21 Lung Ultrasound Versus Chest X-Ray for the Radiographic Diagnosis of COVID-19 Pneumonia in a High Prevalence Population

Abstract

collection were performed on days 3, 5, 7 or 12+/-1 day for admitted patients. All clips with 2 or more B-lines were included (N¼80), as well as a random selection of 70 clips with 1 or fewer B-lines. B-line count for inclusion was based on visual rating by two researchers with POCUS training. A POCUS fellowship trained emergency physician visually assessed each clip frame and counted the maximum number of B-lines per clip. This was compared to automatic counts by the commercially available Lumify TM Lung B-lines Quantification software by intraclass correlation coefficient (ICC) and Cohen's weighted kappa.Results: Of the 899 total clips,150 clips from 30 unique subjects and 44 overall exams were used for analysis, with 100 clips from patients with confirmed COVID by PCR. The average maximum B-line count by algorithm was 1.52 +/-1.24, and that by expert was 1.60 +/-1.35 (ns). The ICC between algorithm and expert was 0.87 (95% CI 0.83-0.91), with a weighted kappa of 0.64 (95% CI 0.48-0.81), indicating substantial agreement. Average of maximum B-line counts, ICC and weighted kappa between algorithm and expert were comparable for COVID+ and COVID-subgroups as well as between transducer types. For COVID + subgroup, the average of maximum B-line counts was 1.73 +/-1.28 for algorithm and 1.78 +/-1.37 for expert, with weighted kappa 0.67 (95% CI 0.50-0.84), and ICC 0.87 (95% CI 0.83 to 0.91).Conclusion: An automated algorithm developed on non-COVID patients can accurately distinguish and quantify B-lines in clips from patients with COVID-19, with substantial agreement to expert visual rating.