Other studies in HRCT findings
is an important component in the diagnostic procedure for patients with suspected COVID-19 infection. Chest CT has limited sensitivity and negative predictive value early after symptom onset, and has little weakness in diagnosis of COVID-19 combined to personal history, clinical symptoms, and initial laboratory findings, and may therefore serve as a standard method for diagnosis of COVID-19 based on its features and transformation rule, the limited number of RT- kits in some centers before initial RT- screening (Bernheim et al., 2020, Chen et al., 2020). Although 12% of patients were without abnormal lung changes on initial CT images in present study.
In a study, the most HRCT findings were bilateral parenchymal ground-glass opacities, without or with consolidation in the lung periphery. Especially, 75% patients with chest HRCT findings related to COVID-19 pneumonia had negative results of concurrent nucleic acid tests (He et al., 2020). Then, 21.70% of positive chest HRCT patients in present study had normal CRP. According to imaging examination in a study, 75% patients showed bilateral pneumonia, 14% patients showed multiple mottling and ground-glass opacity, and 1% patient had pneumothorax (Chen et al., 2020).
In a study, The CRP, ESR, and LDH presented significantly positive correlation with the pneumonia severity on CT. The highest temperature and the severity of opacifications assessed on initial CT were significantly related to the progression of opacifications on follow-up CT(Xiong et al., 2020). In present study, LDH had significantly positive correlation with HRCT. In a study, GGO was the most common manifestation of COVID-19 pneumonia, which could be followed by consolidation and fibrosis.Total CT score, GGO score and fibrosis score of male patients were significantly higher than female in the second week. Male patients had higher consolidation score and fibrosis score than female in the third week. Total CT score and GGO score had weak to moderate correlation with arterial blood gas indices (Shang et al., 2020). In our study, 42.30% of women and 57.70% of men had positive HRCT for COVID- a meta-analysis, 40 studies with 4183 COVID-19 patients, the rate of positive CT scan in COVID-19 patients was 94.5%. Bilateral lung involvement, GGO pulse consolidation or reticular, consolidation, reticular, presence of nodule findings and GGO, in CT scan of COVID-19 pneumonia patients were respectively estimated to be 64.9% , 49.2% , 30.3% , 17.0% ,16.6%, 94.5% . The lung lesions distribution in patients with COVID-19 was 70.0% peripheral, 3.9% central, and31.1% peripheral and central (Karimian and Azami, 2020). In a study, of 1014 patients, 59% had positive RT- results, and 88% had positive chest CT scans. The sensitivity of chest CT in suggesting COVID-19 based on positive RT- results was 97%. In patients with negative RT- results, 75% had positive chest CT findings; 48% were categorized as highly likely cases, with 33% as probable cases. 60% to 93% of cases had positive CT consistent with COVID-19 prior to the initial positive RT- results (Ai et al., 2020).
A total of 14 articles including 1115 patients, pure GGO 69%, consolidation 47% and “air bronchogram sign” 46% were more common than the atypical lesion of “crazy-paving pattern” 15%. while 67% of patients showed a predominant peripheral distribution (Wan et al., 2020). In a study, included 52% men, and the mean age was 49·5 years. The major pattern of abnormality observed was bilateral 79%, peripheral 54%, and GGO 65%. A weak relevance was between the fibrosis score and the value of PaO2 and SpO2(Dai et al., 2020). There was a statistically significant association between level of O2 saturation and HRCT results in present study. In a study, with median age of 45 , 98% patients had evidence of abnormal CT compatible with viral pneumonia at baseline (Fang et al., 2020).
It suggested the critical importance to combine the two methods in the early stage of the disease to exclude the SARS-CoV-2 infection. These CT performances of COVID-19 were similar to previous studies. The O2 saturation decreased in patients, which were in consistence with the alteration of indices in patients with lung involvement. the bilateral GGO was higher in the present study. Our results support the use of chest CT for screening for -19 for patients with clinical and laboratory features compatible with COVID-19 infection(Shi et al., 2020). Additionally, a positive relevance was found between the HRCT score, O2 saturation, that was, a patient with higher CT score tended to have lower O2 saturation.