Diagnostic accuracy of X-ray versus CT in COVID-19: a propensity-matched database study

Abstract

ObjectivesTo 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.DesignRetrospective analysis of electronic patient records.SettingTertiary academic health science centre and designated centre for high consequence infectious diseases in London, UK.Participants1198 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 outcome measuresSensitivity 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.ResultsSensitivity 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.ConclusionsCT 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.

The Profile of the Obstetric Patients with SARS-CoV-2 Infection According to Country of Origin of the Publication: A Systematic Review of the Literature

“…It is of note that all Chinese and French patients were evaluated by CT scan as radiological tests. Borakati et al [ 78 ] studied the diagnostic accuracy of X-ray versus CT in COVID-19. Following these authors, the sensitivity and specificity of CXR for COVID-19 diagnosis were 0.56 and 0.60 and for CT scans, 0.85 and 0.50, respectively, concluding that CT has substantially improved diagnostic performance over CXR and CT should be strongly considered in the initial assessment for suspected COVID-19 [ 78 ].…”

“…Borakati et al [ 78 ] studied the diagnostic accuracy of X-ray versus CT in COVID-19. Following these authors, the sensitivity and specificity of CXR for COVID-19 diagnosis were 0.56 and 0.60 and for CT scans, 0.85 and 0.50, respectively, concluding that CT has substantially improved diagnostic performance over CXR and CT should be strongly considered in the initial assessment for suspected COVID-19 [ 78 ]. This could be due either for the higher availability to perform chest CT in the various countries previously commented, along with the novelty suffered by China, as they were the first to face a new and unknown disease, therefore precise radiological tests with higher diagnostic accuracy.…”

COVIDC: An expert system to diagnose COVID-19 and predict its severity using chest CT scans: Application in radiology

“…RT-PCR is currently the gold standard diagnostic practice to detect viral infection [ 8 ]. However, the standard confirmatory clinical RT-PCR test to detect COVID-19 is manual, complex, laborious, costly, and ineffective [ 9 , 10 ]. Moreover, the limited availability of test kits and domain experts further hamper the situation.…”

“…In the current framework, chest X-ray (CXR) and chest Computed Tomography (CCT) can also effectively be used to diagnose COVID-19 [ 11 , 12 ]. However, CCT due to 3D image and contrast dyes shows a significantly improved performance in COVID-19 diagnosis in comparison to simple 2D CXR [ 9 ]. In the meanwhile, CT scans of COVID-19 infected patients show diverse features and manual interpretation of these scans with subtle variations is quite challenging [ 13 ].…”

A Pictorial Review of the Role of Imaging in the Detection, Management, Histopathological Correlations, and Complications of COVID-19 Pneumonia

“…A recent meta-analysis by Kim et al [ 101 ] reported a pooled sensitivity for chest CT of 94%, with a pooled specificity of 37%. Compared with CXR, chest CT showed increased sensitivity for COVID-19 pneumonia, with improved diagnostic performance [ 102 ]. Borakati et al [ 102 ] reported no difference in specificity between the two modalities.…”