key: cord-0939198-y4p916cg
authors: Zhu, Jieyun; Zhong, Zhimei; Li, Hongyuan; Ji, Pan; Pang, Jielong; Li, Bocheng; Zhang, Jianfeng
title: CT imaging features of 4121 patients with COVID‐19: A meta‐analysis
date: 2020-04-29
journal: J Med Virol
DOI: 10.1002/jmv.25910
sha: d03abf80cf2177fda85ae65d0f7b11c18c4e41a9
doc_id: 939198
cord_uid: y4p916cg

OBJECTIVE: We systematically reviewed the computed tomography (CT) imaging features of coronavirus disease 2019 (COVID‐19) to provide reference for clinical practice. METHODS: Our article comprehensively searched PubMed, FMRS, EMbase, CNKI, WanFang databases, and VIP databases to collect literatures about the CT imaging features of COVID‐19 from 1 January to 16 March 2020. Three reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies, and then, this meta‐analysis was performed by using Stata12.0 software. RESULTS: A total of 34 retrospective studies involving a total of 4121 patients with COVID‐19 were included. The results of the meta‐analysis showed that most patients presented bilateral lung involvement (73.8%, 95% confidence interval [CI]: 65.9%‐81.1%) or multilobar involvement (67.3%, 95% CI: 54.8%‐78.7%) and just little patients showed normal CT findings (8.4%). We found that the most common changes in lesion density were ground‐glass opacities (68.1%, 95% CI: 56.9%‐78.2%). Other changes in density included air bronchogram sign (44.7%), crazy‐paving pattern (35.6%), and consolidation (32.0%). Patchy (40.3%), spider web sign (39.5%), cord‐like (36.8%), and nodular (20.5%) were common lesion shapes in patients with COVID‐19. Pleural thickening (27.1%) was found in some patients. Lymphadenopathy (5.4%) and pleural effusion (5.3%) were rare. CONCLUSION: The lung lesions of patients with COVID‐19 were mostly bilateral lungs or multilobar involved. The most common chest CT findings were patchy and ground‐glass opacities. Some patients had air bronchogram, spider web sign, and cord‐like. Lymphadenopathy and pleural effusion were rare.

(Trial edition Fifth), issued on 4 February, added clinical diagnostic criteria, that was, the suspected cases with typical imaging features in Hubei were clinically diagnosed cases. 6 Integrating the first to seventh edition of the guideline, imaging has been playing a pivotal role in the diagnosis and treatment of this disease. Especially in hospitals that cannot perform NAAT, imaging can be a powerful tool for admission screening. Therefore, grasping the imaging features of patients with COVID-19 is of great significance for early screening and diagnosis, curbing the occurrence and development of the disease, and suppressing the speed of transmission.

Although many studies have been published on CT imaging of patients with COVID-19, most of them were single-center, and in the same hospital or region. Due to the different design and insufficient sample size, the imaging features of the published studies were different.

Moreover, there is still lack evidence-based medical evidence on the CT imaging features in patients with COVID-19 to guide clinical practice.

Therefore, we carried out this study to summarize the CT imaging features of COVID-19, to provide reference for further clinical practice.

This meta-analysis was carried out according to Preferred Reporting Items for Meta-Analyses of Observational Studies in Epidemiology (MOOSE) Statement. 7 PubMed, FMRS, EMbase, CNKI, WanFang databases, and VIP databases were electronically searched to collect studies about the CT imaging features of COVID-19 from 1 January 2020 to 16

March 2020. We also manually searched the lists of included studies to avoid missing any eligible study. When duplicate studies describing the same population, the most detailed or recent study was included. There was no language restriction placed on the searches, but only literatures published online were included. The search used a combination of subject words and free words, and adjusted according to different database characteristics. The search terms included: "Coronavirus" OR "2019-nCoV" OR "COVID-19" OR "SARS-CoV-2."

The inclusion criteria were as follows: (a) cohort studies, case-control studies, and case series studies; (b) the study population was patients 

Three researchers independently searched and screened the studies, collected data, and cross-checked. If there was a dispute, it was resolved through discussion or consultation with another researcher.

The content of the data extraction included: the first author's surname, the date of publication of the article, study region/country, study design, sample size, age, and CT imaging features; relevant elements of bias risk assessment.

The included studies of this meta-analyses were observational studies, so the British National Institute for Clinical Excellence (NICE) 8 was used to evaluate the study quality by two independent reviewers. This evaluation was conducted based on a set of eight criteria, and studies with a score greater than 4 were considered to be of high quality (total score = 8).

Meta-analysis was performed using STATA 12 (StataCorp, College Station, TX). Original incidence rates r were transformed by the double arcsine method to make them conformed to normal distribution, and the resulting transformed rate tr was used in metaanalysis. The heterogeneity between studies was analyzed using a χ 2 test (P < .10) and quantified using the I 2 statistic. When no statistical heterogeneity was observed, a fixed effects model was utilized.

Otherwise, potential sources of clinical heterogeneity were identified using subgroup analysis and sensitivity analyses, these sources were eliminated and the meta-analysis was repeated using a random effects model. Pooled incidence rates R were back-calculated from transformed rates tr using the R = [sin (tr/2)] 2 . A two-tailed P < .05 was considered statistically significant. Publication bias was evaluated using a funnel plot along with Egger's regression test and Begg's test.

A total of 4532 related articles were obtained in the initial retrieval.

After a detailed assessment based on the inclusion and exclusion criteria, 34 retrospective studies including 4121 patients with COVID-19 were included 9-42 ( Figure 1 ).

A total of 34 retrospective studies 9-42 that publicated from 6

February 2020 to 12 March 2020 were included. All studies were conducted in China, 16 of the studies included patients in Hubei Province, and the remaining 18 studies included patients in other provinces. All studies received quality scores of 5 to 8, indicating high quality (Table 1 ).

There were 73.8% of the COVID-19 patients presented bilateral lung involvement (95% CI: 65.9%-81.1%) and multilobar involvement 67.3% (95% CI: 54.8%-78.7%) (Figures 2 and 3 ). Single lung involvement (18.7%) and single lobe involvement (14.9%) were rare. A few patients showed normal CT manifestations(8.4%) ( Figure 4 and Table 2 ).

The lesion shapes included patchy ( 

Pleural thickening (27.1%, 95% CI: 15.6%-40.5%) was found in some patients. Lymphadenopathy (5.4%, 95% CI: 0.022-0.098), and pleural effusion (5.3%, 95% CI: 3.7%-7.3%) were rare ( Figure 6 and Table 2 ).

This study showed significant heterogeneity. To explore the source of heterogeneity, subgroup analysis was performed.

The results showed that the analysis results of the subgroups were basically consistent with the overall results, and there was no significant difference between the heterogeneity of the subgroups and the overall heterogeneity, which indicated that the study subject's location and sample size were not the main sources of heterogeneity (Table 3 ).

Sensitivity analysis was performed for the observation indicators of bilateral lung involvement, and statistics were recombined after excluding each study in turn. The results did not change substantially, suggesting that the results were stable (Figure 7 ).

The P values derived using Egger's and Begg's tests for all the observation indicators showed no obvious publication bias (Table 4) This study has several strengths including its large sample size and high quality of included studies. We conducted subgroup analysis according to studies' region and sample size. We also conducted sensitivity analysis by excluding each study one by one. The results did not change significantly, indicating the reliability and stability of our results.

Nevertheless, some limitations should be noted in our meta-analysis. retrospective studies, we were unable to control the influence of confounding factors. Lastly, this meta-analysis indicated a significant heterogeneity between the studies. But the subgroup analysis fails to eliminate all sources of heterogeneity, which may affect the accuracy of the results of meta-analysis.

To sum up, most patients presented bilateral lung involvement or multilobar involvement. The most common changes were groundglass opacities and air bronchogram sign. Other common changes included patchy, spider web sign, and so forth. Lymphadenopathy and pleural effusion were rare. But due to the quality and quantity of included studies, the above conclusions need to be confirmed by more high-quality studies. 

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The authors declare that there are no conflict of interests.

http://orcid.org/0000-0002-3174-1595Jianfeng Zhang http://orcid.org/0000-0003-4213-9310