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. 2020 Sep;30(9):4910-4917.
doi: 10.1007/s00330-020-06880-z. Epub 2020 Apr 22.

Characteristic CT findings distinguishing 2019 novel coronavirus disease (COVID-19) from influenza pneumonia

Hao Wang  1 , Ran Wei  1 , Guihua Rao  2 , Jie Zhu  3 , Bin Song  4
Affiliations

Characteristic CT findings distinguishing 2019 novel coronavirus disease (COVID-19) from influenza pneumonia

Hao Wang et al. Eur Radiol. 2020 Sep.

Abstract

Objectives: To investigate the different CT characteristics which may distinguish influenza from 2019 coronavirus disease (COVID-19).

Methods: A total of 13 confirmed patients with COVID-19 were enrolled from January 16, 2020, to February 25, 2020. Furthermore, 92 CT scans of confirmed patients with influenza pneumonia, including 76 with influenza A and 16 with influenza B, scanned between January 1, 2019, to February 25, 2020, were retrospectively reviewed. Pulmonary lesion distributions, number, attenuation, lobe predomination, margin, contour, ground-glass opacity involvement pattern, bronchial wall thickening, air bronchogram, tree-in-bud sign, interlobular septal thickening, intralobular septal thickening, and pleural effusion were evaluated in COVID-19 and influenza pneumonia cohorts.

Results: Peripheral and non-specific distributions in COVID-19 showed a markedly higher frequency compared with the influenza group (p < 0.05). Most lesions in COVID-19 showed balanced lobe localization, while in influenza pneumonia they were predominantly located in the inferior lobe (p < 0.05). COVID-19 presented a clear lesion margin and a shrinking contour compared with influenza pneumonia (p < 0.05). COVID-19 had a patchy or combination of GGO and consolidation opacities, while a cluster-like pattern and bronchial wall thickening were more frequently seen in influenza pneumonia (p < 0.05). The lesion number and attenuation, air bronchogram, tree-in-bud sign, interlobular septal thickening, and intralobular septal thickening were not significantly different between the two groups (all p > 0.05).

Conclusions: Though viral pneumonias generally show similar imaging features, there are some characteristic CT findings which may help differentiating COVID-19 from influenza pneumonia.

Key points: • CT can play an early warning role in the diagnosis of COVID-19 in the case of no epidemic exposure. • CT could be used for the differential diagnosis of influenza and COVID-19 with satisfactory accuracy. • COVID-19 had a patchy or combination of GGO and consolidation opacities with peripheral distribution and balanced lobe predomination.

Keywords: Coronavirus; Influenza; Pneumonia; Tomography, X-ray; Virus.

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Conflict of interest statement

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Figures

Fig. 1
Fig. 1
Distribution of pulmonary lesions. Volume rendering reconstruction was implemented into images a–d. a Central distribution. b Diffuse distribution. c Non-specific distribution. d Peripheral distribution
Fig. 2
Fig. 2
GGO lesion involvement pattern. Volume rendering reconstruction was implemented into images a–d. And e–g were the original thin-slice images. a Cluster-like involvement pattern (white arrow). b Patchy involvement pattern (white arrow). c Combination of GGO and consolidation opacities pattern (white arrow). d Whole consolidation pattern (white arrow). e Image e showed cluster-like GGO along the bronchial tree in the right inferior lobe. f Image f showed multifocal patchy GGO located in bilateral lung inferior lobe. g Image g showed combination of GGO and consolidation opacities (arrow). h Image h showed whole consolidation
Fig. 3
Fig. 3
a–c A 60-year-old female patient with COVID-19 showing patchy GGO, shrinking GGO contour (black arrow), and peripheral distribution in bilateral lungs. d–f A 69-year-old female patient with COVID-19 showing combination of GGO and consolidation opacities, shrinking GGO contour (black arrow), and non-specific distribution
Fig. 4
Fig. 4
a–c A 33-year-old male patient with influenza A pneumonia showing diffuse cluster-like GGO along the bronchial tree and bronchial wall thickening (black arrow) with central distribution. d–f A 38-year-old male patient with influenza B pneumonia showing bronchial wall thickening (black arrow) and vague cluster-like GGO along the bronchial tree located in the inferior lobe
See this image and copyright information in PMC

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