Thermal and Spectral Imaging in a Clinical Environment

There is growing clinical interest in non-invasive techniques to diagnose disease – these include breath analysis, cardiovascular and imaging. The latter consisting of both Thermal infrared (TIR) imaging where the distribution of body heat at the skin can be measured, and spectral imaging where pigments within the skin can be detected. Recent developments in imaging technology are allowing both TIR and spectral imagers to achieve good spatial resolution. Such techniques have been implemented at the Leicester Royal Infirmary (LRI) within the Diagnostics Development Unit (DDU). The majority of studies to date using these techniques have used a controlled laboratory environment. In this work the utility and practicality of both TIR imaging and hyperspectral imaging in a real clinical environment were investigated. Based upon previous work appropriate measurement and calibration protocols were developed. The clinical utility of using the available DDU imagers and protocols was investigated via ethically approved TIR studies of fever and sepsis patients and hyperspectral studies of kidney, liver and skin lesions patients. This work was conducted in the Accident and Emergency Department at the LRI and other appropriate clinical units within the University Hospitals of Leicester NHS trust. TIR imaging studies of fever, sepsis patients showed an ability to detect significant temperature abnormalities both in terms of actual values and also in terms of their spatial distribution. This includes detection of mottling pattern which may be diagnostic of progression towards sepsis. Hyperspectral imaging showed some signatures associated with liver disease, particularly within the sclera of the eye. The possible confounding effect of tanning in hyperspectral imaging of the skin was investigated. It is clear that further development is required for practical utilisation of the hyperspectral technique within the clinical environment. The main output of this work has been to develop protocols for use of the two techniques.