Systemic Immune Response Syndrome After COVID-19 Immunization—Initial and Follow-up 18F-FDG PET/CT Imaging Appearances

Abstract

A 46-year-old woman with previous history of breast cancer had follow-up 18 F-FDG PET/CT 5 days after COVID-19 vaccination. In addition to avid axillary nodes, a well-documented feature, the scan demonstrated diffuse splenic and marrow uptake. Clinical history, laboratory, and scan findings were in keeping with SIRS (systemic inflammatory response). The patient recovered with supportive management. On follow-up, 18 F-FDG PET/CT imaging 3 months later features had resolved. SIRS after vaccination may be observed on 18 F-FDG PET/CT.

COVID-19 vaccination, implications for PET/CT image interpretation and future perspectives

“…Although exceptional cases of diseases occurred or worsened apparently after COVID-19 vaccination have been described in PET/ CT literature [19][20][21][22][23][24][25][26][27][28][29][30][31][32], none of the included studies reported findings suggestive for systemic reaction. The only exception was the study of Siripongsatian et al [18] who specifically evaluated a small series of patients who experienced neurological symptoms after COVID-19 vaccination. All types of COVID-19 vaccine, boosting a protective immune response through the production of neutralizing antibodies targeting SARS-CoV-2 spike S membrane glycoprotein [33], safely and positively impact on individual and global health, reducing the risk of severe infections.…”

“…Positive lymph nodes were observed less frequently in elderly (≥ 64 years) patients, and although after the second injection a second peak of incidence was observed in great elders (≥ 85 years), this datum should be carefully interpreted due to the small sample size. After the second injection, [ 18 and larger than after the first administration with a higher percentage of grades 3 (14 and 8%, respectively) and 4 (13 and 4%, respectively). Skawran et al [9] compared the inflammatory reaction observed after Pfizer-BioNTech and Moderna vaccinations in patients examined with [ 18 F]FDG PET/CT.…”

“…[ 18 F]FDG uptake in lymph nodes was graded by using the 5-point scale according to the Deauville criteria. A score higher than 2 was considered reactive.…”

“…Siripongsatian et al [18] reported preliminary data on patients who experienced neurological symptoms (e.g., headache, nausea, dizziness/drowsiness, paresthesia) after COVID-19 vaccination. Brain perfusion and metabolism were assessed at baseline (i.e., during symptoms) and within 1 week (i.e., control) through [ 15 O]Water PET and [ 18 F] FDG PET/MRI.…”

“…]FDG PET is an imaging method with growing interest for the diagnosis of sarcoidosis. In a recent metanalysis, [18 F]FDG PET/CT has been demonstrated to have a specificity similar to cardiac MRI in diagnosing cardiac sarcoidosis, although with a lower sensitivity [55]. Several studies assessed the role of [ 18 F]FDG PET/CT in the diagnosis of large-vessel vasculitis and in monitoring the disease's activity.…”