Interpretation of chest CT scan of patints with COVID-19 in Imam Khomeini Hospital of Jiroft University of Medical Sciences from December to March 2019

Along with laboratory testing, chest CT scans may be helpful to diagnose COVID-19 in individuals with a high clinical suspicion of infection. Due to their availability and rapid turnaround time, the role of chest computed tomography (CT) scan is growing for early diagnosis of patients with COVID-19. However, due to the low efficiency of viral nucleic acid detection as well as low specificity of chest CT scan for detecting COVID-19 pneumonia, this method shows incomplete clinical performance for proper COVID-19 disease diagnosis. Due to the highly contagious nature of the  Coronavirus 2019 and the importance of early detection of the disease, a limited number of nucleic acid test kits, such as rRT-PCR and the possibility of false-negative rRT-PCR results, chest CT scan as a non-invasive method, it can be a highly accurate tool for early detection of suspected COVID-19 cases. The purpose of this study was the Interpretation of chest CT scan of patints with COVID-19 in Imam Khomeini Hospital of Jiroft University of Medical Sciences from December to March 2019

This research is a retrospective study that was conducted with the aim of interpreting CT scans of the chest in patients with covid-19 in Imam Khomeini Hospital, Jiroft University of Medical Sciences from March 2018 to June 2019. After obtaining permission from the ethics committee of the university, the researcher appeared in the research environment according to the pre-determined schedule for sampling. The desired data were extracted from the patients' files and recorded in a questionnaire form that was designed for this purpose. The criteria for entering the study included cases whose demographic information, clinical and laboratory data were complete and the positive PCR test along with chest CT imaging findings were available in the file, the exclusion criterion was the presence of low quality chest images.The data were extracted from the hospital information system based on clinical electronic medical records. including demographic information including age, sex, level of education and data related to the underlying disease, disease symptoms (cough, fever, phlegm, shortness of breath, chest pain, etc.) and the frequency of imaging findings in the chest CT scan that They were examined and evaluated according to age, gender, level of education, clinical symptoms, underlying disease and based on lymphopenia and lymphocytosis. and chest CT scan report of patients with COVID-19, which was available in the PACS system of this hospital, were evaluated. In this way, all the CT images of the chest by a radiologist as well as a lung specialist who were not aware of the clinical and laboratory data of the patients, in terms of the types of findings include, Patchy ground glass opcification, diffuse ground glass opacification, Air space opacity, Consolidation, pleural effusion, Atelectasis, Bronchiectasis, Fibrotic change, Cavitation, Lymphadenopathy. And the distribution of conflict was investigated as peripheral, central, bilateral, and unilateral.

The highest number of people with Covid-19 were in the age range of 30 to 59 years and men. In CT scan findings, the highest CT scan imaging findings as well as the highest mortality rate in patients were PGGO view (63.3%) and peripheral and bilateral involvement and the lowest frequency was related to Cavitation findings. In the examination of CT scan findings, PGGO and peripheral and bilateral involvement were the most frequent and Cavitation was the least frequent. Also, the findings of PGGO, Peripheral and Bilateral in the CT scan of the people who died had the highest frequency.In none of the imaging findings of the chest scan, there was no statistically significant relationship with the level of education, the level of education and death of patients due to COVID-19 . There was no significant difference between gender and the findings of PGGO  and Cavitation and peripheral involvement and Bilateral , but between the findings of DGGO and gender and there was a significant relationship between Bronchiectasis and gender. In general, the results showed that there is no significant relationship between gender and death of patients due to COVID-19. In terms of symptoms, the findings showed that there is no significant relationship between the symptoms of myalgia, chest pain, loss of sense of smell and taste, and digestive symptoms and CT scan findings, but between the feeling of weakness and Peripheral involvement, there was a statistically significant difference between the decrease in level of consciousness and the finding of Pleural effusion and the finding of CavitationP, and in general, a statistically significant relationship was observed between the death of patients and myalgia and the decrease in level of consciousness.

Among findings of this research, the symptoms of cough, fever, shortness of breath, and headache were present in most of the patients. In line with this finding, Kazemini and colleagues also concluded in their study that fever and cough are two important factors in identifying patients with Covid-19 is high . In this study, CT scan findings in the form of PGGO, Peripheral and Bilateral had the most frequency, which was also reported in a study that at the time of the onset of the disease, the findings of PGGO and Bilateral distribution were the most frequent in CT scans of patients . The reason that the lesions have a marginal distribution and are not limited to certain parts of the lung lobes can probably be due to the small size of the virus, which has a greater tendency to deposit in the peripheral lobes of the lung and thus cause damage to the epi The telium becomes alveolar and affects several adjacent lobules . Also, according to Wei li et al.'s study, GGO is the most common chest CT imaging manifestation in pneumonia caused by the corona virus, which indicates that the pneumonia of COVID-19 mainly includes interstitial secretions. This means that the pathological mechanism of the disease is secondary to the expansion and congestion of alveolar capillaries and interstitial edema in the interlobular septum . unlike COVID-19, in SARS, most cases of lung involvement are unilateral.In the present study, the findings of Air space opacity and Consolidation imaging were also found to be of high frequency compared to other findings, in the study of SONG et al., it was also reported that GGO image is more frequent in young people and Consolidation image is more frequent with increasing age. This issue is also evident in the present study, so that Consolidation was less frequent at ages less than 30 years compared to ages 30-59 years. Consolidation is one of the characteristics of CT in patients with COVID-19, which is a sign of disease progression, Pan et al. found that consolidation is rare in the early stages of the disease. Consolidation begins to appear with the progress of the disease and gradually becomes the main imaging feature. Therefore, the analysis of chest CT imaging can help the doctor in identifying the early stages or the progress of the disease. By identifying the common findings in chest CT scan in people with coronavirus, based on appropriate epidemiological and demographic characteristics, COVID-19 cases can be identified in a timely manner and immediate preventive measures can be taken. Therefore, due to the accuracy of this diagnostic tool and its rapid results, CT imaging should be at the forefront of COVID-19 screening tools and easy access to it in different areas compared to rRT-PCR kits should be provided.