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Functional respiratory imaging identifies redistribution of pulmonary blood flow in patients with COVID-19
  1. Muhunthan Thillai1,2,
  2. Chinmay Patvardhan1,
  3. Emilia M Swietlik1,2,
  4. Tom McLellan1,
  5. Jan De Backer3,
  6. Maarten Lanclus3,
  7. Wilfried De Backer3,
  8. Alessandro Ruggiero1
  1. 1 Royal Papworth Hospital, Cambridge, UK
  2. 2 Department of Medicine, University of Cambridge, Cambridge, Cambridgeshire, UK
  3. 3 Fluidda NV, Antwerp, Belgium
  1. Correspondence to Dr Muhunthan Thillai, Royal Papworth Hospital, Cambridge CB2 0AY, UK; muhunthan.thillai{at}


An increasing observation is that some patients with COVID-19 have normal lung compliance but significant hypoxaemia different from typical acute respiratory distress syndrome (ARDS). We hypothesised that changes in pulmonary blood distribution may be partially responsible and used functional respiratory imaging on CT scans to calculate pulmonary blood volume. We found that patients with COVID-19 had significantly reduced blood volume in the smaller calibre blood vessels (here defined as <5 mm2 cross-sectional area) compared with matched ARDS patients and healthy controls. This suggests that using high levels of PEEP may not alone be enough to oxygenate these patients and that additional management strategies may be needed.

  • critical care
  • ARDS
  • imaging/CT
  • MRI

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  • Contributors MT and AR devised the study. CP and TM collected data. JDB, MLL and WD performed the functional respiratory imaging analysis. MT, AR and EMS analysed the data and EMS performed the statistical analysis. All authors were involved in writing the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests JDB, MLL and WD are employees of Fluidda NV who performed the functional respiratory imaging analysis. MT and AR are directors of Qureight who performed the data analytics.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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