Thin-Section Chest CT Imaging of COVID-19 Pneumonia: A Comparison Between Patients with Mild and Severe Disease

Abstract

Purpose: To compare radiologic characteristics of coronavirus disease 2019 (COVID-19) pneumonia at thin-section CT on admission between patients with mild and severe disease.

Materials and methods: Seventy patients with COVID-19 pneumonia who were admitted to Zhongnan Hospital of Wuhan University between January 20, 2020 and January 27, 2020 were enrolled. On the basis of the World Health Organization guidelines, 50 patients were categorized with the mild form and 20 with the severe form based on clinical conditions. Imaging features, clinical, and laboratory data were reviewed and compared.

Results: Patients with the severe form (median age, 65 years; interquartile range [IQR]: 54.75-75.00 years) were older than those with the mild form of disease (median age, 42.5 years; IQR: 32.75-58.50 years) (P < .001). Patients with the severe form of disease had more lung segments involved (median number of segments: 17.5 vs 7.5, P ≤ .001) and also larger opacities (median number of segments with opacities measuring 3 cm to less than 50% of the lung segment: 5.5 vs 2.0, P = .006; ≥ 50% of lung segment: 7.5 vs 0.0, P < .001). They also had more interlobular septal thickening (75% vs 28%, P < .001), higher prevalence of air bronchograms (70% vs 32%, P = .004), and pleural effusions (40% vs 14%, P = .017).

Conclusion: Ground-glass opacities with or without consolidation in a peripheral and basilar predominant distribution were the most common findings in COVID-19 pneumonia. Patients with the severe form of the disease had more extensive opacification of the lung parenchyma than did patients with mild disease. Interlobular septal thickening, air bronchograms, and pleural effusions were also more prevalent in severe COVID-19.© RSNA, 2020.

Figure 1:

Axial CT images in a 51-year-old man with fever, fatigue, mild dyspnea, and confirmed with COVID-19. A, B, The baseline noncontrast thin-section chest CT on January 20, 2020 shows pure ground-glass opacity (white arrows) in bilateral lobes and mainly peripheral sections. The largest lesion is located in the lower lobe of the left lung. C, D, Fourteen days later, follow-up chest CT was performed. The opacities increased significantly in both lower lobes, with more consolidation (short black arrows) and a little parenchymal band (long black arrow) appearing.

Figure 2:

CT images in a 65-year-old woman with fever, dyspnea, fatigue, and confirmed with COVID-19. A, B, Axial noncontrast thin-section chest CT shows typical COVID-19 imaging characteristics. Bilateral lobes of pure ground-glass opacity (white arrows), ground-glass opacity with consolidation (short black arrow), intralobular interstitial thickening (crazy-paving pattern) (asterisks) and air bronchogram (long black arrows) are identified.

Figure 3:

The noncontrast thin-section CT images in a 39-year-old man with fever and fatigue for 5 days and confirmed with COVID-19. A, Pure ground-glass opacity lesion (white arrow) located in left lower lobe. B, Five days later, another follow-up chest CT scan was performed. The pure ground-glass opacity lesion turned to consolidation (short black arrow) and parenchymal band (long black arrow).

Figure 4:

The noncontrast thin-section chest CT in a 61-year-old woman with fever and dyspnea, confirmed with COVID-19 (A, B: axial CT; C: coronal CT; D: sagittal CT). The imaging shows interlobular septal thickening (black arrow) and crazy paving (asterisks). Opacities located predominately in the peripheral areas of both lungs.

Figure 5:

The noncontrast thin-section chest CT in a 53-year-old man with fever and confirmed with COVID-19. The CT image shows pleuroparenchymal interface irregularity (black arrows) and consolidation (asterisks).