Activity of the spleen and bone marrow in relation to cardio-pulmonary injury in patients with acute covid-19 evaluated by 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging
Imaging and Diagnostic Radiology (East Africa)
Objective: COVID-19 primarily causes pneumonitis but can also cause myocarditis. Injury may be due to a generalised inflammatory immune process or by direct viral infection. Using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) and cardiac magnetic resonance (CMR) imaging we correlated the metabolic activity/injury between the reticuloendothelial system (bone marrow [BM] and spleen) and myocardial/pulmonary tissue.
Methods: 18F-FDG-PET/CT (n=29, fasted n=27) and CMR (n=23) were performed on hospitalised patients with acute COVID-19. 18F-FDG PET/CT standardised uptake values (SUV) were measured in the spleen, spinal BM, myocardial and pulmonary tissue. Cardiac target-to-background ratio (TBR) was calculated by indexing to blood-pool SUV. Myocarditis was assessed using the sensitive 2018 Lake Louise criteria (LLC), and viral load (by cycle threshold).
Results: 13 patients had myocarditis on CMR (57%), 8 (30%) visually on 18F-FDG-PET/CT. There was no statistical difference comparing LLC positive and negative patients for BM (4.21±0.30, 4.98±0.56, P=0.23), spleen (4.40±0.40, 5.15±0.08, P=0.38) and lung (4.08±0.72, 4.16±0.91, P=0.94) SUV. Lung SUV was significantly associated with BM (r=0.61, P0.05 for all). Cycle threshold did not correlate with either cardiac TBR and T1 or T2 (p>0.05 for all).
Conclusion: Reticuloendothelial system activation strongly correlated with lung activity, suggesting pulmonary injury is part of a systemic inflammatory process. Cardiac inflammation was not associated with either spleen, BM or viral load, suggesting injury is multifactorial.
Shah, A. S.,
(2022). Activity of the spleen and bone marrow in relation to cardio-pulmonary injury in patients with acute covid-19 evaluated by 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Heart, 108(2).
Available at: https://ecommons.aku.edu/eastafrica_fhs_mc_imaging_diagn_radiol/68