Forensic visualization of foreign matter in human tissue by near‐infrared spectral imaging: Methodology and data mining strategies

Abstract

Background:Rapidity of data acquisition, high image fidelity and large field of view are of tremendous value when looking for chemical contaminants or for the proverbial “needle in the haystack” – in this case foreign inclusions in histologic sections of biopsy or autopsy tissues. Near infrared chemical imaging is one of three chemical imaging techniques (NIR, MIR and Raman) based on vibrational spectroscopy, and provides distinct technical advantages for this application.Methods:We have chosen to utilize and evaluate near infrared (NIR) imaging for studies of foreign materials in tissue because the experimental configuration is relatively simple, data collection is rapid, and large sample areas can be screened with high image fidelity and spatial resolution.Results:We have shown that NIR imaging can readily find and identify silicone gel inclusions in biological tissue samples. Additionally, preliminary results indicate that spectral signatures in the data set are also potentially sensitive to structural changes in the surrounding tissue that may be induced by the foreign body.Conclusions:NIR chemical imaging is a powerful, non‐destructive tool for localization and identifying foreign contaminants in biological tissue. Preliminary results indicate that NIR imaging is also sensitive enough to differentiate tissue types (perhaps based on collagen structural differences), and provide data on the spatial localization of these components. © 2006 International Society for Analytical Cytology

Forensic Analysis of Human Autopsy Tissue for the Presence of Polydimethylsiloxane (Silicone) and Volatile Cyclic Siloxanes using Macro FT‐IR, FT‐IR Spectroscopic Imaging and Headspace GC‐MS

“…These limitations have been mitigated with the use of mid‐infrared spectroscopic mapping and/or imaging instruments , which provide the ability to collect an infrared spectrum at each discrete location. Although PDMS inclusions have been investigated using near‐infrared spectroscopic imaging , this technique may not necessarily be considered PDMS specific. The result of the FT‐IR imaging approach is a three‐dimensional “data cube” with two dimensions of spatial information and one dimension of chemical (molecular) information, which can be examined for the presence of targeted and untargeted compounds using a host of available data reduction software packages.…”

Microfluidic impedance‐based flow cytometry

“…Technologies on the horizon include Raman spectroscopy, impedance cytometry, near infrared spectroscopy, and photoacoustic cytometry (18)(19)(20)(21)(22)(23). Newly developed or modified instrumentation for optical imaging based on reflectance, two-photon, and multispectral imaging can detect and localize cellular signatures of cancer in vivo, without the use of contrast agents or extrinsic dyes (24).…”

PryJector: A Device for In Situ Visualization of Chemical and Physical Property Distributions on Surfaces Using Projection and Hyperspectral Imaging*,†

“…Detection of explosive residues in fingerprints was also demonstrated in Emmons et al (24) using Raman chemical imaging. Examples of other forensic applications using chemical image analysis are classification of man‐made bicomponent fibers (25), document analysis where spectra were used to determine the sequence of intersecting lines produced by ballpoint pens and laser printers (26), analysis of paints, inks, and firearm propellants (27) in the UV–Vis–NIR and IR regions, the detection of mass graves using remote sensing (airborne and satellite imagery) in the UV–Vis–NIR range (28), the use of Raman imaging to detect different types of condom lubricant compounds (29), and the detection and visualization of foreign matter in human tissue (30) using near‐infrared chemical imaging. In addition, the application of chemical imaging techniques such as time‐of‐flight secondary ion mass spectrometry has also been reported in the literature, here for detecting various bioagents (31).…”

“…Over the last 10 years, there has been a significant increase in the number of articles published using chemical imaging for forensic purposes. A majority of these contributions have been in the area of fingerprint detection (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32). In most of these cases, chemical imaging has been used to enhance weak and borderline fingerprints already treated with traditional methods, such as ninhydrin and cyanoacrylate.…”