Evaluation of metabolic changes in FDG PET/CT imaging after mRNA-based COVID-19 vaccination.

BACKGROUND: It isimportant to evaluate the vaccine-related metabolic changes on FDG PET/CT to avoid confusing results. We here aimed to assess the frequency and intensity of regional and systemic metabolic PET/CT changes of patients who received the mRNAbased COVID-19 vaccine (BNT162b2-Pfizer/BioNTech) and to analyze possible factors affecting these changes. METHODS: Among the patients who underwent FDG PET/CT for any indication in our department between July 2021 and December 2021, 129 volunteer patients with a history of COVID-19 vaccination were included in this prospective observational study. Bilateral axillary lymph nodes, ipsilateral deltoid muscle, bone marrow, spleen, thyroid, and liver FDG uptakes were evaluated visually and semiquantitatively for each examination. RESULTS: The frequencies of positive axillary lymph nodes after vaccination were 40%, 44.4%, 32.6%, and 44.7% in all, 1st dose, 2nd dose, and heterologous vaccination regimens groups, respectively. Maximum standardized uptake values of spleen, liver, and bone marrow were statistically high in patients with positive axillary lymph nodes than with negative ones (p < 0.05). Positive deltoid muscle uptake and diffusely increased thyroid uptake findings were observed in 10 and 8 patients, respectively. The median time interval between vaccination and imaging was 9.5 days for patients with positive axillary lymph nodes and 17 days for patients with negative nodes. In our study group, only 8 patients had a positive documented history of COVID-19 infection. DISCUSSION: Regional and systemic metabolic changes were occasionally found on FDG PET/CT imaging in patients who received the mRNA-based COVID-19 vaccine. To avoid these timely decreasing changes, we recommend managing the ideal timing of imaging or vaccination and taking a careful history.

The role of negative entropy within supply chain sustainability.

With the COVID-19 pandemic, supply chains are today confronted with more uncertainties than ever before. In the face of unanticipated disruptions, being resilient and sustainable has been rewarding for supply chains in terms of competitive advantage. However, literature is still far from possessing an encompassing sustainable supply chain framework (SSCF). As a contribution to the extant literature, the present study expounds a prominent concept termed negative entropy and explores its role in the SSCF. To accomplish this goal, the effect of negative entropy on supply chain sustainability is tested. Following the open systems theory and drawing from the collaboration and information management aspects of the negative entropy, co-creation, open innovation and network governance concepts which are considered to be relevant in this context are selected to be the antecedents of negative entropy. The empirical research is conducted on prominent logistics service providers and firms from various sectors with approved research and development departments in Turkey. The obtained data were subjected to covariance-based structural equation modeling analysis via Lisrel program. According to results, negative entropy is found to be a robust element in explaining supply chain sustainability. Furthermore, whereas co-creation and network governance reflected significant effects on negative entropy, surprisingly, open innovation demonstrated no substantial impact. This paper opens up a new front in sustainable supply chain management studies with a notable empirical study introducing negative entropy in the context of open systems theory.