Infra-red Thermal Imaging of the Inner Canthus: Correlates with the Temperature of the Injured Human Brain

Abstract

Introduction: Infra-red (IR) thermometry is a safe and valid method to determine internal and surface temperature in human subjects. Under conditions of brain damage (head injury or stroke) knowledge of changes in the temperature of intracranial tissue is justified because of the vulnerability of neurons to accelerated damage at temperatures at the upper end of the febrile range. Aim: To determine the temperature at the inner canthus (IC) of the eye as a potential surrogate for brain temperature. Methods: Invasive monitoring of deep brain structures, lateral ventricle and deep white matter. IR temperature readings obtained at right and left IC. Results: Strong correlations were evident between R and L IC and brain. Close, as well as poor, agreement between sites was shown in some patients and at some times. For right hemispheric lesions four had a better correlation between TbrV and TRIC when compared to TLIC. When the correlation between TbrV and TLIC was better compared to TbrV and TRIC, four had a predominant right hemispheric lesion. Conclusions: Improved techniques for IR thermal imaging accuracy at the bedside has the potential to improve temperature measurement agreement. The predominant lesion side may have a bearing on maximum ipsilateral IC temperature Further studies are ongoing in this pilot study population.

Infrared Imaging of the Brain-Eyelid Thermal Tunnel: A Promising Method for Measuring Body Temperature in Afebrile Children

“…The camera's emissivity was set to ε = 0.95 to accurately measure the temperature of the inner canthus of the radiant eyelid (T ic,eye ) on both sides (Figure 1), considering that the thinner skin, with a high-k thermal conductivity (k = 0.00009 Kcal/(s•N•C)) and lower fat content in this area [9], typically results in an emissivity value closer to 0.95. All images were taken with the camera at a minimum focus distance of 0.3 meters (0.984 feet) in the multispectral mode.…”

“…the thinner skin, with a high-k thermal conductivity (k = 0.00009 Kcal/(s•N•C)) and lower fat content in this area [9], typically results in an emissivity value closer to 0.95. All images were taken with the camera at a minimum focus distance of 0.3 meters (0.984 feet) in the multispectral mode.…”

“…The angular artery, which has three branches, originates from the ophthalmic artery (specifically the supratrochlear branch), and is located directly beneath the skin of the inner canthus. Because of the abundant vascular supply and consequent blood perfusion in this area, it has the potential to be a useful location for estimating core temperature [7][8][9].…”

Bilateral assessment of body core temperature through axillar, tympanic and inner canthi thermometers in a young population

“…A piece of research, aiming to verify if the temperature obtained with IRT imaging at the IC of the eye was related to brain temperature taken invasively (Childs et al 2012), found strong correlations between the temperatures of both sites, the IC of the eye and of the brain. It also showed that in patients with a lesion in one side of the brain, that the corresponding side had elevated temperature at the respective IC of the eye.…”