Comparison of chest CT imaging between confirmed and suspected cases of COVID-19

ABSTRACT

Objective: To explore the value of chest CT features and clinical indexes in the differential diagnosis between suspected COVID-19 with two or more negative nucleic acid tests and confirmed COVID-19. Methods: The clinical data and chest CT images of 105 cases with confirmed COVID-19 (55 males and 50 females, aged from 2 month to 88 years) and 97 cases with suspected COVID-19 (59 males and 38 females, aged from 1 month to 93 years) were analyzed retrospectively in Shiyan Taihe Hospital from January 21 to February 10, 2020. χ2test and two independent sample t test were used to analyze the clinical data and CT signs of the two group cases, with P<0.05 for statistically significant difference. Results: Compared with the suspected patients, the average age of confirmed ones was higher (t=2.460, P=0.01). The main pathological changes were pure ground glass (68 cases) and mixed ground glass density (53 cases) (χ2=50.016, P<0.01). Interstitial thickening (83 cases) (χ2=55.395, P<0.01), vascular widening (73 cases) (χ2=57.527, P<0.01), air bronchogram sign or bronchiectasis (67 cases) (χ2=17.899, P<0.01), fibrous streak shadow (54 cases) (χ2=5.500, P=0.02), commonly distributed under the pleura and the long axis of the lesion was parallel to the pleura (89 cases) (χ2=23.597, P<0.01), most of them had no pleural effusion (χ2= 7.017, P<0.01);both lesions were mainly distributed in patches (89 confirmed cases, 87 suspected cases) (χ2=19.573, P< 0.01). In addition, the lesions of patients with confirmed COVID-19 showed progress in short term (72/87, 82.76%), and those with suspected COVID-19 showed remission in short term (63/89, 70.78%). The difference was statistically significant (χ2=51.114, P< 0.01). There was no significant difference in gender and distribution of pulmonary lobes (χ2=1.462, P=0.23;χ2= 7.381, P=0.19). The number of white blood cells (χ2=17.891, P<0.01) and the percentage of lymphocytes (χ2=11.151, P<0.01) of COVID-19 were mostly normal or decreased, creatine kinase (χ2=9.589, P<0.01) was mostly normal, and erythrocyte sedimentation rate was mostly normal or increased (χ2=4.240, P=0.04). Conclusions: The imaging features and biochemical indexes of diagnosed COVID-19 are different from those of suspected ones. The comparative analysis of imaging features, clinical indexes and follow up examination are helpful for the differential diagnosis of COVID-19.