Lung Ultrasound in COVID-19 Pneumonia: Correlations with Chest CT on Hospital admission

Abstract

Background: Lung ultrasound (LUS) is an accurate, safe, and cheap tool assisting in the diagnosis of several acute respiratory diseases. The diagnostic value of LUS in the workup of coronavirus disease-19 (COVID-19) in the hospital setting is still uncertain.

Objectives: The aim of this observational study was to explore correlations of the LUS appearance of COVID-19-related pneumonia with CT findings.

Methods: Twenty-six patients (14 males, age 64 ± 16 years) urgently hospitalized for COVID-19 pneumonia, who underwent chest CT and bedside LUS on the day of admission, were enrolled in this observational study. CT images were reviewed by expert chest radiologists, who calculated a visual CT score based on extension and distribution of ground-glass opacities and consolidations. LUS was performed by clinicians with certified competency in thoracic ultrasonography, blind to CT findings, following a systematic approach recommended by ultrasound guidelines. LUS score was calculated according to presence, distribution, and severity of abnormalities.

Results: All participants had CT findings suggestive of bilateral COVID-19 pneumonia, with an average visual scoring of 43 ± 24%. LUS identified 4 different possible -abnormalities, with bilateral distribution (average LUS score 15 ± 5): focal areas of nonconfluent B lines, diffuse confluent B lines, small subpleural microconsolidations with pleural line irregularities, and large parenchymal consolidations with air bronchograms. LUS score was significantly correlated with CT visual scoring (r = 0.65, p < 0.001) and oxygen saturation in room air (r = -0.66, p < 0.001).

Conclusion: When integrated with clinical data, LUS could represent a valid diagnostic aid in patients with suspect COVID-19 pneumonia, which reflects CT findings.

Keywords: Chest ultrasound; Coronavirus pneumonia; Point-of-care ultrasonography; SARS-CoV-2; Thoracic ultrasound.

Fig. 1

Appearance of COVID-19-related alveolar-interstitial pneumonia at bedside lung ultrasound. a Nonconfluent B lines (comet-tail artifacts) with spared areas of normal lung parenchyma showing A lines (horizontal artifacts). b Confluent B lines with “white lung” pattern and spared areas of normal lung parenchyma showing A lines. c Diffuse, nonconfluent B lines reflecting homogeneous interstitial involvement of lung parenchyma. d Subpleural microconsolidations with indentation of pleural line, associated with a nonconfluent focal B-line pattern. e Overt subpleural consolidation with air bronchograms. f Spared area showing A lines corresponding to a region of normally ventilated lung parenchyma without alveolar-interstitial involvement.

Fig. 2

Spearman correlation between lung ultrasound (LUS) score and CT visual scoring (a). The CT visual score was significantly different (p = 0.016) between patients with LUS score below and above the median value (b). The LUS score was also significantly different (p = 0.005) in patients who exhibited consolidation and/or diffuse ground-glass opacities (GGO) at chest CT versus those who had a patchy GGO pattern (c).