Radiological findings from 81 patients with COVID-19 pneumonia in Wuhan, China: a descriptive study

Abstract

Background: A cluster of patients with coronavirus disease 2019 (COVID-19) pneumonia caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were successively reported in Wuhan, China. We aimed to describe the CT findings across different timepoints throughout the disease course.

Methods: Patients with COVID-19 pneumonia (confirmed by next-generation sequencing or RT-PCR) who were admitted to one of two hospitals in Wuhan and who underwent serial chest CT scans were retrospectively enrolled. Patients were grouped on the basis of the interval between symptom onset and the first CT scan: group 1 (subclinical patients; scans done before symptom onset), group 2 (scans done ≤1 week after symptom onset), group 3 (>1 week to 2 weeks), and group 4 (>2 weeks to 3 weeks). Imaging features and their distribution were analysed and compared across the four groups.

Findings: 81 patients admitted to hospital between Dec 20, 2019, and Jan 23, 2020, were retrospectively enrolled. The cohort included 42 (52%) men and 39 (48%) women, and the mean age was 49·5 years (SD 11·0). The mean number of involved lung segments was 10·5 (SD 6·4) overall, 2·8 (3·3) in group 1, 11·1 (5·4) in group 2, 13·0 (5·7) in group 3, and 12·1 (5·9) in group 4. The predominant pattern of abnormality observed was bilateral (64 [79%] patients), peripheral (44 [54%]), ill-defined (66 [81%]), and ground-glass opacification (53 [65%]), mainly involving the right lower lobes (225 [27%] of 849 affected segments). In group 1 (n=15), the predominant pattern was unilateral (nine [60%]) and multifocal (eight [53%]) ground-glass opacities (14 [93%]). Lesions quickly evolved to bilateral (19 [90%]), diffuse (11 [52%]) ground-glass opacity predominance (17 [81%]) in group 2 (n=21). Thereafter, the prevalence of ground-glass opacities continued to decrease (17 [57%] of 30 patients in group 3, and five [33%] of 15 in group 4), and consolidation and mixed patterns became more frequent (12 [40%] in group 3, eight [53%] in group 4).

Interpretation: COVID-19 pneumonia manifests with chest CT imaging abnormalities, even in asymptomatic patients, with rapid evolution from focal unilateral to diffuse bilateral ground-glass opacities that progressed to or co-existed with consolidations within 1-3 weeks. Combining assessment of imaging features with clinical and laboratory findings could facilitate early diagnosis of COVID-19 pneumonia.

Funding: None.

Figure 1

Number of involved lung segments at various timepoints from symptom onset Bars show the mean number of involved lung segments on CT scans from patients in group 1 (scan before symptom onset; n=15), group 2 (scan ≤1 week after symptom onset; n=21), group 3 (scan >1 week to 2 weeks after symptom onset; n=30), and group 4 (scan >2 weeks to 3 weeks after symptom onset; n=15).

Figure 2

Transverse thin-section CT scans in patients with COVID-19 pneumonia (A) 56-year-old man, day 3 after symptom onset: focal ground-glass opacity associated with smooth interlobular and intralobular septal thickening in the right lower lobes. (B) 74-year-old woman, day 10 after symptom onset: bilateral, peripheral ground-glass opacity associated with smooth interlobular and intralobular septal thickening (crazy-paving pattern). (C) 61-year-old woman, day 20 after symptom onset: bilateral and peripheral predominant consolidation pattern with a round cystic change internally (arrow). (D) 63-year-old woman, day 17 after symptom onset: bilateral, peripheral mixed pattern associated with air bronchograms in both lower and upper lobes, with a small amount of pleural effusion (arrows).

Figure 3

Distribution of various patterns of lung changes on CT scans at various timepoints from symptom onset Stacked bars show the proportion of patients in whom the predominant CT pattern was ground-glass opacity, reticular, mixed, or consolidation. Patients were grouped by time from symptom onset: group 1 (scan before symptom onset; n=15), group 2 (scan ≤1 week after symptom onset; n=21), group 3 (scan >1 week to 2 weeks after symptom onset; n=30), and group 4 (scan >2 weeks to 3 weeks after symptom onset; n=15).

Figure 4

Transverse CT scans from a 60-year-old man (day 8 after symptom onset) Selected images from CT scans at different levels. Extensive ground-glass opacities can be seen in both lungs, involving almost the entire lower lobes, and most of the upper lobes and right middle lobe, giving a white lung appearance, with air bronchograms. The patient died 4 days after this scan.

Figure 5

Transverse thin-section serial CT scans from a 77-year-old man (A) Day 5 after symptom onset: patchy ground-glass opacities affecting the bilateral, subpleural lung parenchyma. (B) Day 15: subpleural crescent-shaped ground-glass opacities in both lungs, as well as posterior reticular opacities and subpleural crescent-shaped consolidations. (C) Day 20: expansion of bilateral pulmonary lesions, with enlargement and denser pulmonary consolidations and bilateral pleural effusions (arrows). The patient died 10 days after the final scan.

Figure 6

Transverse thin-section serial CT scans from a 42-year-old woman (A) Day 3 after symptom onset: multifocal consolidations affecting the bilateral, subpleural lung parenchyma. (B) Day 7: the lesions had increased in extent and the density became heterogeneous, with internal bronchovascular bundle thickening. (C) Day 11: previous opacifications being dissipated into ground-glass opacities and irregular linear opacities. (D) Day 18: further resolution of the lesions. The patient was discharged from hospital 2 days after the final scan.