Longitudinal lung function assessment of patients hospitalised with COVID-19 using 1H and 129Xe lung MRI

Abstract

<b>Introduction:</b> The progression of pathophysiological pulmonary changes in patients following acute COVID-19 is not well established. <b>Methods:</b> Patients hospitalised with COVID-19 pneumonia without signs of ILD, had MRI&nbsp;exams at a median of 6 (n=9), 12 (n=9), 25 (n=7), and 52 (n=3) weeks. MRI&nbsp;sequences included: dynamic contrast enhanced (DCE) lung perfusion,&nbsp;¹²⁹Xe diffusion weighted (DW-MRI),^&nbsp;129Xe ventilation and&nbsp;¹²⁹Xe 3D dissolved phase imaging. <b>Results:</b> 9 patients (age 56±9 years; 7 male; 1 required treatment in an ICU) were recruited. Median RBC:TP was abnormally low at all visits compared to reference age and sex matched data. An individual’s RBC:TP was significantly and positively associated with an increase in their pulmonary blood volume (p=0.026). For patients with 52 week data available, one showed a continued increase in RBC:TP, 2 patients maintained a low RBC:TP (Figure 1). Ventilation defect percentage, and ventilation heterogeneity significantly decreased at 25 weeks compared to 6 weeks (p=0.010 and p=0.048).&nbsp;DW-MRI was normal at all visits. Dissolved phase xenon imaging showed RBC:TP significantly increased at&nbsp;12 and 25 weeks compared to 6 weeks (p=0.048). <b>Conclusions:</b> In patients recovering after COVID-19, poor gas transfer is reflected by impaired xenon transfer, which improves alongside pulmonary blood volume. <b>Figure 1:</b> White lines are reference age matched healthy volunteer median and IQR.