitative assessment using noninvasive point spectroscopic measurements of the absolute PpIX concentration in tissue further improves the accuracy of FGR, extending it to surgically curable low-grade glioma. More recently, we have shown that implementing spatial frequency domain imaging with a fluorescent-light transport model enables recovery of two-dimensional images of [PpIX], alleviating the need for time-consuming point sampling of the brain surface. We present first results of this technique modified for <italic<in vivo</italic< imaging on an RG2 rat brain tumor model. Despite the moderate errors in retrieving the absorption and reduced scattering coefficients in the subdiffusive regime of 14% and 19%, respectively, the recovered [PpIX] maps agree within 10% of the point [PpIX] values measured by the fiber-optic probe, validating its potential as an extension or an alternative to point sampling during glioma resection.

MeSH terms

  • Animals
  • Fluorescence
  • Glioma / diagnostic imaging*
  • Glioma / surgery*
  • Protoporphyrins / metabolism
  • Rats
  • Reproducibility of Results

Substances

  • Protoporphyrins