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Dynamic Thermal Imaging for Intraoperative Monitoring of Neuronal Activity and Cortical PerfusionHoffmann, Nico 23 November 2017 (has links) (PDF)
Neurosurgery is a demanding medical discipline that requires a complex interplay of several neuroimaging techniques. This allows structural as well as functional information to be recovered and then visualized to the surgeon. In the case of tumor resections this approach allows more fine-grained differentiation of healthy and pathological tissue which positively influences the postoperative outcome as well as the patient's quality of life.
In this work, we will discuss several approaches to establish thermal imaging as a novel neuroimaging technique to primarily visualize neural activity and perfusion state in case of ischaemic stroke. Both applications require novel methods for data-preprocessing, visualization, pattern recognition as well as regression analysis of intraoperative thermal imaging.
Online multimodal integration of preoperative and intraoperative data is accomplished by a 2D-3D image registration and image fusion framework with an average accuracy of 2.46 mm. In navigated surgeries, the proposed framework generally provides all necessary tools to project intraoperative 2D imaging data onto preoperative 3D volumetric datasets like 3D MR or CT imaging. Additionally, a fast machine learning framework for the recognition of cortical NaCl rinsings will be discussed throughout this thesis. Hereby, the standardized quantification of tissue perfusion by means of an approximated heating model can be achieved. Classifying the parameters of these models yields a map of connected areas, for which we have shown that these areas correlate with the demarcation caused by an ischaemic stroke segmented in postoperative CT datasets.
Finally, a semiparametric regression model has been developed for intraoperative neural activity monitoring of the somatosensory cortex by somatosensory evoked potentials. These results were correlated with neural activity of optical imaging. We found that thermal imaging yields comparable results, yet doesn't share the limitations of optical imaging. In this thesis we would like to emphasize that thermal imaging depicts a novel and valid tool for both intraoperative functional and structural neuroimaging.
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Dynamic Thermal Imaging for Intraoperative Monitoring of Neuronal Activity and Cortical PerfusionHoffmann, Nico 09 December 2016 (has links)
Neurosurgery is a demanding medical discipline that requires a complex interplay of several neuroimaging techniques. This allows structural as well as functional information to be recovered and then visualized to the surgeon. In the case of tumor resections this approach allows more fine-grained differentiation of healthy and pathological tissue which positively influences the postoperative outcome as well as the patient's quality of life.
In this work, we will discuss several approaches to establish thermal imaging as a novel neuroimaging technique to primarily visualize neural activity and perfusion state in case of ischaemic stroke. Both applications require novel methods for data-preprocessing, visualization, pattern recognition as well as regression analysis of intraoperative thermal imaging.
Online multimodal integration of preoperative and intraoperative data is accomplished by a 2D-3D image registration and image fusion framework with an average accuracy of 2.46 mm. In navigated surgeries, the proposed framework generally provides all necessary tools to project intraoperative 2D imaging data onto preoperative 3D volumetric datasets like 3D MR or CT imaging. Additionally, a fast machine learning framework for the recognition of cortical NaCl rinsings will be discussed throughout this thesis. Hereby, the standardized quantification of tissue perfusion by means of an approximated heating model can be achieved. Classifying the parameters of these models yields a map of connected areas, for which we have shown that these areas correlate with the demarcation caused by an ischaemic stroke segmented in postoperative CT datasets.
Finally, a semiparametric regression model has been developed for intraoperative neural activity monitoring of the somatosensory cortex by somatosensory evoked potentials. These results were correlated with neural activity of optical imaging. We found that thermal imaging yields comparable results, yet doesn't share the limitations of optical imaging. In this thesis we would like to emphasize that thermal imaging depicts a novel and valid tool for both intraoperative functional and structural neuroimaging.
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LINE SCANNING THERMOGRAPHY FOR DETECTION OF RAIL BASE AND INTERNAL DEFECTS: A FEASIBILITY STUDYWinn, Jackson 01 December 2022 (has links)
The railroad industry is pivotal in the United States to ensure that the supply chain does not shut down for the American people. Non-Destruction Evaluation (NDE) approaches are preferred and performed on the railways to ensure the safety of the population that is exposed to the railway industry. When damage occurs on the rail base, there is an increased risk derailment of the train cars. Due to the nature of the railroad industry, there are challenges with developing a quick and reliable inspection method, along with the improvement of current NDE methods. The load, speed, and cycles of trains have increased the load that track sections endure over time. Some railways that were originally built in the early 20th century are still utilized today, designed for trains that are not nearly as heavy or fast as used today. Defects and damage on the railways lead to the need of development of an NDE approach utilizing Line Scan Thermography approaches. One of the most common defects that are formed are on the rail base is known as “base nicks” and “half-moon cracks”, these types of defects can occur over time. This research aims to study the feasibility of applying this NDE technique to detect defects that can occur on a rail base, both internal and external. For this research, a heat source up to 6000 W and tested velocities up to 447.1 mm/s (1.0 mph) are used to study the effects of line scanning thermography on various samples. In total, 10 samples are employed to test for feasibility: each one having a unique set of defects. Some defects fabricated on these samples are internal, such as bottom drilled holes (BDH) and side drilled holes (SDH); some of these samples are fabricated from actual rail samples. From tests conducted for internal defects, it can be concluded that defects with diameters of 6.35 mm (0.25”) can be detected at a remaining thickness from the observation surface of 6.35 mm. Along with internal defects, there are also external defects employed on the samples; these defects include simulated base nicks, fractures, and half-moon cracks. For surface defects tests from this research, it is found that the anomalies can be detected visually. The results from the experimental studies provide insight and limitations of LST for the possibility of a future commercial application.
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Bezkontaktní termografické vyšetření v klinické medicíně / Contactless thermography in clinic medicineLangerová, Jana January 2017 (has links)
This thesis deals with the theory of infrared thermography in medicine and its subsequent practical application in the creation of the program. As part of this diploma thesis, researches were carried out on the topic of thermovision imaging techniques, its use mainly in clinical medicine and also research in the field of image data processing. Theoretical knowledge is written into the first three chapters of this thesis. The next chapter deals with the design of a web application for the analysis of thermographic images of patients with vascular disease lower limbs and the PHP program environment with its particulars. In the second half of the thesis there is a detailed description of the practical creation of the mentioned application in PHP environment with the use of some PHP libraries. One chapter is also devoted to the discussion of the method of obtaining thermographic images for testing the created application and to the statistical evaluation of acquired data. This thesis is divided into 8 different chapters and also into many sub-chapters.
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The use of thermography in clinical Thoracolumbar disease in DachshundsSargent, Gerald R. January 1900 (has links)
Master of Science / Department of Clinical Sciences / James K. Roush / Objective – To evaluate the value of thermography in a clinical setting for dogs with thoracolumbar disease.
Animal Population – Thirteen client-owned short-haired Dachshunds presented to Kansas State University Veterinary Medical Teaching Hospital for paraparesis/paraplegia and diagnosed with thoracolumbar disease via myelogram/CT and confirmed during surgical decompression.
Procedures - Thermal images were obtained with a hand-held infrared camera with a focal plane array uncooled microbolometer. Images were obtained after physical exam and client consultation and prior to any pre-anesthetic medications, approximately 30+ minutes after entering the hospital. Additional images were obtained in the same manner at 24 hour intervals following surgery until discharge. Six regions of interest (ROI) were identified and recorded. The ROIs identified were right and left thoracic, lumbar and pelvic regions. From each of these regions average temperatures were taken.
Results - Temperatures in the pelvic region were significantly cooler (p< 0.001) over all days as compared to the thoracic and lumbar regions and to the overall mean temperature. The lumbar region temperature was significantly greater on day 0 as compared to thoracic and pelvic regions but was not significantly different on any of the following days. The thoracic temperatures were significantly greater than the lumbar and pelvic regions on day 2 but there was no significant difference on any of the preceding or following days. There was no significant difference between left and right on any of the days. There was a correlation of the pelvic region temperatures on day 3 in relation to the presenting neurological grade.
Conclusion - Although there were varied heat patterns detected in dachshunds with IVDD, these patterns did not correlate with neurological grade, lesion site or lateralization of the lesion. Although there was a correlation between neurological grades and the pelvic region temperatures on day 3, this time period is unlikely to provide clinical utility.
Clinical Relevance - The results of this study suggest that thermography is not a useful tool for the diagnosis or prognosis of thoracolumbar disease in dogs in a clinical setting.
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Skin temperature variations in the coldFournet, Damien January 2013 (has links)
Skin temperature plays an important role in human thermoregulation together with core temperature. Skin temperature varies to a large extent across the body and this is especially pronounced in cold environments. The variations of skin temperature are also involved in the generation of regional thermal perceptions that can lead to behavioural adjustments. Whilst the temporal and inter-individual variations of skin temperature have been well studied using contact sensors, the knowledge of spatial variations has received less attention in the literature. Infrared thermography is a specific imaging technique particularly valuable for the exploration of the topography or pattern of skin temperature across the body. Most research using this technique has only been case studies or experiments focused in one specific body region. However, extensive regional skin temperature data over the whole-body can be proven useful for different types of applications including the sport clothing industry in combination with other body-mapping data. The primary aim of this thesis was to develop an original and standardised method using infrared thermography enabling whole-body skin temperature data to be compared for the assessment of spatial, temporal and inter-individual variations. A specific methodology for infrared data collection and data processing was successfully developed in order to combine data from a variety of participants varying in anthropometrical characteristics. The main outcomes were the production of several skin temperature body maps, either absolute maps to show the magnitude of the temporal or inter-individual effects, and normalised maps (relative to mean skin temperature) allowing for topographical comparisons between protocol stages, populations or interventions. The second aim of the thesis was to extend the understanding of the skin temperature patterns and how these could relate with thermal perceptions. The body-mapping method gave the opportunity to investigate a large amount of conditions, where various internal or external determinants of skin temperature were be involved. This was mainly done in cool to cold environments (5°C to 20°C) where skin temperature is not uniform but is associated with local and overall comfort. Studies were firstly performed in semi-nude conditions (Chapter 3, 4, 5) and then in clothed conditions (Chapter 6 and 7). The semi-nude studies were designed to explore the potential sexdifferences in regional skin temperature responses whilst running (Chapter 3) with a special interest in the role of skinfold thickness, this was further extended with a group of males at rest having a large variety of fat content and thickness (Chapter 4). The influence of exercise type and air temperature on skin temperature patterns was studied with a rowing exercise (Chapter 5). Studies were then performed in clothed conditions (Chapter 5, 6). The influence of real-life conditions on skin temperature patterns and associated perceptual responses was observed during a hiking scenario (Chapter 6). Following these descriptive studies, manipulation of skin temperature patterns was performed using clothing in order to determine the presence of any relevant effect on thermal comfort (Chapter 7). Our results demonstrated that the skin temperature pattern over the whole-body is relatively universal with several features being consistently found regardless of the conditions or the populations. The upper body is usually warmer than the lower body and the body creases (orbital, elbow regions etc.) are also warmer than surrounding regions. A Y-shape of colder temperatures has been highlighted over the anterior torso as well as a T- or Y-shape of warmer temperature over the posterior torso. There are yet some specificities that can be displayed due to active muscles during exercise such as the warmer skin overlying the trapezius and biceps muscles in rowing (Chapter 5), the influence of the backpack construction with up to 3°C warmer skin temperature in the lower back (Chapter 6) or the importance of additional clothing insulation minimizing the anterior Y-shape of colder skin temperatures (Chapter 7). Beyond the thermal patterns, absolute skin temperature differences have been observed between sexes with females displaying 2°C colder skin during semi-nude running (Chapter 3) and 1°C colder skin during clothed walking (Chapter 6)compared to males. The skin temperature difference can also be as large as 6°C colder skin for an obese male compared to a very lean male (40% vs 7% body fat). Despite these differences, there were almost no significant differences in overall and regional thermal sensations and comfort between sexes or between males with varying body fat. Our results focused on body fat revealed that overall fat content and sum of skinfolds was inversely associated with the mean skin temperature response during various protocols (Chapter 4, 6, 7). Local skinfold thickness explained the inter-individual variability of local skin temperature for resting (Chapter 4) and exercising males (Chapter 7) in most body regions. In terms of intra-individual variations, the distribution of skinfold thickness across the anterior torso explained the distribution of skin temperature in this segment solely in conditions with strong regional contrasts (Chapter 3, 4 and 7). When the whole-body skin temperature pattern is considered, our body-mapping approach failed to show relationships between skin temperature distribution across the body and regional skinfold thickness distribution neither at rest nor during exercise. The relative contribution of other internal determinants such as local heat production,local blood flow distribution and local anthropometry should be further investigated to fully elucidate the spatial skin temperature variations depending on the climate, clothing and the body thermal state. Lastly, there was a trend towards improved thermal comfort during rest and exercise in the cold through a manipulation of skin temperature patterns targeting the naturally cold body regions with high insulation, therefore obtaining a more homogeneous skin temperature distribution across the body (Chapter 7). The present work will benefit the sport goods industry. The descriptive results of skin temperature variations will be useful in order to validate multi-segmental model of human thermoregulation. Further work can include pattern predictions for exercise types and conditions not covered by the present thesis. The skin temperature maps will mainly feed the general body-mapping approach for clothing design taking into account several other body mapping data such as sweat mapping and the combination of cold, warm and wetness sensitivity mappings. Lastly, the present results have highlighted the interest for targeted solutions and also the need for more evolutive systems in the field of cold weather apparel.
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Computer-aided analysis of medical infrared imagesFord, Ralph M. (Ralph Michael), 1965- January 1989 (has links)
Thermography is a useful tool for analyzing spinal nerve root irritation, but interpretation of digital infrared images is often qualitative and subjective. A new quantitative, computer-aided method for analyzing thermograms, utilizing the human dermatome map, is presented. Image processing and pattern recognition principles needed to accomplish this goal are discussed. Algorithms for segmentation, boundary detection and interpretation of thermograms are presented. An interactive, user-friendly program to perform this analysis has been developed. Due to the relatively large number of images in an exam, speed and simplicity were emphasized in algorithm development. The results obtained correlate well with clinical data and show promise for aiding the diagnosis of spinal nerve root irritation.
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Investigation of Heat Conduction Through PMC Components Made Using Resin Transfer MouldingSakka, Aymen 16 November 2012 (has links)
The increasing demand for polymer matrix composites (PMCs) from the airframe industry raises the issues of productivity, cost and reproducibility of manufactured PMC components. Performance reproducibility is closely related to the manufacturing technique. Resin transfer moulding (RTM) offers the advantage of flexible manufacturing of net-shape PMC components with superior repeatability starting from ready-to-impregnate dry reinforcements. An RTM apparatus was developed for manufacturing PMC plates and demonstrator components representative of actual, PMC components and PMC moulds made and used in the airframe industry. The RTM process developed in this work involved making net-shape dry carbon fibre preforms and impregnating them an epoxy resin, targeting mould applications. Thermal repeatability of different net-shape PMC components manufactured using the RTM apparatus developed in-house was investigated. Effects of bonding an outer copper plate onto the PMC material, targeting mould applications known as integrally heated copper tooling (IHCT), were explored. Heat conduction through the PMC components was studied using simulation models validated by experimental data obtained primarily by thermography. Manufactured PMC components showed good repeatability, particularly in terms of thermal behaviour. The IHCT technique was found to be well suited for mould applications. Expected advantages of thermography were materialised. Finally, the simulation models developed were in good agreement with experimental data.
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Psychophysiology of the Sexuality of Women with Lifelong Vaginismus: A Matched Controlled Thermography and Survey Investigation of Sexual Function, Behaviour, and Physiological ArousalCherner, Rebecca A. 26 November 2012 (has links)
Vaginismus is defined as a persistent difficulty with vaginal entry, despite a woman’s expressed wish, due to muscle tension, avoidance, and/or pain (Basson et al., 2003). The disorder is classified as a sexual dysfunction; however, there is a paucity of literature on the sexual response, sexual function, and sexual behaviour of women with vaginismus. This thesis research was designed to investigate the differential aspects of sexual health in women with lifelong vaginismus, compared to women with lifelong dyspareunia (pain with intercourse) and women with pain-free intercourse. In the first study, 45 women viewed erotic films, of which one set depicted penetration and the other did not. Physiological sexual arousal was assessed via thermography. Subjective responses to films were assessed with questionnaires. Despite significantly greater negative emotions and lower mental sexual arousal in response to erotic stimuli, women with vaginismus showed genital arousal comparable to the comparison groups. In the second study, 174 women completed an online survey. Women with vaginismus reported more sexual difficulties than the no-pain group and a restricted range of lifetime sexual behaviours and lower frequency of intercourse attempts/experiences than the comparison groups. Women with vaginismus and dyspareunia reported more anxiety during sexual activity and a restricted sexual behaviour repertoire in the previous year and month compared to the no-pain group. Women with vaginismus endorsed more negative cognitions related to penetration, specifically concerns about losing control of their body and the situation. The findings suggest that sexual function difficulties and restricted behavioural repertoire may be associated with negative emotions and maladaptive cognitions. Women with vaginismus may avoid encounters that could lead to intercourse. Alternatively, the negative response to sexual stimuli may be indicative of a more global negative response to sexuality beyond intercourse. The negative penetration-related cognitions, negative responses to sexual stimuli, anxiety during sexual activity, and reduced range and frequency of sexual behaviours of women with vaginismus provide support for the Fear-Avoidance Model of Vaginismus. The impairment in sexual functioning supports the need to move beyond the singular treatment focus of making intercourse possible to an approach that addresses overall sexual rehabilitation.
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Evaluation of hand skin temperature -Infrared thermography in combination with cold stress testsLeijon Sundqvist, Katarina January 2017 (has links)
Abstract Since ancient times, warm or cold skin on the human body has been used as a parameter in evaluating health. Changes in body temperature are attributed to diseases or disorders. The assessment of body temperature is often performed to measure fever by detecting an elevated core temperature. With techniques such as infrared thermography, it is possible to perform a non-contact temperature measurement on a large surface area. The overall aim of this thesis was to contribute to a better understanding of the hand skin temperature variability in healthy persons and in persons experiencing whitening fingers (WF). The enclosed four papers discuss issues such as thermal variability response to cold stress test (CST) in repeated investigations; the specific rewarming pattern after CST; the difference between the hand’s palmar and dorsal temperatures; and evaluating skin temperatures and response to CST in participants with WF and healthy participants. All four papers used an experimental approach involving healthy males (I-III) and females (III) as well as individuals with (IV) and without WF (I-IV). Data were generated using dynamic infrared imaging before and after a CST. The radiometric images were analyzed using image analysis and statistics. The study showed that: (I) there is variability in hand skin temperature; (II) there are cold and warm hand skin temperature response patterns; (III) the skin temperatures on the palmar and dorsal sides of the hand are closely related; and (IV) a baseline hand skin temperature measurement can distinguish between whitening fingers and controls. The conclusion of this thesis is that it is necessary to engage in thorough planning before an investigation in order to choose the most adequate method for evaluating peripheral skin temperature response depending on the question asked.
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