# Longitudinal functional lung imaging in children with Post-COVID-19 syndrome

## TL;DR

This study investigates whether lung defects cause persistent symptoms in children after recovering from COVID-19.

## Contribution

The study introduces longitudinal functional lung imaging to assess Post-COVID-19 syndrome in children.

## Key findings

- Vaccinated children had lower baseline ventilation compared to those with PCS.
- Ventilation and perfusion matching improved over time in both recovered and PCS groups.
- Clinical symptoms decreased over six months, but no significant lung defects were found.

## Abstract

Respiratory distress and COVID-19-related symptoms persist as Post-COVID-19 syndrome (PCS) in a proportion of children and adolescents.

We aimed to determine whether ventilation or perfusion defects constitute a possible cause for PCS.

Mean ventilation was lower at baseline in vaccinated than in PCS (p=0.04) and V/Qmatchnon-defected increased from baseline to follow-up in vaccinated (p=0.03). In post-hoc comparison with historic data, V/Qmatchnon-defected improved in recovered (historic: 63.5±18.7%; baseline: 88.8±9.0%, p<0.0001; follow-up: 88.1±10.6%; p=0.0002) and PCS (historic: 57.3±19.5%; baseline: 86.1±7.6%, p<0.0001; follow-up: 86.6±7.7%, p=0.0110). Symptom load in PCS decreased from infection and baseline time points to 6-month follow-up. Laboratory assessments showed no differences.

Despite persisting clinical symptoms, PREFUL MRI demonstrates no significant difference between cohorts, not supporting the hypothesis of persisting defects of the lung as causative.

The online version contains supplementary material available at 10.1186/s40348-025-00216-x.