Mesoscopic multispectral imaging and its applications on characterization of tissue microvascularity and nano/microstructures
Abstract
The ability to non-invasively characterize tissue microvascularity and microstructures in a large area can provide an invaluable tool in various preclinical and clinical applications. Tissue properties are often spatially heterogeneous in a large area. Conventional microscopic imaging techniques are, however, not adequate to visualize detailed field alterations due to a limited field of view. To overcome this fundamental limitation, we have developed a mesoscopic (i.e. between microscopic and macroscopic) spectroscopic imaging modality. We have conducted a series of biological studies to establish the utilization of our mesoscopic imaging modality for addressing critical biological and clinical problems. First, we have demonstrated that the combination of a back-directional (angular) gating configuration and multispectral measurements allows us to take advantage of intrinsic tissue properties, such as scattering anisotropy and hemoglobin absorption, and to achieve an enhanced imaging contrast, resolution, and depth. Second, to assess microvascular alterations as well as to provide new insights about field cancerization during early carcinogenesis, we have quantified spatial and temporal changes in dermal microvascular hemoglobin content in experimental skin carcinogenesis, including photocarcinogenesis. Spatial and temporal analysis of focal areas of inflammatory hyperemia can predict not only whether tumors will form, but also where they will form. We have also assessed effects of topical celecoxib treatment as a chemoprevention strategy. The chemopreventive activity of celecoxib correlates with its ability to suppress formation of hyperemic foci. Third, we have further applied our imaging approach to visualize spatial heterogeneity of tissue microstructural alterations at the scales of hundreds of nanometers in other biological tissues and biomaterials. We have demonstrated the feasibility of our imaging methods for surgical guidance and biomaterial characterization. Overall, the advantages of our imaging approaches are the large field of view for whole-field assessments, the use of endogenous tissue contrasts, the sensitivity to subtle alterations of intrinsic tissue properties, and the simplicity of the instrumentation. Thus, we envision that the newly-developed imaging methods will have the potential for broad utilization to characterize tissue properties in a variety of research and industrial settings.
Degree
Ph.D.
Advisors
Kim, Purdue University.
Subject Area
Biomedical engineering
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