Multispectral imaging in biology and medicine: Slices of life

Abstract

Multispectral imaging (MSI) is currently in a period of transition from its role as an exotic technique to its being offered in one form or another by all the major microscopy manufacturers. This is because it provides solutions to some of the major challenges in fluorescence-based imaging, namely ameliorating the consequences of the presence of autofluorescence and the need to easily accommodate relatively high levels of signal multiplexing. MSI, which spectrally characterizes and computationally eliminates autofluorescence, enhances the signal-to-background dramatically, revealing otherwise obscured targets. While this article concentrates on examples derived from liquid-crystal tunable filter-based technology, the intent is to showcase the advantages of multispectral imaging in general. Some technologies used to generate multispectral images are compatible with only particular optical configurations, such as point-scanning laser confocal microscopy. Band-sequential approaches, such as those afforded by liquid-crystal tunable filters (LCTFs), can be conveniently coupled with a variety of imaging modalities, which, in addition to fluorescence microscopy, include brightfield (nonfluorescent) microscopy as well as small-animal, noninvasive in-vivo imaging. Brightfield microscopy is the chosen format for histopathology, which relies on immunohistochemistry to provide molecularly resolved clinical information. However, in contrast to fluorescent labels, multiple chromogens, if they spatially overlap, are much harder to separate and quantitate, unless MSI approaches are used. In-vivo imaging is a rapidly growing field with applications in basic biology, drug discovery, and clinical medicine. The sensitivity of fluorescence-based in-vivo imaging, as with fluorescence microscopy, can be limited by the presence of significant autofluorescence, a limitation which can be overcome through the utilization of MSI. q 2006 International Society for Analytical Cytology

Multispectral optical imaging combinedin situwith XPS or ToFSIMS and principal component analysis

“…[2] Light delivered to biological tissue undergoes multiple scattering from inhomogeneities within biological structures and absorption primarily in haemoglobin, melanin and water as it propagates through the tissue. Near-infrared (NIR) wavelengths in particular can be a very useful region of the optical spectrum for biomedical imaging.…”

“…in food product quality control) where the product being scanned moves on a conveyor under the line-scanning instrument. [2] Another approach is to sequentially illuminate the sample with narrow-band wavelength light sources. As each discrete wavelength illuminates the sample a 2D image is acquired using a camera with a uniform wavelength response.…”

“…near IR images of fats and lipids in biological samples), [2] Imaging physico-chemical processes that modify rather than simply reflect light (most often fluorescence) [3] Identifying different metamers -materials that look the same in a RGB image but in fact have different reflectance spectra. Colours that match this way are called metamers.…”

Multiple Immunoenzyme Staining: Methods and Visualizations for the Observation With Spectral Imaging

“…Papers describing spectral imaging of bright field tissue samples are rare (Ornberg et al 1999;Ornberg 2001;Levenson and Mansfield 2006). On introduction of spectral imaging of bright field microscopical specimens, the whole concept of contrasting basic colors and mixed color is drastically changed.…”

Get closer!—Into the path lab, into the OR, (in)to the patient

“…Moreover, solid-phase assays open the chance to analyze this process even in vivo and in 5D: space, time, and function. It is of highest interest to increase the number of assays available for detailed functional analyses in vivo for human applications as they have been described for animal studies and to design appropriate instruments to be taken (in)to the patient (13)(14)(15)(16)(17) …”