COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

Diagnosis Sun Z, Zhang N, Li Y, et al. A systematic review of chest imaging findings in COVID-19. Quant Imaging Med Surg. 2020 May;10(5):1058-1079. doi: 10.21037/qims-20-564.

Chest computed tomography (CT) is frequently used in diagnosing coronavirus disease 2019 (COVID-19) for detecting abnormal changes in the lungs and monitoring disease progression during the treatment process. Furthermore, CT imaging appearances are correlated with patients presenting with different clinical scenarios, such as early versus advanced stages, asymptomatic versus symptomatic patients, and severe versus nonsevere situations. However, its role as a screening and diagnostic tool in COVID-19 remains to be clarified. This article provides a systematic review and meta-analysis of the current literature on chest CT imaging findings with the aim of highlighting the contribution and judicious use of CT in the diagnosis of COVID-19. A search of PubMed/Medline, Web of Science, ScienceDirect, Google Scholar and Scopus was performed to identify studies reporting chest imaging findings in COVID-19. Chest imaging abnormalities associated with COVID-19 were extracted from the eligible studies and diagnostic value of CT in detecting these abnormal changes was compared between studies consisting of both COVID-19 and non-COVID-19 patients. A random-effects model was used to perform meta-analysis for calculation of pooled mean values and 95% confidence intervals (95% CI) of abnormal imaging findings. Fifty-five studies met the selection criteria and were included in the analysis. Pulmonary lesions more often involved bilateral lungs (78%, 95% CI: 45-100%) and were more likely to have a peripheral (65.35%, 95% CI: 25.93-100%) and peripheral plus central distribution (31.12%, 95% CI: 1.96-74.07%), but less likely to have a central distribution (3.57%, 95% CI: 0.99-9.80%). Ground glass opacities (GGO) (58.05%, 95% CI: 16.67-100%), consolidation (44.18%, 95% CI: 1.61-71.46%) and GGO plus consolidation (52.99%, 95% CI: 19.05-76.79%) were the most common findings reported in 94.5% (52/55) of the studies, followed by air bronchogram (42.50%, 95% CI: 7.78-80.39%), linear opacities (41.29%, 95% CI: 7.44-65.06%), crazy-paving pattern (23.57%, 95% CI: 3.13-91.67%) and interlobular septal thickening (22.91%, 95% CI: 0.90-80.49%). CT has low specificity in differentiating pneumonia-related lung changes due to significant overlap between COVID-19 and non-COVID-19 patients with no significant differences in most of the imaging findings between these two groups (P>0.05). Furthermore, normal CT (13.31%, 95% CI: 0.74-38.36%) was reported in 26 (47.3%) studies. Despite widespread use of CT in the diagnosis of COVID-19 patients based on the current literature, CT findings are not pathognomonic as it lacks specificity in differentiating imaging appearances caused by different types of pneumonia. Further, there is a relatively high percentage of normal CT scans. Use of CT as a first-line diagnostic or screening tool in COVID-19 is not recommended.

Discipline / Specialty Area Score
Infectious Disease
Intensivist/Critical Care
Hospital Doctor/Hospitalists
Internal Medicine
Pediatric Neonatology
Pediatric Hospital Medicine
Comments from MORE raters

Hospital Doctor/Hospitalists rater

The results are consistent with findings for most, if not all, viral pneumonias--nonspecific.

Hospital Doctor/Hospitalists rater

This is an overall summary of CT chest findings in COVID-19. I'm not sure how useful it will be for clinicians looking after these patients as the study is very non-specific.

Hospital Doctor/Hospitalists rater

Because of the rating system's two question structure, my rating is higher than I think this article really deserves. I doubt that the article adds much to the knowledge base of its primary target audience - radiologists, but it does help by summarizing the literature, and adds flesh to the bones of our picture of COVID-19 pneumonia.

Infectious Disease rater

CT enjoyed a brief period where it was considered an screening modality for COVID-19, but the findings suggestive of COVID-19 are nonspecific; this review nicely summarizes the limits of imaging in this setting, and should help put to rest protocols which use this expensive tool for asymptomatic screening.

Intensivist/Critical Care rater

This is a good synthesis clearly showing the limitation of CT scan in diagnosing COVID-19.

Pediatric Hospital Medicine rater

Accumulating knowledge on COVID is important but this study does not have pediatric patients and so is of limited use to pediatricians.