# Distribution and predictors of F-18-FDG uptake values of non-malignant cervical lymph nodes in pediatric patients

## TL;DR

This study identifies that the uptake of FDG in non-cancerous cervical lymph nodes in children is often higher than liver uptake, with the tonsil's uptake being a key predictor.

## Contribution

The study identifies the SUVmax of ipsilateral palatine tonsils as a strong predictor of FDG uptake in non-malignant cervical lymph nodes in pediatric patients.

## Key findings

- Ipsilateral palatine tonsil SUVmax is a significant predictor of SUVmax in non-malignant cervical lymph nodes.
- SUVmaxCLN was higher than liver uptake in 50% of all studies, increasing to 77% in children under six years.
- Increased FDG activity in cervical nodes was observed in 71% of the 191 pediatric studies analyzed.

## Abstract

F-18-flurodeoxyglucose (FDG) PET/CT is routinely used for staging, evaluation of response to treatment and follow-up of most pediatric malignancies. Cervical lymph nodes can be involved in some pediatric malignancies, but increased uptake in non-malignant cervical lymph nodes is not exceptional in this population. The aim of the present study is to identify predictors of the maximum uptake in non-malignant cervical lymph nodes in the pediatric population.

191 FDG PET/CT studies of pediatric patients without malignant involvement of cervical lymph nodes were retrospectively reviewed. The maximal Standard Uptake Value in the hottest cervical lymph node (SUVmaxCLN), as well as demographic, technical and imaging variables were recorded. The predictive effect of those variables on SUVmaxCLN was estimated using linear regression models.

Increased FDG activity in cervical nodes was observed in 136/191 studies (71%). The mean SUVmaxCLN was 2.2 ± 1.3. Ipsilateral palatine tonsil SUVmax, mean liver uptake, and treatment status were all statistically significant predictors of SUVmaxCLN. However, in multivariate regression analysis, only ipsilateral palatine tonsil SUVmax was found to be significant. In addition, SUVmaxCLN was greater than the mean liver uptake in 50% of all studies. This proportion was higher in younger children, reaching 77% of studies of children younger than six years.

SUVmax in ipsilateral palatine tonsil is a strong predictor of the maximal uptake value of non-malignant cervical lymph nodes in children. The intensity of uptake in non-malignant cervical lymph nodes is frequently higher than liver uptake in children, and this tendency increases for younger patients.

In the internal hospital registry under TRN 0209-22-HMO on date 23.04.2022.