Utility of chest CT in diagnosis of COVID-19 pneumonia

Abstract

Purpose: We aimed to explore the imaging findings of computed tomography (CT) in diagnosing coronavirus disease 2019 (COVID-19) and its clinical value for further evaluation of suspected cases.

Methods: Files of 155 patients visiting the fever clinics at our hospital and affiliated hospitals from January 20th to February 9th, 2020 were searched. Among them, 140 cases (including 82 males and 58 females) were included as suspected COVID-19 cases based on clinical and epidemiological history; the CT image features of 70 cases with suggestive findings on CT, confirmed by positive nucleic acid test were analyzed and evaluated. The sensitivity and specificity of CT in diagnosing COVID-19 were evaluated in patients with epidemiological history.

Results: Of the 70 patients, 84.3% showed bilateral lung involvement on CT; 27 cases (38.6%) showed ground-glass opacity (GGO), which was mostly distributed in the subpleural area (55.7%), and this sign was mainly observed in early COVID-19 patients. In addition, 41 cases (58.6%) manifested GGO combined with focal consolidation opacity, 2 (2.8%) had flake-like consolidation opacity, with involvements of the periphery of lung field and the central zone (44.3%), and this sign was mostly observed in severe or critical patients. Concomitant signs such as pleural effusion and mediastinal lymph node enlargement were rare. Among patients with epidemiological history, the sensitivity of CT in diagnosing COVID-19 was 89.7% (70/78), and the specificity was 88.7% (55/62).

Conclusion: CT shows high sensitivity and specificity in diagnosing COVID-19. CT is an important examination method in evaluation of suspected cases and assessment of disease severity.

Figure 1

Flowchart of nucleic acid detection and CT diagnosis in 155 patients.

Figure 2. a, b

Early stage CT findings of COVID-19. Axial CT image (a) of a 46-year-old female presenting with fever for 3 days. Flake-like ground-glass opacities are observed in the subpleural areas of upper lobes of bilateral lungs, in which thickened small vessels (black arrows) are seen. Axial CT image (b) of a 34-year-old male presenting with fever and cough for 6 days. A large sheet-like ground-glass opacity is seen in the upper lobe of left lung, in which the grid opacities are observed with the slabstone sign (black arrows).

Figure 3. a, b

Progressive stage CT findings of COVID-19. Axial CT images (a, b) of a 28-year-old female presenting with fever and cough for 7 days. Multiple flake-like ground-glass opacities and consolidation opacity are observed in bilateral lungs, most remarkably in the lower lobes; bronchial meteorology (black arrow) is seen in local lesion.

Figure 4. a, b

Progressive stage CT findings of COVID-19. Axial CT images (a, b) of a 52-year-old male presenting with fever for 5 days and diarrhea. Multiple sheet-like ground-glass opacities are observed in both lungs, which are more obvious in the right lung.

Figure 5. a, b

Critical stage CT findings of COVID-19. Axial CT images (a, b) of a 69-year-old male presenting with fever and dry cough for 6 days. Multiple diffuse ground-glass opacities and consolidation opacity are observed in both lungs, which show “white lung” sign.

Figure 6. a, b

CT findings of common pneumonia. Axial CT image (a) of a 34-year-old female presenting with fever and cough for 4 days. Strip-like ground-glass opacities are observed in the subpleural areas of the upper lobes of bilateral lungs (black arrows), and thickened small vessels are observed inside. Axial CT image (b) from re-examination after 5 days of treatment. The lesion in subpleural areas of the upper lobes of bilateral lungs are obviously absorbed. The patient was clinically diagnosed with common pneumonia.