Imaging Characteristics of Vaccine-Associated Lymphadenopathy

Vaccine-associated lymphadenopathy encompasses transient enlargement and functional alteration of regional lymph nodes following immunisation. On imaging, these nodes often demonstrate cortical thickening, increased vascularity and, in the case of metabolic studies, elevated tracer uptake. Modalities including ultrasound, magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) have been used to characterise these changes, which may mimic malignant involvement. Distinguishing benign reactive nodes from metastatic or neoplastic nodes is critical to avoid unnecessary interventions. Global datasets from the past two years have refined the criteria for benign classification, proposed follow-up intervals, and explored correlations between nodal morphology and vaccine-induced immune responses. Practical applications span oncology, breast imaging and specialised oncology surveillance, underscoring the need for standardised reporting systems and clear thresholds for biopsy versus observation.

Research from Nature Portfolio

An adapted Node Reporting and Data System, termed A-Node-RADS, has been developed to stratify axillary lymph nodes on low-dose CT images in patients undergoing PET/CT after vaccination. In a cohort of melanoma patients, this classification achieved very high concordance with a combined reference standard, successfully distinguishing normal, reactive and metastatic nodes. The system assigns benign, equivocal or malignant categories based on nodal size, shape and anatomical features, providing an objective tool to guide clinical decision-making in the context of vaccine-induced hypermetabolism.

Imaging Characteristics of Vaccine-Associated Lymphadenopathy publication trend

The graph below shows the total number of articles in imaging characteristics of vaccine-associated lymphadenopathy across all publications each year (not limited to Nature Index journals).

Technical terms

Lymphadenopathy: Enlargement or altered morphology of lymph nodes, often reflecting immune activation.

Cortical thickness: Measurement of the outer lymph node cortex on ultrasound, with increased values indicating hyperplasia.

[18F]-FDG PET/CT: Hybrid imaging combining fluorodeoxyglucose uptake assessment with CT anatomy to evaluate metabolic activity within tissues.

A-Node-RADS: Adapted Node Reporting and Data System classification for standardising lymph node assessment on CT in vaccinated patients.

BI-RADS: Breast Imaging Reporting and Data System, a risk-stratification framework for breast lesions to guide management.

References

1. Characterization of hypermetabolic lymph nodes after SARS-CoV-2 vaccination using PET-CT derived node-RADS, in patients with melanoma. Scientific Reports (2023).
2. Prediction of effective humoral response to SARS-CoV-2 vaccines in healthy subjects by cortical thickness of post-vaccination reactive lymphadenopathy. European Radiology (2023).
3. European Society of Breast Imaging (EUSOBI) guidelines on the management of axillary lymphadenopathy after COVID-19 vaccination: 2023 revision. Insights into Imaging (2023).
4. The location of unilateral axillary lymphadenopathy after COVID-19 vaccination compared with that of metastasis from breast cancer without vaccination. Japanese Journal of Radiology (2023).