Accuracy of Lung Ultrasound in the Diagnosis of covid19 Pneumonia

Overview

Is Lung Ultrasound really useful in diagnosing COVID19? What can be the usefulness of the Lung Ultrasound in the COVID19 epidemic? In the current state of the art, Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of Lung Ultrasound in the diagnosis of COVID-19 are not yet known. Alveolar-interstitial lung diseases such as viral pneumonia and ARDS seems to have a specific ultrasound pattern that distinguishes them from bacterial pneumonia, preferentially represented by B lines, morphological irregularity of the pleural line, and small subpleural consolidations, but they could share these patterns with other pathologies, reducing specificity. In Italy, the Lung Ultrasound represents a consolidated method for the evaluation and management of all patients who come to the ER, and what we are sure of is its high sensitivity in identifying pathological patterns. Our preliminary data suggest that Lung Ultrasound is highly reliable not to include but to exclude the diagnosis of COVID-19 in patients with respiratory symptoms.

One of the first scientific papers published on the COVID-19 epidemic in China showed that patients still asymptomatic or paucisymptomatic, positive for SARS-CoV-2 on the RT-PCR test, presented chest CT images referring to parenchymal infiltrate with a prevalent appearance at ground-glass compatible with initial COVID-19 pneumonia. An ongoing study anticipates that the sensitivity of chest CT is higher than that of the RT-PCR molecular test for SARS-CoV-2 (performed on the pharyngeal swab or sputum) (50 out of 51, 98%, 95% CI: 90% -100% vs 36 out of 51, 71%, IC95%: 56% -83%) in the early diagnosis of COVID-19. Recent work seems to shows that Lung Ultrasound is effective in the clinical evaluation and diagnosis of COVID-19 pneumonia. In a previous study, in addition, sensitivity and specificity of the Lung Ultrasound in the early diagnosis of H1N1 flu pneumonia was 94.1% (32 out of 34) and 84.8% respectively (28 out of 33), with a positive predictive value of 86.5% (32 out of 37) and a negative predictive value of 93.3% (28 out of 30). The concordance between the lung ultrasound findings and the lung lesions found on CT has recently been demonstrated ("lobe-specific" concordance equal to 87%; "lung-specific concordance" equal to 92.5 % for the right lung and 83.6% for the left lung). These data suggest to better explore the diagnostic accuracy of the Lung Ultrasound in SARS-CoV-2 infection.