Comparison of Three Thermal Cameras with Canine Hip Area Thermographic Images

Abstract

ABSTRACT. The objective of this study was to compare the method of thermography by using three different resolution thermal cameras and basic software for thermographic images, separating the two persons taking the thermographic images (thermographers) from the three persons interpreting the thermographic images (interpreters). This was accomplished by studying the repeatability between thermographers and interpreters. Forty-nine client-owned dogs of 26 breeds were enrolled in the study. The thermal cameras used were of different resolutions-80 × 80, 180 × 180 and 320 × 240 pixels. Two trained thermographers took thermographic images of the hip area in all dogs using all three cameras. A total of six thermographic images per dog were taken. The thermographic images were analyzed using appropriate computer software, FLIR QuickReport 2.1. Three trained interpreters independently evaluated the mean temperatures of hip joint areas of the six thermographic images for each dog. The repeatability between thermographers was >0.975 with the two higherresolution cameras and 0.927 with the lowest resolution camera. The repeatability between interpreters was >0.97 with each camera. Thus, the between-interpreter variation was small. The repeatability between thermographers and interpreters was considered high enough to encourage further studies with thermographic imaging in dogs. Thermography (also known as infrared thermography and infrared imaging) is a noninvasive and safe method of detecting changes in superficial temperature in animals [15,16,23,28] and humans [20,26]. A change in superficial temperature may be an indicator of several illnesses and pain [10,13]. Although this method could be useful as a diagnostic tool in everyday veterinary medicine, its clinical utility has rarely been studied, especially in small animals. In recent years, the technology of the cameras has improved, prices have gone down and the equipment has become easy to transport, which makes bedside use feasible.The normal temperature of an area of the body is a product of cell metabolism and local blood flow [9]. Inflammation in subcutaneous and deeper tissues can be reflected by superficial tissue temperature changes of ≥1°C. In the inflammatory process, skin temperature rises due to changes in the diameter of blood vessels and the rate of blood flow as well as increased capillary permeability, which can be seen with thermography [29,30]. The human hand and fingers can detect a ≥2°C difference in temperature on a patient's skin [11], whereas modern infrared cameras have been claimed to be more than 10 times more sensitive in detecting temperature changes. Thermography can be used to detect changes in peripheral blood flow from the resulting changes in heat loss [25].The objective of this study was to compare three different resolution thermal cameras in investigating the amount of variance caused by thermographers and interpreters of thermal camera images (thermographic images). In addition, we visually observed the appearance of varying hair c...

Thermographic images from healthy knees between dogs with long and short hair

“…Long-haired dogs show minimal temperature loss by convection, so, the coat acts as an insulator, preventing dissipation of infrared radiation from the body. This justifies the findings from the present study and has been recognized and discussed by several authors (EDDY et al 2001;TUNLEY & HENSON, 2004;LOUGHIN & MARINO, 2007;INFERNUSO et al 2010;VAINIONPÄÄ et al 2012) and observed in multiple species, such as horses, llamas, and dogs. However, despite this influence being recognized by most authors, there has no comparative study quantifying the findings.…”

“…In addition to the thermal insulation, it also caused difficulties in marking areas of interest due to loss of anatomical references. Similarly, a previous study (VAINIONPÄÄ et al 2012) noted that the hair length and type can compromise the examination due to the loss of anatomic references to define the areas evaluated. Thermographic cameras that capture photographs simultaneously as the thermal image, as done in this study, help to identify anatomical references.…”

“…According to the authors Infernuso et al (2010), capturing the images also requires a standard because images captured from different angles can confuse the readings by the software. Still, problems occur when analyzing the software images of animals with long and curly hair because the software programs do not recognize the real limits of the areas due to false volume caused by the coat (VAINIONPÄÄ et al 2012). Indeed, the thermographic images can be easily manipulated in the absence of an extremely rigid method, leading to misinterpretation of the automated analysis of these images.…”

“…In addition to thermal imaging, the test quantifies information in real-time and detects very small temperature variations of up to 0.07ºC in less than 0.03 sec (BRIOSCHI et al 2007). Nomura et al Thermography, as per any diagnostic method, requires minimum standardization before its use (VAINIONPÄÄ et al 2012). Consideration of the environment, such as temperature, humidity, solar radiation and convective air movement is required.…”

Evaluation of Thermographic Imaging in Canine Hindlimb Muscles After 6 Min of Walking—A Pilot Study

“…There are several studies on the use of thermal imaging in canines. The ability to obtain consistent thermographic images in healthy dogs has been demonstrated (12,13). Thermal imaging has been shown to be useful in detection of several pathological conditions in dogs including osteosarcoma (14), elbow dysplasia (15), cranial cruciate ligament rupture (16,17), and intervertebral disc disease (18).…”