Time-related aortic inflammatory response, as assessed with 18F-FDG PET/CT, in patients hospitalized with severely or critical COVID-19

ABSTRACT

Aim: Arterial involvement has been implicated in the coronavirus disease of 2019 (COVID-19). Fluorine 18-fluorodeoxyglucose positron emission tomography/ computed tomography (18F-FDG PET/CT) imaging is a valuable tool for the assessment of aortic inflammation and is a predictor of outcome. We sought to prospectively assess the presence of aortic inflammation and its time-dependent trend in patients with COVID-19. Method(s) Between November 2020 and May 2021, in this pilot, casecontrol study, we recruited 20 patients with severe or critical COVID-19 (mean age of 59+/-12 years), while 10 age and sex-matched individuals served as the control group. Aortic inflammation was assessed by measuring 18F-FDG uptake in PET/CT performed 20-120 days post-admission. Global aortic target to background ratio (GLA-TBR) was calculated as the sum of TBRs of ascending and descending aorta, aortic arch, and abdominal aorta divided by 4. Index aortic segment TBR (IAS-TBR) was designated as the aortic segment with the highest TBR. Result(s) There was no significant difference in aortic 18F-FDG PET/CT uptake between patients and controls (GLA-TBR 1.46 [1.40-1.57] vs. 1.43 [1.32-1.70], respectively, p=0.422 and IAS-TBR 1.60 [1.50-1.67] vs. 1.50 [1.42-1.61], respectively, p=0.155). There was a moderate correlation between aortic TBR values (both GLA and IAS) and time distance from admission to 18F-FDG PET-CT scan (Spearman's rho=-0.528, p=0.017 and Spearman's rho=-0.480, p=0.032, respectively), Figure 1. Patients who were scanned less than or equal to 60 days from admission (n=11) had significantly higher GLA-TBR values compared to patients that were examined more than 60 days post-admission (GLA-TBR 1.53 [1.42-1.60] vs. 1.40 [1.33-1.45], respectively, p=0.016 and IAS-TBR 1.64 [1.51-1.74] vs. 1.52 [1.46-1.60], respectively, p=0.038). There was a significant difference in IAS-TBR between patients scanned <=60 days and controls (1.64 [1.51-1.74] vs. 1.50 [1.41-1.61], p=0.036), Figure 2. Conclusion(s) This is the first study suggesting that aortic inflammation, as assessed by 18F-FDG PET/CT imaging, is increased in the early post-COVID phase in patients with severe or critical COVID-19 and largely resolves over time. Our findings may have important implications for the understanding of the course of the disease and for improving our preventive and therapeutic strategies.