Infrared imaging or thermography is a non-invasive tool which uses an infra-red camera. This modality is capable of detecting infrared radiation from the skin surface that related to the temperature of the body or body region. The information can be used to detect areas of relative hot and cold. These temperature differences may relate to underlying vascular or metabolic changes, such as those caused by inflammation of joints, trauma to muscle or neurological dysfunction.
Before one can use this modality in research or clinical studies, the following conditions need to be met:
the IR camera should be calibrated using traceable standards
the methodology should be standardised
there should be a good understanding of the variations found in the healthy / asymptomatic population.
Our research has concentrated on the last two points.
We have collaborated in a study to generate an atlas of standard thermographic images (Jones, Plassman, Ammer & Ring).
Studied potential effects of somatotype, age, sex and levels of activity. Somatotype appears to affect the absolute surface temperature and potentially obscures vascular changes in some deeper musculature. One general finding is that a symmetry of image (left to right) appears the norm in healthy individuals.
!http://chiropractic.research.glam.ac.uk/media/files/photos/back_thermographs_obese_over_non_obese_males.jpg!(Infrared images of 2 individuals (dorsal torso) with differing somatotype. The upper image is of a slightly endomorphic male whereas the lower image is of an meso-ectomorphic male. Scale bars indicate the relative temperature for each colour shown)
We are also studying the relationship between neuro/vascular illnesses and the thermographic image. Preliminary data suggests that chronic conditions such as Fibromyalgia and CRPS-1 can show a relationship between the extent of the disease and the presentation of thermographic changes.
A further area of endeavour is an attempt tostandardise the testing and vascular effects of vibration on those with Conditions such as Hand Arm Vibration Syndrome (HAVS) / Vibration White Finger (VWF). The characteristic tendency towards peripheral vascular shutdown in these conditions makes the changes amenable to quantification by thermography. We have designed and are testing a device which creates a more authentic stimulation (than previously published methods) and are combining this with IR thermographic visualisation and analysis.
(The image shows the dorsal surface of the hands as seen using an infrared imaging system. Please note the brighter areas denote slightly higher temperatures related to vascular structures. See scale bar on the right for detail.)
Heusch AI. McCarthy PW. Thermography in chiropractic. European Journal of Chiropractic. 2003; 49(3): 281-7.
Heusch AI. McCarthy PW. Somatotype and infrared thermographic imaging. Thermology International. Vol. 14(2)(pp 51-56), 2004
McCarthy PW & Heusch AI (2006) diagnostic device: an authentic stimulation device and objective assessment tool for detecting presence of vibration related neurovascular conditions of the hand and arm. BRITISH PATENT FILING No. 0516067. EUROPEAN PATENT APPLIED FOR. Patent