[18F]FDG uptake in axillary lymph nodes and deltoid muscle after COVID-19 mRNA vaccination: a cohort study to determine incidence and contributing factors using a multivariate analysis

Abstract

Purpose Reactive FDG uptake in the axillary lymph nodes (ALN) and deltoid muscle (DM) after COVID-19 mRNA vaccination has been recognized, although the actual situation in the Japanese population remains unknown. To determine the incidence of reactive FDG uptake and its contributing factors, we retrospectively studied a cohort of subjects who were vaccinated at our hospital. Methods Whole-body FDG-PET/CT examinations performed in 237 subjects out of 240 subjects with a definite history of COVID-19 vaccination (BNT162b2; BioNTech-Pfizer) were analyzed. Positivity and SUVmax of FDG uptake in the ALN and DM ipsilateral to vaccination, various subject characteristics, and the grade of the pathological FDG-PET/CT findings were evaluated using a multivariate analysis. Results FDG uptake in the ALN and DM ipsilateral to vaccination was seen in about 60% of the subjects even soon (0–4 days) after the first vaccination, with percentages reaching 87.5% and 75.0%, respectively, after the second vaccination. DM uptake had almost disappeared at around 2 weeks, while ALN uptake persisted for 3 weeks or longer. A multivariate analysis showed that a short duration since vaccination, a younger age, a female sex, and a low FDG-PET/CT grade (minimal pathological FDG uptake) contributed significantly to positive ALN uptake, while a short duration since vaccination and a female sex were the only significant contributors to positive DM uptake. This study is the first to identify factors contributing to positive FDG uptake in ALN and DM after COVID-19 vaccination. Conclusion A high incidence of FDG uptake in ALN and DM was observed after vaccination. ALN uptake seemed to be associated with a younger age, a female sex, and minimal pathological FDG uptake. After vaccination, an acute inflammatory reaction in DM followed by immune reaction in ALN linked to humoral immunity may be speculated.

The Clinical Utility of Molecular Imaging in COVID-19: An Update

“…The SUVmax of FDG-avid ALN and DM after the second vaccination was 4.79 ± 4.91 and 2.17 ± 1.02, respectively. 42 Cohen et al reported an incidence of hypermetabolic nodes in 36 % of patients following their first vaccine dose versus 54 % of patients following their second booster dose of an mRNA vaccine. Median SUVmax was 2.63, with high grade vaccine-associated FDG uptake (SUV max ≥ 4 in enlarged nodes) reported in 10 % of patients.…”

What Should We Do after the COVID-19 Vaccination? Vaccine-Associated Diseases and Precautionary Measures against Adverse Reactions

“…Abnormal menstrual cycles (delayed menstruation or increased bleeding or pain) [106], anaphylaxis [44], gout flares [48], lymphadenopathy [107,108], rhabdomyolysis [109], shoulder injuries related to vaccine administration (SIRVA) [109,110], and Vogt-Koyanagi-Harada syndrome [19] have also been reported following COVID-19 vaccination (Table 1). SIRVA is an acute inflammation of the shoulder that causes substantial shoulder pain and a limited range of motion [109,110].…”

“…SIRVA is an acute inflammation of the shoulder that causes substantial shoulder pain and a limited range of motion [109,110]. FDG uptake with positron emission tomography imaging, which suggests the inflammation of the deltoid muscle and axillary lymph nodes at the inoculation site, has been reported [107,108].…”

Atlas of non-pathological solitary or asymmetrical skeletal muscle uptake in [18F]FDG-PET

“…During labored breathing, the sternocleidomastoid and scalene are also used for inspiration, and the abdominal muscles are used for expiration. In addition, the site of [ 18 F]FDG injection [ 10 , 11 ] or recent vaccination history [ 12 ] should be considered when evaluating the upper extremities. Vascular inflammation and metal artifacts from cardiac implantable devices also interrupt evaluation in the chest area [ 6 , 7 ].…”

“…Therefore, it would be important to understand the pattern of this muscle. Three cases with unilateral uptake (a, b) and bilateral uptake (c) of the obliquus capitis inferior muscle (arrows) are shown vaccination history [12] should be considered when evaluating the upper extremities. Vascular inflammation and metal artifacts from cardiac implantable devices also interrupt evaluation in the chest area [6,7].…”