Quantitative ultrasound inflammation biomarker on a COVID-19 cohort

The aim of the current work was to quantify the red blood cells (RBCs) aggregate size in Covid-19 positive patients at risk of developing vascular thrombosis and compare results with control subjects. For this purpose, the current work relied on the effective medium theory combined with the structure factor model that was proposed for RBCs aggregate size estimation. Ten Covid-19 positive patients and twelve control subjects underwent superficial femoral vein and artery imaging sessions. Ultrasound acquisitions consisted in beamformed I&Q frames for each vessel. Backscatter coefficients (BSCs) were computed with the reference phantom method. The EMTSFM was then applied on BSCs yielding an estimation of the RBCs aggregate size (used as a biomarker), and its ancillary aggregate compactness, whilst the theoretical total attenuation, which is based on published values for dermis, muscles and blood, was refined. Increased RBCs aggregate sizes were observed in virus infected Covid-19 patients in comparison with control subjects. The mean aggregate size over the region of interest within vessel exhibited a statistically significant difference between Covid-19 patients and control subjects for veins (p= 0.0279) and arteries (p=0.0252), based on the rank sum test.