Abstract
PurposeThe study’s aim is to analyse the diagnostic performance of chest radiography (CXR) in patients with suspected coronavirus disease 19 (COVID-19).MethodsWe retrospectively considered 826 consecutive patients with suspected COVID-19 presenting to our emergency department (ED) from February 21 to March 31, 2020, in a high disease prevalence setting. We enrolled patients who underwent CXR and rhino-oropharyngeal swab for real-time reverse transcription-polymerase chain reaction (rRT-PCR). CXRs were evaluated by an expert radiologist; a second independent analysis was performed by two residents in consensus. All readers, blinded to rRT-PCR results, classified CXRs positive/negative depending on presence/absence of typical findings of COVID-19, using rRT-PCR as reference standard.ResultsWe finally analysed 680 patients (median age 58); 547 (80%) tested positive for COVID-19. The diagnostic performance of CXR, interpreted by the expert reader, was as follows: sensitivity (79.0%; 95% CI: 75.3–82.3), specificity (81.2%; 95% CI: 73.5–87.5), PPV (94.5%;95% CI: 92.0–96.4), NPV (48.4%; 95% CI: 41.7–55.2), and accuracy (79.3%; 95% CI: 76.0–82.2). For the residents: sensitivity (75.1%; 95% CI: 71.2–78.7), specificity (57.9%; 95% CI: 49.9–66.4), PPV (88.0%; 95% CI: 84.7–90.8), NPV (36.2%; 95% CI: 29.7–43.0), and accuracy (71.6%; 95% CI: 68.1–75.0). We found a significant difference between the reporting sensitivity (p = 0.013) and specificity (p < 0.0001) of expert radiologist vs residents. CXR sensitivity was higher in patients with symptom onset > 5 days before ED presentation compared to ≤ 5 days (84.4% vs 70.7%).ConclusionsCXR showed a sensitivity of 79% and a specificity of 81% in diagnosing viral pneumonia in symptomatic patients with clinical suspicion of COVID-19. Further studies in lower prevalence settings are needed.
Highlights
CXR showed a sensitivity of 79% and a specificity of 81% in diagnosing viral pneumonia in symptomatic patients with clinical suspicion of COVID-19
We considered eligible for inclusion a consecutive series of patients who presented to the emergency department (ED) of our hospital between February 21 and March 31, 2020, with clinical and epidemiological data raising suspicion of COVID-19
Out of the 826 consecutive patients who presented to the ED of our hospital between February 21 and March 31, 2020, 734 (89%) were clinically suspected of having COVID-19 and 680 were included in our analysis
Summary
In the year 2020, the world has seen a steady increase in the number of coronavirus disease 2019 (COVID-19) cases, an infectious disease caused by the recently discovered respiratory pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with over 107 million confirmed cases and over 2.3 million deaths as of February 12, 2021 [1].Because of the high number of cases, especially during peaks of incidence, managing the emergency has proved challenging in many countries.Adequate management of the emergency, especially in a setting of high disease prevalence, requires early diagnosis in order to control the spread of the infection, isolating infected patients (either at home or in hospital), and to avoid ED congestion.The reference standard test for the diagnosis of SARSCoV-2 infection is real-time reverse transcriptionpolymerase chain reaction (rRT-PCR) on rhinooropharyngeal swab samples; the laboratory procedure is time-consuming and may become a rate-limiting step if there is an increase in demand; it has a moderate sensitivity, ranging from 60 to 70% [2, 3].In this context, chest imaging has played an important role in the diagnostic work-up of patients with suspected COVID19, in association with clinical and laboratory data; it has been helpful in settings where rRT- PCR results were not readily available or in case of discrepancies between negative rRT-PCR results and clinical data [4].Most radiological papers published since the beginning of this pandemic have focused on chest CT, which has shown the highest sensitivity among medical imaging modalities, despite a low specificity [2, 5,6,7]. The reference standard test for the diagnosis of SARSCoV-2 infection is real-time reverse transcriptionpolymerase chain reaction (rRT-PCR) on rhinooropharyngeal swab samples; the laboratory procedure is time-consuming and may become a rate-limiting step if there is an increase in demand; it has a moderate sensitivity, ranging from 60 to 70% [2, 3] In this context, chest imaging has played an important role in the diagnostic work-up of patients with suspected COVID19, in association with clinical and laboratory data; it has been helpful in settings where rRT- PCR results were not readily available or in case of discrepancies between negative rRT-PCR results and clinical data [4]. European and US imaging societies have issued statements advising against a routine use of CT scan as a screening tool [8, 9]; at ED, chest radiography (CXR) and lung ultrasound (LUS) [10] represent alternative imaging modalities with significant advantages, such as lower radiation doses, lower risk of contamination, lower costs, and more widespread availability
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