Artikel
Fluorescence lifetime imaging of brain and brain tumour tissue by time-resolved multiphoton excitation microscopy
Fluoreszenzlebenszeitdarstellung von Hirn- und Hirntumorgewebe durch 4D multiphotonen-angeregte Fluoreszenzmikroskopie
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Veröffentlicht: | 8. Mai 2006 |
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Gliederung
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Objective: Multiphoton excited in vivo fluorescent microscopy is a laser based technology that allows subcellular resolution of native tissues in situ. We have previously demonstrated that multiphoton microscopy allows a discrimination of different cell types, neurons, glia, or tumor cells and visualization of organelles. In addition selective excitation of endogenous biomolecules offers means of imaging cellular metabolism or cellular function in situ. Here we demonstrate that the excitation profiles and lifetimes of endogenous fluorophores may be used to discriminate tumor cells and elements of normal brain.
Methods: Invasive and non-invasive experimental gliomas were analyzed by multiphoton microscopy and corresponding samples were processed for conventional histology. Biopsies of human brain tumors were obtained during resection of glial tumors and biopsy sites were documented using neuronavigation. The native tissue blocks were analyzed by multiphoton microscopy and the microanatomy of specimens was correlated with MRI findings and conventional histology.
Results: Various elements of normal murine brain anatomy showed characteristic multiphoton ecxited intensity- and fluorescent lifetime profiles, which could be clearly differentiated from experimental glioma tissue. Fluorescent lifetime imaging of human ex vivo brain tumor specimens demonstrated visualization of the cellular composition of solid tumor allowing the discrimination of individual tumor cells, tumor cell clusters and vasculature. Acquisition of three dimensional data arrays of specimens obtained from solid tumor and the wall of the resection cavity showed that this technology may be used to quantify the density of tumor cells per native tissue volume, for example within the wall of the resection cavity.
Conclusions: We have demonstrated that multiphoton microscopy and fluorescent lifetime imaging can discriminate tumor and normal brain. This non-invasive imaging technology can be used to quantify the density of invasive tumor cells in native tissue and may therefore provide a future tool in the in situ detection of residual tumor during brain tumor surgery.