Correlation between Remote Dielectric Sensing and Chest X-Ray to Assess Pulmonary Congestion

Background: Chest X-ray is a practical tool to semi-qualify pulmonary congestion. Remote dielectric sensing (ReDS) is a recently introduced, non-invasive, electromagnetic energy-based technology to quantify pulmonary congestion without expert technique. We compared these two modalities to clarify appropriate clinical situations for each modality. Methods: ReDS and chest X-ray measurements were prospectively performed on admission in consecutive hospitalized patients with cardiovascular diseases. In the chest X-ray, the congestive score index (CSI) was calculated blindly by two independent experts and averaged. CSIs were correlated with ReDS values. Results: A total of 458 patients (76 (69, 82) years old, 267 men, and 130 heart failure) were included. Median ReDS value was 28% (25%, 33%). There was a mild correlation between ReDS values and CSIs (r = 0.329, p < 0.001). The correlation between ReDS values and CSIs became stronger in the heart failure cohort (r = 0.538, p < 0.001). In patients with mild congestion (ReDS < 35%), ReDS values, instead of CSI, stratified the degree of congestion. In patients with severe congestion (ReDS > 35%), both modalities stratified the degree of congestion. Conclusions: Both chest X-ray and ReDS are useful for assessing severe pulmonary congestion, whereas ReDS would be preferred to chest X-ray in stratifying the severity of mild pulmonary congestion.