Recognising and interpreting reactive changes due to COVID-19 vaccinations: A multi-modality pictorial series

Abstract

Category: OtherOutline of submission:In order to combat the spread of novel coronavirus disease, many countries have started mass immunisation programmes. In the UK, the first vaccine was administered on 8 December 2020. Some vaccinations are known to cause transient inflammation and avidity on 18F-fluorodeoxyglucose positron emission tomography (18 F-FDG PET/CT). COVID-19 vaccination also causes ipsilateral reactive lymphadenopathy. This can pose a diagnostic challenge in imaging. It is important for radiologists and nuclear medicine physicians to consider vaccination in the differential diagnosis of such cases to avoid misinterpretation. Recording of recent vaccinations in patient documentations is important to aid appropriate interpretation. Guidelines on management of axillary nodes may need adopting to include findings of vaccination-related changes.Educational objectives:•To present ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), FDG and 68Ga DOTATATE PET-CT pictorial examples of the spectrum and pattern of reactive nodes and tracer uptake that are seen in recently COVID-19 vaccinated individuals.•To discuss features of reactive lymph nodes (eg normal size and morphology in a ipsilateral tracer avid node).•To highlight the requirement for patient vaccination history to be recorded and available at the time of reporting.•Suggestions on follow up in equivocal cases. Category: Other Outline of submission: In order to combat the spread of novel coronavirus disease, many countries have started mass immunisation programmes. In the UK, the first vaccine was administered on 8 December 2020. Some vaccinations are known to cause transient inflammation and avidity on 18F-fluorodeoxyglucose positron emission tomography (18 F-FDG PET/CT). COVID-19 vaccination also causes ipsilateral reactive lymphadenopathy. This can pose a diagnostic challenge in imaging. It is important for radiologists and nuclear medicine physicians to consider vaccination in the differential diagnosis of such cases to avoid misinterpretation. Recording of recent vaccinations in patient documentations is important to aid appropriate interpretation. Guidelines on management of axillary nodes may need adopting to include findings of vaccination-related changes. Educational objectives:•To present ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), FDG and 68Ga DOTATATE PET-CT pictorial examples of the spectrum and pattern of reactive nodes and tracer uptake that are seen in recently COVID-19 vaccinated individuals.•To discuss features of reactive lymph nodes (eg normal size and morphology in a ipsilateral tracer avid node).•To highlight the requirement for patient vaccination history to be recorded and available at the time of reporting.•Suggestions on follow up in equivocal cases.