Systematic review and meta-analysis of chest radiograph (CXR) findings in COVID-19

Abstract

Chest radiography (CXR) is most likely to be the utilized modality for diagnosing COVID-19 and following up on any lung-associated abnormalities. This review provides a meta-analysis of the current literature on CXR imaging findings to determine the most common appearances of lung abnormalities in COVID-19 patients in order to equip medical researchers and healthcare professionals in their efforts to combat this pandemic. Twelve studies met the inclusion criteria and were analyzed. The inclusion criteria consisted of: (1) published in English literature; (2) original research study; (3) sample size of at least 5 patients; (4) reporting clinical characteristics of COVID-19 patients as well as CXR imaging features; and (5) noting the number of patients with each corresponding imaging feature. A total of 1948 patients were included in this study. To perform the meta-analysis, a random-effects model calculated the pooled prevalence and 95% confidence intervals of abnormal CXR imaging findings. Seventy-four percent (74%) (95% CI: 51-92%) of patients with COVID-19 had an abnormal CXR at the initial time of diagnosis or sometime during the disease course. While there was no single feature on CXR that was diagnostic of COVID-19 viral pneumonia, a characteristic set of findings were obvious. The most common abnormalities were consolidation (28%, 95% CI: 8-54%) and ground-glass opacities (29%, 95% CI: 10-53%). The distribution was most frequently bilateral (43%, 95% CI: 27-60%), peripheral (51%, 95% CI: 36-66%), and basal zone (56%, 95% CI: 37-74%) predominant. Contrary to parenchymal abnormalities, pneumothorax (1%, 95% CI: 0-3%) and pleural effusions (6%, 95% CI: 1-16%) were rare.

Keywords: COVID-19; CXR; Chest radiograph; Coronavirus; Imaging; Meta-analysis; SARS-CoV-2.

Fig. 1

A forest plot illustrating results of the meta-analysis on pooled prevalence values for abnormal CXR in COVID-19 patients. Each study is represented by one line in this figure, depicting the 95% CIs, and each box in the center describes the proportion for that study comparison. The effect size of each box to the hollow blue diamond represents the strength or the weight that particular study gives to the overall meta-analysis (% Weight). The hollow blue diamond denotes the prevalence value from the pooled-effects model; the center of the diamond gives the overall proportion while the extremities illustrate the 95% CI. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 2

Cases illustrative of consolidation on CXR (a) Consolidation (arrows) in the left lower lung zone (b) Vertical air space consolidation along the left costal margin (c) Dense consolidation in the right lower zone

Fig. 3

Cases illustrative of ground-glass opacity (GGO) on CXR (a) Patchy GGOs with peripheral distribution in the right lung (b) Peripheral GGOs in mid- and lower-third of thorax (c) Bilateral GGOs more prominent in the right upper lobe and right paramediastinal region

Fig. 4

Cases illustrative of bilateral peripheral air opacities on CXR (a) Bilateral ground-glass alveolar consolidation with peripheral distribution (b) Bilateral ill-defined, patchy alveolar consolidation with peripheral distribution

Fig. 5

Cases illustrative of atypical imaging findings on CXR (a) Bilateral pleural effusion and diffuse interstitial thickening (b) Bilateral pneumothorax and pneumomediastinum with diffuse air space in both lungs