Lung Ultrasound vs. Chest X-ray for the Radiographic Diagnosis of COVID-19 Pneumonia in a High Prevalence Population

Gibbons, Ryan C.; Magee, Mark; Goett, Harry; Murrett, James; Genninger, Jessica; Mendez, Kendra; Tripod, Matthew; Tyner, Nicholas; Costantino, Thomas G.

Background The viral illness severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more commonly known as coronavirus 2019 (COVID-19), has become a global pandemic, infecting over 100 million individuals worldwide. Objectives The objective of this study was to compare the test characteristics of point-of-care lung ultrasound (LUS) with chest x-ray (CXR) at radiographically detecting COVID-19 pneumonia. Methods This was a single-center, prospective, observational study at an urban university hospital with >105,000 patient visits annually. Patients >18 years old, who presented to the emergency department with predefined signs and symptoms of COVID-19, were eligible for enrollment. Each patient received a LUS using a portable, handheld ultrasound followed by a single view, portable anteroposterior CXR. Patients with an abnormal LUS or CXR underwent a non-contrast-enhanced computed tomography (NCCT). The primary outcome was the radiographic diagnosis of COVID-19 pneumonia on NCCT. Results 110 patients underwent LUS, CXR, and NCCT. 99 LUS and 73 CXRs were interpreted as positive. 81 NCCT were interpreted as positive providing a prevalence of COVID-19 pneumonia of 75% (95% CI 66-83.2) in our study population. LUS sensitivity was 97.6% (95% CI 91.6-99.7) vs 69.9% (95% CI 58.8-79.5) for CXR. LUS specificity was 33.3% (95% CI 16.5-54) vs 44.4% (95% CI 25.5-64.7) for CXR. LUS positive predictive value (PPV) and negative predictive value (NPV) were 81.8% (95% CI 72.8-88.9) and 81.8% (95% CI 48.2-97.7) vs. 79.5% (95% CI 68.4-88) and 32.4% (95% CI 18-49.8) for CXR. Conclusion LUS was more sensitive than CXR at radiographically identifying COVID-19 pneumonia.