Diagnostic accuracy of X-ray versus CT in COVID-19: a propensity-matched database study.
BMJ Open
; 10(11): e042946, 2020 11 06.
Article
in English
| MEDLINE | ID: covidwho-913770
ABSTRACT
OBJECTIVES:
To identify the diagnostic accuracy of common imaging modalities, chest X-ray (CXR) and CT, for diagnosis of COVID-19 in the general emergency population in the UK and to find the association between imaging features and outcomes in these patients.DESIGN:
Retrospective analysis of electronic patient records.SETTING:
Tertiary academic health science centre and designated centre for high consequence infectious diseases in London, UK.PARTICIPANTS:
1198 patients who attended the emergency department with paired reverse transcriptase PCR (RT-PCR) swabs for SARS-CoV-2 and CXR between 16 March and 16 April 2020. MAIN OUTCOMEMEASURES:
Sensitivity and specificity of CXR and CT for diagnosis of COVID-19 using the British Society of Thoracic Imaging reporting templates. Reference standard was any RT-PCR positive naso-oropharyngeal swab within 30 days of attendance. ORs of CXR in association with vital signs, laboratory values and 30-day outcomes were calculated.RESULTS:
Sensitivity and specificity of CXR for COVID-19 diagnosis were 0.56 (95% CI 0.51 to 0.60) and 0.60 (95% CI 0.54 to 0.65), respectively. For CT scans, these were 0.85 (95% CI 0.79 to 0.90) and 0.50 (95% CI 0.41 to 0.60), respectively. This gave a statistically significant mean increase in sensitivity with CT of 29% (95% CI 19% to 38%, p<0.0001) compared with CXR. Specificity was not significantly different between the two modalities.CXR findings were not statistically significantly or clinically meaningfully associated with vital signs, laboratory parameters or 30-day outcomes.CONCLUSIONS:
CT has substantially improved diagnostic performance over CXR in COVID-19. CT should be strongly considered in the initial assessment for suspected COVID-19. This gives potential for increased sensitivity and considerably faster turnaround time, where capacity allows and balanced against excess radiation exposure risk.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Radiography, Thoracic
/
Tomography, X-Ray Computed
/
Emergency Service, Hospital
/
Propensity Score
/
SARS-CoV-2
/
COVID-19
/
Lung
Type of study:
Diagnostic study
/
Observational study
/
Prognostic study
Limits:
Female
/
Humans
/
Male
/
Middle aged
Language:
English
Journal:
BMJ Open
Year:
2020
Document Type:
Article
Affiliation country:
Bmjopen-2020-042946
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