Top PDF Infrared thermography: A non-invasive window into thermal physiology

Infrared thermography: A non-invasive window into thermal physiology

Infrared thermography: A non-invasive window into thermal physiology

Analysing thermal images, especially videos from conscious and active animals is a laborious process. Unlike many of the applications for which IRT was developed (physics, engineering), animals are rarely stationary with respect to the captured image frame, so any time-based analyses are plagued with changes in shape, perspective, and distance, and existing thermographic software packages appear to lack automation features that include object tracking along with temperature analysis. To date, the author is not aware of software packages that incorporate thermal analysis with motion sensing or object tracking, although customized solutions could be achieved with sufficient computation skills and access to existing analytical platforms (Abramoff et al., 2004; MATLAB, 2015). Typically, users are required to draw a region of interest (ROI) over the surface they wish to examine and simple mean, minimum, maximum and standard deviation of the pixels within the ROI is possible. The most powerful programs allow for ROI data to be examined over time. With respect to physiological data, movement artifacts typically make these impossible to use. One of the limiting factors in infrared thermal imaging is the file format. Image files are not always saved in a publically accessible format and require commercial software for analysis. Although normally provided at the time of purchase, unless the user has computer programming skills, they are at the whim of the company supplying the software. Open source alternatives to these commercial software packages are not available at present (Minkina and Dudzik, 2009), however, customized approaches could be employed (see supplementary
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Comparative accuracy of Digital Infra red Thermal Imaging(DITI) in breast cancer diagnosing

Comparative accuracy of Digital Infra red Thermal Imaging(DITI) in breast cancer diagnosing

Breast cancer is one of the leading causes of death among women. Early diagnosis can increase the survival rate in cancer patients. Digital Infrared Thermal Imaging (DITI) is a portable and non-invasive diagnostic technology that is non-contact, pain-free and radiation free procedure for breast carcinoma diagnosis. However, the link between disease and heat radiation is complex and in many cases even non-linear. The DITI shows sensitivity of 97.6%, specificity of 99.17%, positive predictive value 83.67% and negative predictive value 99.89% on breast thermography screening. The aim of this study was to review recent studies published on the application of infrared thermography for the evaluation of safety, effectiveness and diagnostic accuracy for breast cancer screening and diagnosis based on breast thermography. This work systematically examines the evidence on breast thermography as a tool for screening/ diagnostic test to assist in the investigation of abnormalities on a mammogram or ultrasound and to assess the risk of future breast cancer. It is concluded that there is currently insufficient evidence to recommend the use of DITI merely as a diagnostic tool. This inefficiency mainly causes during image acquisition, complicated processing and analyzing of the thermograms and most importantly, lack of standard protocols to guide the final prediction. Therefore, the demand for a proper image processing method is still an opened discussion. Future research on employing standardized imaging and reporting methods is still required.
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Micro Calcifications Detection for Breast Cancer Diagnosis using Infrared Thermal Imaging Apparatus

Micro Calcifications Detection for Breast Cancer Diagnosis using Infrared Thermal Imaging Apparatus

In this paper a noble model of thermograms imaging apparatus,which may have an impact towards the pattern study of a woman breast is introduced. Infrared (IR) thermography determines the surface temperature of an object or human body using thermal IR measurement camera. It is a method which is contactless and completely non-invasive. These properties make IR thermography a useful method of analysis that is used in various areas to detect, monitor and predict irregularities in many fields from engineering to medical and biological observations. System integrating passive thermal imaging with geometrical data from active scanner or an IR camera. We outline the potential benefits of this system in medical applications. In particular, we emphasize the benefits of using this system for preventive detection of breast cancer. The model deals with the potentials which are left ahead in regular diagnosis of women to determine Microcalcifications for diagnosis of abnormal growth in the breast tissues and cancer.
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The synthesis of multisensor non-destructive testing of civil engineering structural elements with the use of clustering methods

The synthesis of multisensor non-destructive testing of civil engineering structural elements with the use of clustering methods

Non-destructive testing (NDT) methods, such as ground penetrating radar (GPR), ultrasonic, impact-echo (IE) and infrared thermography (IRT), are due to the non-invasive effect they have on the structure more and more often used as an alternative for visual inspection in combination with destructive tests on samples extracted from the structure. However, with respect to the composition and condition of the inspected structure, all methods exhibit different penetration capability and sensitivity to the material physical properties. Hence, an extensive sensitivity evaluation should be carried out with respect to several not yet standardized applications. It is evident that regardless of the knowledge about the methods’ performance, multi-sensor testing is required for a complete inspection of the structure. This also rises the need for an efficient and reliable data processing technique. Contrary to most data fusion methods, clustering does not require the knowledge about the structural composition and can thus work unsupervised. In the thesis their functioning was tested on the results from the inspection of concrete and masonry structures. Hard and fuzzy clustering algorithms were analysed. As a hard clustering algorithm, the k-means was taken into account, whereas for the fuzzy ones, the conventional fuzzy c-means (FCM) and its variants were used. These are either better suited for handling noisy data (noise handling fuzzy c-means (NCFCM), possibilistic c-means (PCM) with repulsion, possibilistic-fuzzy c-means (PFCM)) or use an adaptive distance norm (Gustafson-Kessel (GK)). The main research on the possibilites of defect detection in the near-surface region was performed on four laboratory concrete specimens using GPR and IRT. In the analysis, the material prop- erties, type, shape and size of anomalies were taken into account. Particularly, voids, localized water, delamination, plastic pipes and reinforcement were simulated. Special consideration was put on the data evaluation of the results using pulsed thermography. Techniques based on the thermal contrast and pulsed phase thermography (PPT) were employed. The phase contrast images enabled accurate depth characterization of anomalies and deeper probing. In addition, they exhibited high contrast and good spatial resolution. Thus, for the sensitivity evaluation of GPR and IRT, phase contrast images were used together with GPR C-scans. The evaluation revealed that the sensitivity of GPR is lower than the one of IRT up till a depth of 3–4.5 cm. For IRT, the sensitivity decreases only slowly up till 7.5 cm, which particularly resulted from using phase contrast images. For both methods it could be observed that the material characterization of defects is predominantly governed by the contrast in dielectric constant and thermal conduc- tivity between defects and sound area. Hence, GPR more accurately detects a water anomaly than an air anomaly, and the opposite is true for IRT.
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Non-invasive diagnosis of viability in seeds and lichens by infrared thermography under controlled environmental conditions

Non-invasive diagnosis of viability in seeds and lichens by infrared thermography under controlled environmental conditions

Infrared images were recorded at a speed of 1 frame per minute during 4 days (seeds; Experiment 1) or 1 frame per second during 170  min (lichens, Experiments 2–4) with a FLIR A320 (FLIR, USA) camera, generating a data set of > 8000 frames per experiment. The IR camera was equipped with an uncooled microbolometer focal plane array detector, with a spectral range of 7.5–13 μm wave- length, an IR resolution of 320 × 240 pixels and a thermal sensitivity < 0.05 °C at 30 °C. Emissivity was set at 0.96 as is typically used for plant material [15], and RH recorded (values shown in Additional file  1: Table  S1). Infrared images were taken at an approximate distance of 0.5  m above the samples and analysed in the img-format fol- lowing a modification of the method described in [11]. Using the ResearchIR 4 software (FLIR Systems, Inc., USA), rectangular "regions of interest" (ROIs) with an area of 50–100 pixels were placed in the centre of each sample area and on several reference areas taken from fil- ter paper covering empty wells of the sample rack (Addi- tional file  1: Fig. S1). Each ROI covered approximately 90% of each sample surface, thus representing its overall surface temperature. The absolute temperature values (T) were averaged over all pixels per sensor area. The relative temperature (rT) of a sample at a certain time point t i was
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Thermography Quantification of Human Perfusion Thermal Signature

Thermography Quantification of Human Perfusion Thermal Signature

Abstract: Blood perfusion quantification is important vital parameters in different diagnostic procedure, using infrared thermography imaging; it is reliable to use this technique as non-contact, non-invasive blood flow measurement method. Therefore, we developed a measurement protocol for blood flow over the arm’s anterior surface. By using the superficial brachial and radial veins to be monitored under the impact of cold-excitation of (2 °C to 5 °C), the blood perfusion signal was detected using thermal imager of long-wave infrared spectral range (LWIR, 7 µ m - 14 µ m). The simulation of Penne’s bioheat transfer equation was performed to be compared with results obtained from the infrared thermography. Furthermore, the proposed blood flow m onitoring u sing e xternal a djusting o f t he e xcitation t emperature, b y using (cold-compress, or cold air-stream) applied to the region under testing. The signal detected resembles to the hemodynamic pulse of the superficial veins, in the definition of systolic and diastolic phases of the cardiac cycle. Moreover, statistical analysis applied to the BFIRT signals from 24 subjects to estimate the skin’s mean temperature after recovery from the thermal excitation.
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Neonatal non-contact respiratory monitoring based on real-time infrared thermography

Neonatal non-contact respiratory monitoring based on real-time infrared thermography

preliminary and need further studies in a larger number of neonates and under differ- ent care setups. The mathematical method needs further improvement, such as auto- matic ROI definition and automatic calibration. Furthermore, the IRTR monitoring may assist in the estimation of a possible temperature loss as a part of thermoregula- tion, and may be also considered as a first step to evaluate non-invasive respiratory behaviour of premature infants [33]. In comparison to the ECG derived respiration rate, the IRTR signal is correlated to this acquired signal from bedside monitor, while there is a slight difference in respiration rate estimated from each method (see Table 1). The main impediments to high resolution IRTR signature detection are the IR cam- era physical coverage and the thermal detector’s resolution. In spite of the calibration mechanism in modern thermal cameras, most of medical IR imaging setups face cali- bration drift; and this needs enhancement in order to avoid erroneous measurement. To deal with this problem, the proposed solution is based on a virtual sensing mechan- ism to track the ROI over a defined anatomical part. Moreover, the information on intensity was extracted and transformed into a corresponding color-coded space of IR thermographic images.
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Non Invasive Glucose Measurement Techniques using Near Infrared Spectroscopy

Non Invasive Glucose Measurement Techniques using Near Infrared Spectroscopy

The major difficulties faced by the non-invasive technique includes the indirect way of measurement and the calibration issues[17].The indirect way of measurement makes them vulnerable to low signal to noise ratio; which can be combated by considering a comprehensive evaluation of measurement which covers various physical and chemical tissue parameters [18]. Being non-invasive, which is an indirect technique of measuring glucose, a time lag can occur between the measurements of blood glucose content from different parts of body, which can be repaired using an algorithmic approach. Device calibration is a concern when user- friendly and usability concept is considered. A user –oriented approach by implementing the system through a mobile app has completely made it popular and will yield a higher subject satisfaction in future.
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Determination of Thermal Contact Conductance in Vacuum-Bagged Thermoplastic Prepreg Stacks Using Infrared Thermography

Determination of Thermal Contact Conductance in Vacuum-Bagged Thermoplastic Prepreg Stacks Using Infrared Thermography

Thermal contact resistance between composite prepreg stacks has been studied mainly in the frame of thermoplastic tape placement [3,4], or in an environment at ambient pressure [5]; it has been shown that an increase in compaction pressure leads to better heat transfer along the stack thanks to a better intimate contact between plies. Analytical models exist that allow the determination of thermal contact resistance as a function of applied pressure, for example through Hertzian contact theory [6]. However, the case in which the compaction pressure is generated by mean of a vacuum bag has not been investigated.
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Impact damage evolution under fatigue loading by InfraRed Thermography on composite structures

Impact damage evolution under fatigue loading by InfraRed Thermography on composite structures

Abstract. This study deals with cumulative damage and its evolution in already impact damage composite structure. In order to follow the growing damage and to compare it with cumulative model, tests are monitored with an InfraRed thermography system. A carbon-epoxy composite is first low-energy impacted and then fatigued under tension- compression loading. This study also enables a very fast analysis of predicting the damage evolution coupling InfraRed Thermography as NDT method and InfraRed thermography as a following system.
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Application of infrared thermography in computer aided diagnosis

Application of infrared thermography in computer aided diagnosis

In the world of mechanics, increased friction develops heat and causes wear which can led to material failure [1]. Therefore, heat pattern and indeed heat pattern changes give a good indication of machine health [2]. By a striking coincidence, diagnosing via heat pattern is not limited to mechanical systems both electronic and biological systems follow the same pattern. Especially, the human body temperature has been linked to health since the time of Hippocrates [3]. Since then, the diagnostic accuracy was linked to the instruments used for temperature measurement. Therefore, the discovery and capture of Infrared (IR) radiation from the human body, by Herschel in 1800, was a big step forward [3]. These measurements are based on the physical phenomena, that all objects, including the human body, with a temperature above absolute zero (-273 K) emit IR radiation from their surface [4]. Experiments showed that human skin emits IR radiation essentially in the range of 2–20 µm wavelengths, with an average peak at 9–10 µm. Despite this understanding, it took until 1934 before Hardy described the physiological role of IR emission from the human body. He put forward that both physi- ological processes and thermal properties of the skin are influenced by a wide range of factors, because the skin helps to manage the core body temperature. These factors change in the presence of disease, hence IR measurements can be used for diagnos- tic purposes [5]. This fundamental understanding paved the way for IR thermography as a body imaging modality for medical sciences. The first use of this new technology was reported in the year 1960, it took so long because quality equipment and tech- nical knowhow was unavailable [6]. Since 1963 it is known that heat patterns, shown in thermographic images taken with IR cameras, provide information about physical anomalies, such as cancer, especially breast cancer, infection, eye disease, diabetes and pain [7]. However, having a qualitative statement based on general observations is something different from a quantitative statement, which expresses how useful the method is for medical diagnosis [8]. In terms of medical applications, the usefulness of a particular diagnostic method can be expressed in terms of the ability to deliver a correct diagnosis, the side effects and the cost.
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3D Visualization of thermal resistance and condensation problems using infrared thermography for building energy diagnostics

3D Visualization of thermal resistance and condensation problems using infrared thermography for building energy diagnostics

2) Continuous measurement to form time-series of thermal resistances: Besides the measurement accuracy issues, a few responders described ‘4D visualization’ as a desired feature, e.g. “Maybe a 4D visualization done with the presence of all the objects that exist in the building.”, “A time series IR webcam of a building over the course of a year.” In prior work on measuring actual U-values (Fokaides and Kalogirou 2011), the results were validated based on different sources of information: instantaneous surface temperature data samples of 10 measurements obtained from a thermal camera and continuous time-series heat flux data collected from HFMs over a period of 168 hours. According to the experimental results, it is shown that the outcomes of the two methods were very close to each other in terms of their accuracies. However, if surface temperature data can be collected continuously, the actual heat resistances can be modeled and explored in 4D (3D + time) as opposed to static information. Visualizing dynamic energy performance metrics in form of a 3D animation can significantly improve the understanding of time-varying heat transfer phenomena. This also enables to provide an opportunity to analyze the impacts of building envelope retrofit decisions. For example, energy auditors can conduct a before/after analysis on thermal resistances when additional insulation layers are being installed. Such analyses would support implementation of periodic building maintenance programs. More research on 4D visualization of energy performance metrics need to be conducted; and finally
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Drying Evaluation Using Infrared Thermography

Drying Evaluation Using Infrared Thermography

x Thermal images are not very conclusive regarding the drying process as thermal patterns resulting from dirt at the surface and different thermal conductivity of inner layers may mask the drying process identification and difficulties in isolating the effect of solar radiation, wind and air temperature prejudice the interpretation; x Nevertheless, some encouraging results were obtained as a reduction on the surface temperature are in line with

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Applications of infrared thermography in the food industry

Applications of infrared thermography in the food industry

Ten Fresh potato samples (Solanum tuberosum L. cv. Melody) were tempered at 4ºC before starting the experiment. Ten fresh potato samples were peeled and cut with a cylindrical core borer in order to obtain cylinders with 45 mm diameter and 70 mm height. Potato samples were removed from the refrigerator, placed in the freezer (Dycometal, S.L. model ACR-45/87) and maintained at -20 ºC. During the freezing process, the surface temperature was recorded with an infrared thermocamera (Thermal Imager optris PI160 with 120 Hz frame rate, detector with 160 x 120 pixels), see figure 29. The volume of the samples during freezing process was determined by image analysis of the pictures captured with thermocamera every three minutes. The image analysis was made with Adobe Photoshop®. Moreover, different thermocouples (Thermometer model HIBOK 14) were used to register the temperature of potato surface, the internal temperature of potato and the temperature of the freezer. Volume, mass, surface water activity, sugar content (º Brix), moisture and dielectric properties were measured for every sample before and after freezing process. Mass was determined using a Mettler Toledo (±0.0001) (Mettler-Toledo, Inc., USA) balance.
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Application of the method of active thermography in wooden structures of nineteenth century buildings

Application of the method of active thermography in wooden structures of nineteenth century buildings

To the validation of the preliminary inspection is satisfactory the use of good practices that involve the geometric survey of the dimensions of the elements, evaluation of the characteristics of the materials, as well as the characterization of the structural damages (MARTINS, 2009). Interventions in wooden structures often involve partial alterations in a building, so it is necessary to maintain dimensions and characteristics of historical importance. Thus, inspection methods that investigate the actual state of the structure and reduce the impacts of substitutions are critical. Oliveira et al. (2005) state that with an effective damage mapping it is possible to make the most precise decision about the maintenance or rehabilitation technique to be adopted in the intervention. In this context, nondestructive tests (NDT) applied to historical structures have advantages because they do not damage the structural capacity of the material, because of the speed of execution and relatively low cost. Cortizo et al. (2008) define the thermography method as a non-destructive test, without the need of contact with the body or system, for the visual identification of the surface thermal gradient, provided that it is in ambient conditions based on the capture of the infrared radiation, which allows detecting heterogeneities in constructive elements and systems. For Figueiredo et al. (2017), the thermographic method consists in the recording of images by color scales of perception of the surface temperature of a body, being possible, through this technique, to detect temperature changes that identify potential pathological problems. Thermographic tests allow qualitative and quantitative analysis of the results. The qualitative analyzes, characterized by being simpler approaches
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Infrared Thermography and its Application in Building Construction

Infrared Thermography and its Application in Building Construction

Infrared camera is a simple device and can be handled with usual precaution like an ordinary photographic camera. The image have to be focused and composed to same way. The focus, composition and ranges of temperature chosen cannot be altered later, though brightness and contrast can be adjusted in the image to highlight the required details. It is essential to focus the camera for sharp images compose the significant details being monitored , and set the temperature ranges for useful result. The images are processed by software to yield thermal images. Various thermal pattern can be obtained from by varying the palette (colour pattern), brightness and contrast of the image for locating details and correct interpretation of the image. Various colour palette can be selected, including grey palette. Thermal images appear as zone of different colours or shades depending upon temperature ranges and mean temperature selected. It should be mentioned here that the visual colours do not necessarily reflect the temperature pattern (thermal images).The bright region in a thermal images indicate the high temperature ,while the dark region indicated the low temperature and intermediate region marked by coloures ranging from white to black through yellow , orange ,red and indigo. On a grey palette, various shades ranging from white (high temperature) to black (low temperature) distinguish the region of reducing temperature. Figures indicated a typical example; the visual images show the seepage of
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Characterisation of damage in composite materials using infrared thermography

Characterisation of damage in composite materials using infrared thermography

As discussed in the previous subsections, different methods are available for optical IR thermography. The methods differ in the heat source and the heat signal used for the heat deposition and the process- ing method for the measurement data. An overview of these differences has been provided in Table 2.1. Due to the fundamental differences between the methods, the results obtained also differ. PT and PPT deposit heat on the object using a pulse signal. PT is sensitive to uneven heating and reflections of the surface making it unsuitable for large surface in-situ inspections. PPT is less sensitive to these factors since the phase is analysed for each pixel separately. PPT is however limited in the amount of heat that can be deposited on the surface due to the pulse length. Both PT and PPT require very high powered lamps in order to deposit enough heat on the surface in a few millisecond duration flash. Frequency domain analysis with a sine wave or a chirp signal spreads the energy deposition over a longer time. The long duration low peak power heat deposition makes deeper defects detection pos- sible without overheating the object and with only a limited peak power required from the lamps. The pulse compression analysis also uses low peak power long duration signals, but these signals are processed using CC resulting in different thermography results. The pulse compression analysis results in a higher SNR than the frequency domain analysis.
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Thermal sensation in older people with and without dementia living in residential care: new assessment approaches to thermal comfort using infrared thermography

Thermal sensation in older people with and without dementia living in residential care: new assessment approaches to thermal comfort using infrared thermography

To experience a thermally comfortable indoor environment, an older person living in residential care relies almost entirely upon decisions made by others. This is typically the care home staff who will regulate the temperature of the communal spaces and bedrooms. For those residents with dementia, simple interventions to adjust the physical stimuli of light, noise and temperature can improve a persons quality of life [1] experience [2] and behaviour [3]. Thermal comfort therefore, becomes an important aspect of wellbeing and quality of life, which may require a different set of indoor thermal adjustments (including clothing) than required for active younger people.
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A Infrared hyperspectral imaging technique for non-invasive cancer detection.

A Infrared hyperspectral imaging technique for non-invasive cancer detection.

Abstract:- Hyperspectral imaging(HI) is an emerging technology in the field of biomedical engineering which may be used as a non-invasive modality for cancer characterization. In this project, we propose to investigate hyperspectral imaging for the characterization of gastric cancer. The hyperspectral imaging has been used for the detection of various kinds of human cancer; breast, gastric, prostate and tongue. A research group has also investigated the use of reflectance imaging to detect canine cancer using fluorescent dyes. The use of hyperspectral imaging, however, has been limited for the characterization of cancer. In this project, we have already acquired many hyperspectral images of tumors. The malignant tissue has relatively low reflectance intensity compared to the benign tissue. The decreased reflectance intensity observed for malignant tumors is due to the increased microvasculature and therefore higher blood content of cancerous tissue relative to benign tissue. In the future, we will normalize and preprocess the spectral dataset. We propose to apply various algorithms such as Support Vector Machine, Linear Discriminant Analysis and Principal Component Analysis on the spectral data to discern the malignant and benign tumors. The advantage of cancer detection using hyperspectral imaging is that it is non-invasive, highly efficient and less time consuming than traditional methods like biopsy.
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Non-invasive studies of arterial physiology in children and adults at risk of atherosclerosis

Non-invasive studies of arterial physiology in children and adults at risk of atherosclerosis

A principal problem confronting preventive medicine has been the identification of asymptomatic people likely to develop atherosclerosis. In the absence of a safe and accurate screening method for visualising arterial plaques, a risk factor concept has evolved and been applied in several health promotion research programmes (MRFIT 1976, Lipid Research Clinic 1984). Many of these risk factors, such as serum total cholesterol and blood pressure, have been measured in epidemiologic surveys of children (Lauer et al 1975, Morrison et al 1977). Despite the fact that risk factor tracking occurs in adolescents and in children over 6-9 years (Clarke et al 1978, Freedman et al 1985), a substantial proportion of children with initially elevated vascular risk factors show reduced levels at follow-up. Thus the problem of identifying people in early life at high risk for adult cardiovascular disease persists. In recent years, however, non-invasive techniques for the diagnosis and assessment of atherosclerosis have improved; in particular, vascular ultrasound has the potential for safe, reliable, and cost-effective
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