Ricardo Vardasca

Current Issues in Medical Thermography

Digital Medical Thermal Imaging (DMTI) is a modality of medical imaging for monitoring the surface of the skin temperature. The technology evolution over the last 50 years contributed for more accuracy in the measurements and to significantly decrease the size of the equipment making them portable today. The applications of this technique in medicine are on the peripheral vascular, neurological and musculoskeletal conditions assessing and monitoring, in such areas like: cardiology, chronic diseases, dermatology, dentistry, obstetrics, occupational medicine, oncology, physiotherapy, public health, surgery and veterinary medicine. In this chapter the technique is introduced, with its historical perspective, the fundamental physics, the human physiology concepts, the equipment characterization, the existing proposals for examination protocols, the used image processing techniques, the latest developments and applications and the current limitations and challenges.

Comparison of boundary detection techniques to improve image analysis in medical thermography

Abstract In digital imaging, poor contrast between the target and its background can affect the extraction of the object of interest and increase the time used in its analysis. Medical thermal imaging requires the correct interpretation of the thermal values obtained from the region of interest. In this investigation, a subjective and objective comparison of currently available outlining techniques is performed to determine the optimal method. Results indicate that probability-based operators produce the best outcome especially after pre-processing with a noise removal filter. The findings of this study suggest that probability-based edge detection techniques in combination with homomorphic filtering and limited post-processing provide initial estimate delineations of areas. These delineations are of sufficient quality for subsequent automatic or semiautomatic post-processing so that a maximum of the original information inside the regions is preserved without loss or distortion of data.

Thermographic characterization of masticatory muscle regions in volunteers with and without myogenous temporomandibular disorder: preliminary results

OBJECTIVES This study aims to conduct a non-invasive measurement of the cutaneous temperature of selected masticatory muscle regions of volunteers with and without myogenous temporomandibular disorder (TMD), using infrared thermography. METHODS 23 females (10 myogenous TMD volunteers and 13 controls) were recruited and studied. The temperature at the surface of the facial area over the anterior temporalis and masseter muscles was assessed by medical thermography, using regional lateral views and clinical examination. RESULTS The temperature levels measured at the masseter and anterior temporalis muscle regions in myogenous TMD volunteers (32.85 ± 0.85 and 34.37 ± 0.64 ºC, respectively) were significantly lower (p < 0.05) than those measured in controls (33.49 ± 0.92 and 34.78 ± 0.44 ºC, respectively). Medical infrared imaging indicated a mean difference of 1.4 ºC between the masseter and anterior temporalis regions. Analysis of the comparison between the absolute and normalized mean temperatures was performed using the pairwise comparison of receiver operating characteristic curves, and no statistically significant difference was observed (p > 0.05). The sensitivity and specificity of the thermographic assessment for the masseter region was of 70% and 73%, respectively and for the anterior temporalis region was of 80% and 62%, respectively. CONCLUSIONS This method of evaluating masticatory muscle regions of this preliminary study seems to indicate that it can be used as an aid in complimentary diagnosing of TMDs.

NEW STANDARDS FOR FEVER SCREENING WITH THERMAL IMAGING SYSTEMS

Infrared thermal imaging has in recent years become more accessible and affordable as a means of remote sensing for human body temperature such as in identifying a person with fever. The implementation and operational guidelines for identifying a febrile human using a screening thermograph as documented in the ISO/TR 13154:2009 ISO/TR 80600 has been deployed for the screening of a total of 402 children. It was found that there was a significant difference between the temperatures measured in non-fevered patients and those with known fever, with the thermal imaging of the eye region being the most rapid non-contact site for measurement.

Towards a detailed anthropometric body characterization using the Microsoft Kinect.

Anthropometry has been widely used in different fields, providing relevant information for medicine, ergonomics and biometric applications. However, the existent solutions present marked disadvantages, reducing the employment of this type of evaluation. Studies have been conducted in order to easily determine anthropometric measures considering data provided by low-cost sensors, such as the Microsoft Kinect. In this work, a methodology is proposed and implemented for estimating anthropometric measures considering the information acquired with this sensor. The measures obtained with this method were compared with the ones from a validation system, Qualisys. Comparing the relative errors determined with state-of-art references, for some of the estimated measures, lower errors were verified and a more complete characterization of the whole body structure was achieved.

The effect of different vibration frequencies in the skin temperature in healthy subjects

This study assessed the impact of acute exposure to whole-body vibration in skin temperature of the lower limbs in healthy subjects. Twelve healthy volunteers (mean age 24.55 years) were randomly assigned to two groups and were exposed to different whole-body vibration protocols (35 Hz and 40 Hz frequency and 5-6 mm amplitude). Skin temperature was measured before and immediately after exposure. Infrared thermography measurements revealed that skin temperature decreased significantly after exposure to vibration. The results were different for both vibration frequencies. Exposure to 35 Hz vibration produced significant decreases in skin temperature in some of the studied regions of interest and exposure to 40 Hz vibration produced significant decreases in skin temperature in all studied regions of interest.

The facial thermal effect of dynamic mechanical and vascular provocation tests: Preliminary study

Anatomical and functional information of the structures of interest is the basis of radiology interpretation. Many diagnosis of some facial diseases may be done through medical imaging techniques, however the most conventional present lack of information in analyzing physiological functional aspects such as microcirculation and autonomous nervous system. This study aims to evaluate and compare 2 techniques of dynamic infrared thermography (chewing and vibration tests associated with thermal test) in 3 skin facial regions of volunteers with and without temporomandibular disorder (DMT). Sixty-four participants (24 symptomatic and 40 asymptomatic) were included. The surface temperature over trochlear, supraorbital and facial arteries and veins was assessed by medical thermography, using regional frontal views and clinical examination. Results show that the cutaneous temperature over the ROIs does not change in the presence of DMT. The functional tests did not have statistical evidence of independence (p>0.05). This preliminary assessment was made only in front views. A future evaluation of lateral thermal imaging is advised because it can provide important and new pathophysiological information in the characterization for DMT subjects and healthy individuals.

Skin Temperature in Diabetic Foot Patients: A Study Focusing on the Angiosome Concept

The effect of peripheral artery disease in the skin temperature of diabetic foot patients is not known. In this study, skin temperature was assessed in patients with established diagnosis of diabetic foot, all with neuropathy, with or without peripheral artery disease. Thermograms of feet with neuropathy and peripheral vascular disease were compared with thermograms of feet with neuropathy, without peripheral artery disease. Skin temperature was lower in feet with neuropathy and peripheral artery disease and differences were statistically significant (p < 0.05) in most regions of interest.

Building Low Cost Cloud Computing Systems

The actual models of cloud computing are based in megalomaniac hardware solutions, being its implementation and maintenance unaffordable to the majority of service providers. The use of jail services is an alternative to current models of cloud computing based on virtualization. Models based in utilization of jail environments instead of the used virtualization systems will provide huge gains in terms of optimization of hardware resources at computation level and in terms of storage and energy consumption. In this paper it will be addressed the practical implementation of jail environments in real scenarios, which allows the visualization of areas where its application will be relevant and will make inevitable the redefinition of the models that are currently defined for cloud computing. In addition it will bring new opportunities in the development of support features for jail environments in the majority of operating systems. Keywords—cloud computing; IAAS; jail environments; optimization; PAAS.

Handgrip Evaluation: Endurance and Handedness Dominance

This work contributes to the development of a repeatable and objective methodology for relating the physiological energy spent during a handgrip exercise, identified through the variation of skin temperature, with the average grip force, and evaluate its influence on exercise endurance and handedness dominance. For that purpose, a special handgrip dynamometer is used as well as an Infrared Thermal Imaging (IRT) to map large areas of skin surface temperature. Results suggest that at least a 10-grips test with the dynamometer is required to produce reliable thermal results and the dominant hand should be used. In the future, relationship between the thermal variables and mechanical work involved during the handgrip should be addressed. The developed methodology should be applied to populations at health risk conditions to which the use of the handgrip dynamometer can provide information for diagnose and treatment assessment.