Application Value of Lung Ultrasound in Asymptomatic Patients with Confirmed COVID-19

To investigate the value of lung ultrasound (LUS) in asymptomatic patients with confirmed COVID-19.

A retrospective analysis was performed on nine patients in a designated isolation hospital in Sanya from February 22nd, 2020 to February 23rd, 2020. All patients were confirmed with COVID-19 pneumonia by PCR test, but none had the typical symptoms of COVID-19. All patients first underwent LUS examination and then chest computed tomography (CT) scanning. The application value of LUS in asymptomatic confirmed patients with COVID-19 was evaluated, compared with chest CT which was regarded as the golden standard.

Among nine asymptomatic patients with COVID-19, there were two cases (22.22%) with abnormal ultrasonic manifestations, of which one (11.11%) showed a fusion B3-line in zone 5 of the right lung, and the other showed localized pulmonary consolidation in zone 6 of the left lung. The remaining seven cases (77.78%) showed no abnormal changes in LUS, but only clear pleura sliding sign and A-line. Chest CT showed abnormal changes in three cases (33.33%). Two of them (22.22%) showed flocculent high-density shadow at the base of both lungs (especially in the right lung), while the other case showed ground-glass opacity with thickened interlobular septal in the left lower lobe, involving the pleura. There were no abnormalities on chest CT of the remaining six cases (66.67%). The two (22.22%) LUS-positive patients were in complete coincidence with CT-positive patients. This study showed that the coincidence rate of the two examination methods was 88.89%. Taking chest CT as golden standard, the sensitivity, specificity, positive predictive value, negative predictive value, and Kappa value of lung ultrasound in the diagnosis of COVID-19 were 66.67%, 100%, 100%, 85.71%, and 0.727, respectively.

LUS can evaluate lung lesions in asymptomatic patients with COVID-19. Compared with chest CT, the diagnostic coincidence rate and diagnostic consistency of LUS are relatively higher. For this asymptomatic type of patient, ultrasound can be used as a diagnosis method, which can avoid the risk of radiation exposure in a short period of time. As a rapid and dynamic assessment method, LUS can cooperate with remote consultation to provide timely and accurate guidance for clinical diagnosis and treatment when necessary.