Value of chest digital radiography in the initial diagnosis of secondary cases of COVID-19

Abstract

Objective To analyze the value of chest digital radiography (DR) in the initial diagnosis of secondary cases of COVID-19. Methods The radiological data from Beijing COVID-19 information and resource management platform "COVID-19 image database" were retrospectively analyzed. Twenty confirmed cases, including 14 males and 6 females (32-80 years old, mean 51.2±15.1 years old), who performed chest computed tomography (CT) scan and DR during his/her first visit to clinic were included. The interval times between CT and DR examination were from 1 to 53 hours, (mean 25.4±22.8 hours). According to the results of CT scan, the diagnostic ability of DR was analyzed. McNemar’s test was used to analyze the agreement between the diagnoses based on the CT and DR findings. Bland-Altman or Kappa analysis was used to analyze the consistency in number, distribution, and morphological features of the lesions identified on the CT and DR. Results COVID-19 was identified in 19 of 20 cases by using CT (107 lesions), and 17 of 20 cases by using DR (54 lesions), respectively. The diagnostic accuracy of CT and DR was 95%, 85%, respectively. There was no statistical significance in diagnostic ability between DR and CT (P=0.5). For the determination of bilaterally distributed lesions, patterns of distribution among different lobes, diffused distribution and the morphological features of the lesions, the consistencies between the results of DR and CT were well (κ>0.6, respectively). The consistency between DR and CT is poor when recognizing multiple lesions(≥5). DR diagnosed two cases as normal, both presented as single pure ground glass opacity on CT, and the longest orthogonal diameters were 0.8 cm (≤1 cm) and 1.9 cm (1~3 cm). Conclusion Chest DR can be used to diagnose patients with COVID-19 if combined with the epidemic hsitory. However, it is difficult for DR to identify single lesion with lower density in patients with mild symptom. A CT scan in time will provide additional information. Key words: COVID-19; Tomography, X-ray computed; Digital radiography