Lung Ultrasound Findings in COVID-19
The most common lung ultrasound (LUS) findings in screened studies and
their relative prevalence were irregular pleural lines (27.9 to 89% in
patients), pleural thickening (6.5 to 86%), separate “distinct or
scattered” B-lines (16.6 to 88%), confluent “coalescent” B-lines
with or without “white lung” (12 to 78.6%), pulmonary consolidations
(31.1 to 77%), sub-pleural consolidations (8.06 to 73%) and pleural
effusions (3.8% to 56%)[74–82] [Table 2] .
Variability in prevalence of LUS findings is likely related to
heterogeneity in the severity of the disease, as well as the timing of
LUS in the course of the disease. For example, Mafort et al studied
symptomatic healthcare professionals who had a positive RT‐PCR test for
COVID‐19. They detected coalescent B‐lines and subpleural consolidations
in 36% and 8.06% of patients, respectively. Bilateral involvement was
seen in only 50.1% of patients. Of note, they studied patients during
their first assessment and those hospitalized or undergoing intensive
care were not included[76].
With regards to the distribution of LUS, bilateral distribution was
noted in 50.1 to 100% of cases. A greater tendency to involve the
posterior and lateral regions with less involvement of the anterior
region was demonstrated by Smargiassi A et al [83]. Using a specific
scoring system ranging from 0 to 3 (worst score, 3), they were able to
demonstrate a higher prevalence of score 3 in posterior and lateral
regions, and a higher prevalence of score 0 in the anterior regions in a
population of non-critically ill patients. A more prominent involvement
of the posterior and lower regions was also noted by Castelao J et al in
95.5% and 73.8% of studied patients, respectively[84]. Similar
predilection for posterior and lower region involvement was described by
Lu W et al, who also noted a subpleural and peripheral pulmonary zones
distribution of LUS findings[78]. Interestingly, a more prominent
involvement of the anterior areas of the lungs was noted in patients
with severe disease relative to those with mild disease (36% vs 21% of
patients, p .021)[85], and clinical deterioration was associated
with loss of aeriation in anterior lung segments[86].