High-resolution FTIR imaging of colon tissues for elucidation of individual cellular and histopathological features

Abstract

a Novel technologies that could complement current histopathology based cancer diagnostic methods are under examination. In this endeavour mid-infrared spectroscopic imaging is a promising candidate that can provide valuable bio-molecular information from unstained cells and tissues in a rapid and a nondestructive manner. With this imaging technique, the biochemical information obtained from smaller areas of the tissues can be of clinical significance and hence the measured pixel size. Until recently it was difficult to obtain spectral data from pixels below around 5 microns square. High NA objectives have been utilised to reduce the ideal diffraction limit, enabling for the first time elucidation of subcellular features.In this context, the ability of high-resolution imaging, obtained using novel high-magnification optics retro-fitted onto a bench top FTIR imaging system, to characterise histopathological features in colonic tissues has been tested. Formalin fixed paraffin embedded colon tissues from three different pathologies were imaged directly using the conventional and the high-magnification imaging set-ups. To circumvent chemical de-paraffinization protocols, an extended multiplicative signal correction (EMSC) based electronic de-paraffinization was carried out on all the infrared images. Multivariate analysis of the highmagnification infrared imaging data showed a detailed information of the histological features of the colon tissue in comparison to conventional imaging. Furthermore, high-magnification imaging has enabled a label-free characterization of the mucin rich goblet cell features in an unprecedented manner.The current study demonstrates the applicability of high-magnification FTIR imaging to characterise complex tissues on a smaller scale that could be of clinical significance.

Raman spectroscopic imaging for quantification of depth-dependent and local heterogeneities in native and engineered cartilage

“… 32 , 33 Consequently, histochemical staining is conventionally viewed as a qualitative assessment tool for cartilage ECM distribution analysis. While more robust analytical techniques for cartilage ECM measurements have recently emerged, such as Fourier transform infrared spectroscopy imaging, they are also associated with critical limitations, such as a low spatial resolution (~5 μm 34 ) and a lack of compatibility with unfixed, hydrated tissue specimens. As such, Raman spectroscopic imaging possesses considerable benefits above prior tissue characterization techniques, including quantitative accuracy, diffraction limited spatial resolution, and compatibility with hydrated tissue specimens.…”

Fourier Transform Infrared Microscopy Enables Guidance of Automated Mass Spectrometry Imaging to Predefined Tissue Morphologies

“…FTIR imaging uses commercially available instruments and has the ability to record general biomolecular characteristics of an unstained tissue (e.g. vibrational spectroscopic bands characteristic of lipids, proteins or nucleic acids) in a rapid, label-free and non-destructive manner 18 , 19 . The technique has gained recognition as a diagnostic tool revealing disease-related structural and compositional features in various cancer types and other diseases such as diabetes mellitus 20 – 25 .…”

Identification of gastrointestinal cancers using rapid mid-IR spectral imaging

“…Nonetheless, the high-magnification imaging showed detailed histological aspects of colonic glands, and could resolve smaller cellular features (such as the goblet cells) directly. 2,7 In summary, we have highlighted the potential benefits of high-magnification IR imaging for visualization of the biochemical distribution across colonic tissue sections. There appears to be some improvement in performance for two-group discrimination of disease using higher magnification optics with 1.1 m pixels.…”