Optical coherence tomography (OCT) has been used as part of a ground breaking translational study to shed some light
on one of the worlds most prevalent autoimmune diseases; psoriasis. The work successfully integrates the fields of
optical imaging, biochemistry and dermatology in conducting a dermal microdialysis (DMD) trial for quantitative
histamine assessment amongst a group of psoriasis sufferers. The DMD process involves temporary insertion of
microscopic hollow tubes into a layer of skin to measure the levels of histamine and other important biological molecules
in psoriasis. For comparison purposes, DMD catheters were implanted into healthy, peri-lesional and lesional skin
regions. The catheters' entry and exit points and their precise locations in the epidermal layer of the skin were confirmed
using OCT thus obtaining high resolution, wide-field images of the affected skin as well as catheter placement whilst
local microdialysis enabled a tissue chemistry profile to be obtained from these three skin regions including histamine, a
local immune system activator known to contribute towards itch and inflammation. Together these tools offer a
synergistic approach in the clinical assessment of the disease. In addition, OCT delivered a non-invasive and rapid
method for analyzing the affected skin architecture.
The use of microneedles as a method of circumventing the barrier properties of the stratum corneum is receiving much attention. Although skin disruption technologies and subsequent transdermal diffusion rates are being extensively studied, no accurate data on depth and closure kinetics of microneedle-induced skin pores are available, primarily due to the cumbersome techniques currently required for skin analysis. We report on the first use of optical coherence tomography technology to image microneedle penetration in real time and in vivo. We show that optical coherence tomography (OCT) can be used to painlessly measure stratum corneum and epidermis thickness, as well as microneedle penetration depth after microneedle insertion. Since OCT is a real-time, in-vivo, nondestructive technique, we also analyze skin healing characteristics and present quantitative data on micropore closure rate. Two locations (the volar forearm and dorsal aspect of the fingertip) have been assessed as suitable candidates for microneedle administration. The results illustrate the applicability of OCT analysis as a tool for microneedle-related skin characterization.
Since its discovery in 1842 by Christian Johann Doppler, the Doppler Effect has had many applications in the scientific
world. In recent years, the phenomenon has been integrated with Optical Coherence Tomography (OCT) yielding
Doppler Optical Coherence Tomography (DOCT), a technique that is useful for high-resolution imaging of the skin
microcirculation. However, interpretation of DOCT images is rather challenging. Thus, our study aims to aid
understanding of DOCT images with respect to parameters of microcirculation components such as blood vessel size,
depth and angular position. To this end, we have constructed a gel-based tissue and blood-flow model for performing
DOCT studies under well controlled conditions. We present results from a pilot study using a gel-based tissue and blood
flow model. Human blood was pumped through the model at various velocities from a commercial calibrated syringe
pump, serving as a standard reference point for all velocity measurements. The range of velocity values was chosen to
coincide with that found in the human vasculature. Simultaneous DOCT imaging at different flow rates contributed to
establishing the capabilities and limitations of the DOCT system under investigation. We present preliminary results as
first step to developing a robust validation protocol with which to aid future research in this area.
This report outlines results from an independent study assessing the clinical potential of an emerging, contemporary
imaging technology. Tissue Viability (TiVi) imaging is an easily implemented, non-invasive, and portable technique
which maps the blood circulation in the surface dermal layer. However, its routine clinical implementation awaits the
development of the necessary standardised protocols. Thus the pilot study examines the efficacy of a novel TiVi imaging
device within a localised skin blood flow occlusion protocol. The test was administered to the upper volar forearm of 19
healthy subjects (10:9 Female:Male) for 5 different time periods ranging from 5 to 25 seconds. Dermal areas
corresponding to 100 × 100 pixels (2.89 cm2) were monitored for 60 seconds prior to, during and after each occlusal test.
Our results support the relevance of a TiVi occlusion protocol for physiological assessment of the skin microcirculation.
The quantitative analysis of illicit materials using Raman spectroscopy is of widespread interest for law enforcement and healthcare applications. One of the difficulties faced when analysing illicit mixtures is the fact that the narcotic can be mixed with many different cutting agents. This obviously complicates the development of quantitative analytical methods. In this work we demonstrate some preliminary efforts to try and account for the wide variety of potential cutting agents, by discrimination between the target substance and a wide range of excipients. Near-infrared Raman spectroscopy (785 nm excitation) was employed to analyse 217 samples, a number of them consisting of a target analyte (acetaminophen) mixed with excipients of different concentrations by weight. The excipients used were sugars (maltose, glucose, lactose, sorbitol), inorganic materials (talcum powder, sodium bicarbonate, magnesium sulphate), and food products (caffeine, flour). The spectral data collected was subjected to a number of pre-treatment statistical methods including first derivative and normalisation transformations, to make the data more suitable for analysis. Various methods were then used to discriminate the target analytes, these included Principal Component Analysis (PCA), Principal Component Regression (PCR) and Support Vector Machines.
Conference Committee Involvement (3)
14th International Machine Vision and Image Processing Conference
10 October 2010 |
3rd Biophotonics and Imaging Graduate Summer School (BIGSS 10)
27 August 2010 |
2nd Biophotonics and Imaging Graduate Summer School (BIGSS 09)
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