Qualitative and Quantitative Study of Infrared Thermal Imaging of Acute Upper Respiratory Tract (Preprint)
Authors: Deng Fangge , Zhang Zuopeng , Cao ZanFeng , Yang Zhanzheng , Ma Sige , Guan Qianting , Liu Rong , He Zhuosen 
Published: July 2020

BACKGROUND

Acute upper respiratory infection often occurs in winter and spring, it is spread mainly through the use of food droplets containing influenza virus or the use of virus-contaminated robotic arms and other tools [1, 2]. They may also cause some local or other large-scale global climate changes and pandemics [3-4]. Because the antigen on the human surface of this subtype virus is easy to directly undergo immune mutation, new immune subtypes are generated, and there is no possibility of direct crossover between different new subtypes for immunization. Therefore, the disease not only occurs repeatedly within one year of the same person, but also causes widespread epidemics in a few years [5-6].
The far-infrared thermal imager is a non-invasive, non-toxic and objective temperature measurement method, which can provide information on changes in the function of the parasympathetic nervous system [7]. By collecting the far-infrared radiation heating from the human body, forming an intuitive temperature, processing a color map through the computer, using different colors to represent different human body surface temperature distributions, and accurately measuring the temperature distribution changes of the human body according to the difference between normal and abnormal infrared radiation [8], Judging by the scope and location of the focus, this is a functional image that can reflect the metabolism of the body, but the observation of subtle changes in tissue structure is not as good as CT or MRI [9-10]. Temperature is an important indicator that can reflect the pathophysiological state of the human body. The skin temperature of normal human body is basically symmetrical from limbs to head and face [11]. When people are suffering from diseases, the metabolism of local tissues and cells changes first, and this change is earlier than changes in human function or morphology.
Before the anatomical structure changes, molecular biology changes have occurred in the lesion and its surrounding tissues, which will further change the normal temperature of the lesion. The spatial distribution and gradient change of temperature will further reflect the specific scope of the disease and reveal the nature of the occurrence and development of the disease [12]. Far infrared thermal imaging technology is based on this principle, through a series of computer analysis and image processing technology to collect infrared information, formed thermal imaging, using different colors to display the temperature distribution of the human surface [13].
This article uses the method of experimental research to understand the impact of infrared thermal imaging qualitative and quantitative research, and the comparative exploration before and after the application; through theoretical analysis and experimental exploration, find out the role of infrared thermal imaging in the diagnosis of acute upper respiratory tract; Data is recorded, sorted, calculated, plotted, and analyzed to process the data, which is simulated by the infrared thermal imaging correlation data statistical data set of the acute upper respiratory tract, combined with the data, and empirical analysis of infrared expression of infrared thermal imaging technology for acute upper respiratory tract patients The location and characteristics, combined with effective data, summarize and analyze infrared thermal imaging technology has an important role in clearly expressing the quantification of temperature. The results show that with the method of this paper, the research effect is better.

OBJECTIVE

From December 2018 to February 2019, 154 AURI patients were randomly selected in the emergency department of the First Affiliated Hospital of Guangzhou Medical University. There are 73 men and 81 women. Ear: A general term for acute inflammation of the nose, pharynx, or throat. According to the fever, the subjects were divided into two groups: fever type and non-heat type. When the axillary temperature reaches the fever threshold (≥37.1 ℃), it is a fever type patient. Among them, 76 were in the fever group, the ratio of men to women was 40/36, the age range was 14-81 years, and the average age was 37.70 ± 18.54 years; 78 were in the non-fever group, the ratio of men to women was 33/45, the age range was 14-87 years, and the average age was 38.76 ± 17.19. Years old; 40 cases in the control group, the male to female ratio is 19/21, the age range is 19-80 years old, the average age is 39.20 ± 19 years old, 23 years old. All patients excluded head and face specific tissue specific high metabolism (such as tumors, infections, etc.), abnormally low metabolism (such as benign nodules, etc.), abnormal blood flow (such as hemangioma, etc.).

METHODS

Questionnaire: made according to the actual situation of the design. Including general personal and family information, previous medical history (whether there is tuberculosis, chronic bronchitis, asthma, hypertension, diabetes, etc.), smoking history, drinking history, personal history, acute upper respiratory tract infection within 1 year after physical examination. Statistical processing: SPSS20.0 computer data analysis software was used for single factor Logistic regression analysis. The dependent variable (defined as l, not defined as 0) is whether an acute upper respiratory tract infection occurs, and each study factor uses a single factor Logistic regression equation as the independent variable. Variables with statistical significance (P <0.05 selected), and then multiple unconditional logistic regression model was fitted to the selected variables.
Using far infrared thermal imager atir-m301b and uncooled focal plane digital thermal imaging technology, the temperature resolution is 0.05 ℃, and the spatial resolution is 2mrad. In the examination room without obvious air convection, the room temperature is controlled at (23 ± 2) ℃. Before the inspection, expose the test site until the signs are stable and the skin temperature is appropriate. When the equilibrium temperature of the detection environment is 5-15min, a far infrared thermal imager is used to collect the far infrared thermal images of the head and face. The far infrared thermal imager can scan and collect the infrared thermal energy emitted by the human body, and through computer analysis and processing, it can express different temperatures with different colors, making it an intuitive far infrared thermal image. By observing the images, we can accurately analyze changes in body surface temperature due to changes in the nervous system and analyze diseases. We can discover the disease at an early stage and observe the changes and results of the disease in time. It has the characteristics of safety, convenience and low cost. Can be checked repeatedly to dynamically observe the changes in the condition. The drawing environment temperature is 22-24 ℃, no heat source interference, humidity 50% -60%, no strong light, no wind. The instrument complies with national standards (GB / t1965-2005). The instrument is equipped with a 320 × 240 uncooled focal plane infrared collection lens. The spectral response is 8 ~ 14μm, the spatial resolution (IFOV) is 1.3mrad, the temperature resolution is 0.05 ℃, and the acquisition speed is 30 frames / s. In the form of pseudo-color heat, the thermal structure of the human body can be displayed objectively and digitally. All subjects were prepared in accordance with infrared thermal imaging testing specifications before the test. During the test, the subjects took the correct sitting posture, exposed the examination site, 2 meters away from the infrared lens, 1 face upright, 2 face up and so on. Focusing, temperature calibration, image acquisition, storage, image processing, etc [44].
Qualitative index of infrared thermal image evaluation: observe the expression and distribution characteristics of infrared thermal image. Different color scales represent different temperatures. Among them, white: super high temperature zone; red: high temperature zone; pink: hot zone; yellow: warm zone; yellow: cool zone is green or green; green: blue or blue low temperature zone; black: ultra low temperature zone. Compare changes in color scale between groups. Quantitative Index: The average temperature corresponding to the extracted temperature is quantitatively compared with the patients with no fever and the left and right nasal areas and the left and right sides of the pharynx, AURI and the control group without fever. Statistical processing: extract the data from the corresponding part of the infrared software system, and use SPSS20.0 statistical software to organize [45]. The measurement data is expressed as "mean ± standard deviation ( ±S)". Compare the average temperature by analysis of variance, and then compare the two.

RESULTS

According to the statistical analysis of the data, as shown in Figures 1 and 2, the normal group is mainly "low temperature" blue or green, and the infrared expression on the left and right sides has good symmetry, and the average temperature difference does not exceed 1 ° C; The expression is similar, and the corresponding body surface area is focal or large-scale focal or diffuse pink hot zone or red hot zone; the thermal group is more obvious than the non-thermal group. Infrared temperature measurement technology avoids direct contact between the thermometer and the object and does not affect the temperature field distribution of the object. It can ensure high temperature measurement accuracy. The high-performance infrared thermometer can distinguish the temperature difference of 0.01 ℃. Quick temperature measurement. Infrared thermometers respond very quickly to temperature and can be used for real-time and fast tracking measurements. This advantage makes infrared temperature measurement technology widely used in steel, electricity, forest fire prevention and many other aspects. Wide temperature measurement range. Infrared temperature measurement technology has a wider application range than traditional temperature measurement methods. In theory, infrared temperature measurement has no upper limit. In practical applications, infrared thermometers can measure low temperatures of tens of degrees below zero and high temperatures of thousands of degrees. There is no time limit, you can work day and night. Due to the characteristics of infrared, night work has become a highlight of infrared thermometers. It can measure micro target temperature. It is not limited by the distance and can measure the temperature in a short distance or a long distance.
According to the statistical analysis of the data, as shown in Figure 3 and Table 1, the average temperature of the infrared thermal image of the corresponding body surface area of the nasal cavity and larynx in the fever group is higher than that in the non-heat group; but the average body temperature of the two groups is higher than that of the normal control group (P <0.01). There are many methods of infrared temperature measurement. According to different methods, current infrared temperature measuring instruments can be divided into two categories: one is infrared temperature measuring equipment based on full-field analysis; the other is infrared temperature measuring system based on point-by-point analysis. The principle of full magnetic field analysis is that the temperature distribution of the entire object is an infrared focal plane array imaging infrared lens, and the temperature distribution of the entire object constitutes the infrared thermal image of the object, and the infrared temperature measurement equipment of the complete field distribution is also called infrared heat Imager; the measurement principle of point-by-point analysis is to focus part of the infrared radiation on an object through an infrared detector, and then according to the object with known surface emissivity, the radiant power of the object is converted into temperature information, and we can easily measure the phase In comparison. This point-by-point analysis system is usually called an infrared thermometer.
According to the statistical analysis of data, as shown in Figure 4 and table 2, there are 135 cases of acute upper respiratory tract infection, including 24.08% for males and 22.71% for females. The difference was not statistically significant by P > 0.05 test. As we all know, men smoke more than women, and women smoke less than men. Smoking is a risk factor for respiratory infection. First of all, the harmful substances in tobacco will destroy the immune monitoring cells in the airway, i.e. phagocytes, so that their phagocytic capacity and lethality will be reduced. Secondly, smoking can stimulate the proliferation of goblet cells, which secrete a lot of mucus and less antibodies, which is conducive to the growth of bacteria. At the same time, smoking will destroy the cilia of the ciliated columnar epithelial cells of the respiratory tract, make them shorter, irregular or incomplete, and make the sputum unable to be discharged smoothly.
According to the statistical analysis of data, as shown in Figure 5, the prevalence of male upper respiratory tract infection is 46.51% , female 33.20% , smokers 30.63% . It can be seen that smokers are more likely to have acute upper respiratory tract infection than nonsmokers (P<0.05). At the same time, there was also a significant difference between men and women (P<0.05). Male patients with hypertension 29.82% , women with hypertension 29.86% . It can be seen that the incidence of acute upper respiratory tract infection in patients with hypertension was higher than that in patients without hypertension (P<0.05). At the same time, there was no significant difference in the proportion of men and women with hypertension. Smoking can also directly stimulate the airway, cause airway spasm, and affect sputum drainage. The above adverse factors can weaken the defense ability of the respiratory tract, and the respiratory tract infection causes the damaged ciliated columnar epithelial cells to develop into squamous epithelium gradually. On the one hand, it weakens the purification ability of the airway, on the other hand, it also has the risk of canceration. As an independent and serious risk factor of respiratory tract infection, smoking has attracted more and more attention in recent years. The most common respiratory diseases associated with smoking are lung cancer, bronchitis and emphysema.

CONCLUSIONS

(1) IRTI can provide an objective and quantifiable reference for the visual diagnosis of AURI people, and can be used as one of the effective indicators of clinical diagnosis. There are obvious abnormal expressions of infrared thermography in the corresponding parts of the body surface.
(2) The pathological features of acute sinusitis and acute pharyngitis are the inflammatory changes with vascular exudation as the central link, and the local manifestation is elevated body temperature.
(3) Because IRTI is highly sensitive to vascular disease or inflammation, infrared detection can show that the average temperature of the nasal cavity area and the middle neck throat area of the corresponding surface of acute sinusitis and acute pharyngitis is significantly higher, showing typical abnormal thermal images.