Lung ultrasound in early SARS-CoV-2 pneumonia and the LUS-CoV criteria

Abstract

There is a scarcity of data on lung ultrasound (LUS) in SARS-CoV-2 pneumonia. As with many other pulmonary conditions, ultrasound may be a better diagnostic tool than routine chest radiography. In an era where computed tomography scanning is deferred because of the potential for cross-contamination, we evaluated the ability of LUS to detect a pattern of lung injury in SARS-CoV-2 pneumonia. A limited anterolateral LUS was performed to limit time spent in isolation rooms by ultrasound operators. We chose to use a hand-held ultrasound device due to portability and superior confidence in infection control. Both linear and phased array probes were used to obtain images of the pleura and lung. Of 69 patients who had lung ultrasound images saved and were included in the analysis, 36 were positive for SARS-CoV-2. Multifocal confluent B-lines, pleural irregularities, and the absence of moderate or large pleural effusions were the predominant pattern observed in most (86%) of SARS-CoV-2-positive patients. We evaluated the accuracy of the above criteria (LUS-CoV) and report a high sensitivity (91%) and specificity (86%) for SARS-CoV-2 pneumonia. In conclusion, a characteristic sonographic pattern of multifocal confluent B-lines with irregular pleural markings was seen on LUS in patients with SARS-CoV-2 pneumonia.

Keywords: COVID-19; SARS-CoV-2; lung ultrasound.

Figure 1.

A summary of LUS findings represented by arrows, divided into phased array probe images in the top row and linear array probe images in the bottom row. (a) A-lines, repetitive equidistant horizontal artifacts. (b, e) Nonconfluent B-lines, discrete vertical comet-tail artifacts. (c, f) Confluent B-lines, dense vertical artifacts >5 m width at the pleural line by visual estimate. (d) Pleural effusion and costophrenic consolidation, with the hypoechoic area representing pleural fluid and punctate hyperechoic artifacts within consolidated lung representing airbronchograms. (g) Subpleural consolidation, small, well-defined hypoechoic areas immediately beneath the pleural line. (h) Pleural irregularities, loss of smooth contour of pleura or discontinuities of the pleural line.