Chest CT versus RT-PCR for the detection of COVID-19: systematic review and meta-analysis of comparative studies

Abstract

Objectives: To compare the performance of chest computed tomography (CT) scan versus reverse transcription polymerase chain reaction (RT-PCR) as the reference standard in the initial diagnostic assessment of coronavirus disease 2019 (COVID-19) patients.

Design: A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A search of electronic information was conducted using the following databases: MEDLINE, EMBASE, EMCARE, CINAHL and the Cochrane Central Register of Controlled Trials.

Setting: Studies that compared the diagnostic performance within the same patient cohort of chest CT scan versus RT-PCR in COVID-19 suspected patients.

Participants: Thirteen non-randomised studies enrolling 4092 patients were identified.

Main outcome measures: Sensitivity, specificity and accuracy were primary outcome measures. Secondary outcomes included other test performance characteristics and discrepant findings between both investigations.

Results: Chest CT had a median sensitivity, specificity and accuracy of 0.91 (range 0.82-0.98), 0.775 (0.25-1.00) and 0.87 (0.68-0.99), respectively, with RT-PCR as the reference. Importantly, early small, China-based studies tended to favour chest CT versus later larger, non-China studies.

Conclusions: A relatively high false positive rate can be expected with chest CT. It is possible it may still be useful to provide circumstantial evidence, however, in some patients with a suspicious clinical presentation of COVID-19 and negative initial Severe Acute Respiratory Syndrome Coronavirus 2 RT-PCR tests, but more evidence is required in this context. In acute cardiorespiratory presentations, negative CT scan and RT-PCR tests is likely to be reassuring.

Keywords: COVID-19; CT; RT-PCR; accuracy; sensitivity; specificity.

Figure 1.

PRISMA flow diagram. The PRISMA diagram details the search and selection processes applied during the overview. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Figure 2.

Forest plot of chest CT – sensitivity and specificity for the identification of COVID-19 cases. CT: computed tomography; COVID-19: coronavirus disease 2019.

Figure 3.

Summary receiver operator characteristic (sROC) curves for the performance of chest CT in the initial diagnosis of COVID-19. CT: computed tomography. The x-axis also represents 1−specificity (in which case the figures would be from 0 to 1 reading from left to right).