Chest imaging in the diagnosis of COVID-19: fairly sensitive, but insufficiently specific
Cochrane Pre-hospital and Emergency Care
Chest imaging in the diagnosis of COVID-19: fairly sensitive, but insufficiently specific!
Islam_N, Ebrahimzadeh_S, Salameh_J-P, Kazi_S, Fabiano_N, Treanor L et al (2022)
Thoracic imaging tests for the diagnosis of COVID-19.
Cochrane Database Syst Rev, 5, CD013639.
CONTEXT
COVID-19 presents a diagnostic challenge with reverse transcription polymerase chain reaction (RT-PCR) tests having limitations. The potential contribution of additional thoracic imaging is unclear.
CLINICAL QUESTION
What is the diagnostic accuracy of chest imaging studies (CT, X-ray, ultrasound) in patients of any age suspected of having COVID-19?
BOTTOM LINE
Nearly 38,000 patients were included, 53% of whom were found to have COVID-19. All studies used at least one RT-PCR test as a reference for the diagnosis of COVID-19.
For radiographic evaluation, the sensitivity and specificity were 73.1% and 73.3%, respectively.
For ultrasound evaluation, the sensitivity and specificity are 88.9 % and 72.2% respectively.
For CT evaluation, the sensitivity was 86.9% and specificity 78.3%. Eleven studies used a precise classification system, the COVID-19 Reporting and Data system (CO-RADS), which has 5 thresholds to define the positivity of the test (from unlikely (1) to highly suggestive (5)). With a CO-RADS threshold of 5 for CT evaluation, the sensitivity was 67.3% and the specificity was 92.2%.
Moreover, since the beginning of this health crisis, there has been a significant increase in the specificity of the CT assessment while the sensitivity remained stable.
In an indirect comparison of the imaging tests with each other, CT and ultrasound were sensitive and moderately specific in the diagnosis of COVID-19. Radiography is moderately sensitive and specific in the diagnosis of COVID-19.
CAVEAT
Chest CT and chest ultrasound may be more useful in ruling out COVID-19 than in differentiating SARS-CoV-2 infection from other causes of respiratory disease. Because of the heterogeneity between studies (methodology, inclusion criteria), the confidence in the results should be limited. Additional studies are needed to establish more reliable results, particularly considering the time of evolution of COVID-19 and the symptomatology presented.
AUTHORS
S. Beroud
Urgences & SAMU de Lyon, Hôpital Lyon Sud
F-69394 Lyon, France
N. Nekhili
SMUR, centre hospitalier de Gonesse,
F-95500 Gonesse, France
K. Magee
Kirk.magee@dal.ca
Dalhousie University, Halifax Infirmary
Nova Scotia, Canada
