Objective:

To dynamic differential diagnosis on 2019 novel coronavirus (COVID-19) pneumonia and interstitial pneumonia caused by chemoradiotherapy (IP-CRT) by using CT examination.

Methods:

A total of 73 patients with COVID-19 pneumonia from Jan. 2020 to Mar. 2020

and 44 patients with IP-CRT from Dec. 2019 to Mar. 2020 were enrolled in the First Affiliated Hospital of USTC. We evaluated the dynamic chest CT features of these lesions

including the distribution

extent

form

density

main and other features.

Results:

① Initial positive CT revealed that both the two groups manifested as multifocal

bilateral

multiple lobe lesions with multiple form of ground-glass opacities (

P

＞0.05). Linear opacities

fine grid shadow

crazy paving pattern

bronchial changes and pleural thickening existed in both the two groups (

P

＞0.05). Peripheral/subpleural distribution

halo/reversed halo sign and vascular changes could be seen more common in COVID-19 pneumonia (

P

＜0.05). Vacuole/cavity sign

pleural effusion and lymph node enlargement happened in IP-CRT more common (

P

＜0.05). ② In clinical progression

lesions of COVID-19 pneumonia showed that multiple patchy opacities merged into large opacities with consolidation pattern and crazy paving pattern. The location and manifestation of IP-CRT were various. ③ In clinical recovery phase

COVID-19 pneumonia could manifested as the sign of ground-glass nets hanged on the trees

and the fibrotic linear opacities could disappear over time; but the fibrotic linear opacities would exist for a long time in IP-CRT

with decreased pleural effusion and recovery lymph nodes (

P

＜0.05).

Conclusion:

CT features has good value in differential diagnosis for the occurrence

progression and recovery of COVID-19 pneumonia and IP-CRT.