Magnetic resonance imaging (MRI) reveals lung damage in nonhospitalized children and teens who either had COVID-19 up to a year earlier or have long-COVID symptoms, according to a single-center clinical trial published this week in Radiology.
Researchers in Germany evaluated changes in lung structure and function in 54 pediatric COVID-19 survivors and nine healthy controls aged 5 to 17 years using low-field MRI, which doesn’t require children to hold their breath during imaging. Participants also contributed blood samples. The study was conducted from August to December 2021.
Signs of decreased lung function
Twenty-nine patients (54%) had recovered from their infections, 25 (46%) had long COVID, and all but one were unvaccinated at the time of infection. Four COVID-19 patients had asymptomatic acute infections. The median interval between infection and study participation was 222 days.
Average patient age was 11 years, and 44% were girls. Underlying medical conditions were identified in 22% of controls, 5% of recovered patients, and 10% of those with long COVID. The most common symptoms during the study were shortness of breath, impaired attention, headache, fatigue, and loss of smell.
The researchers measured the V/Q (ventilation/perfusion) match, an indicator of pulmonary air and blood flow. Ventilation refers to airflow into and out of the air sacs (alveoli) in the lungs, while perfusion is the blood flow to the tiny blood vessels in the alveoli.
If the lungs are working as they should, the air and blood flow match. But the V/Q match was only 62% in the recovered group and 60% in those with long COVID, compared with 81% in controls. The V/Q match was lower in COVID-19 patients infected less than 180 days (63%), 180 to 360 days (63%), and 360 days earlier (41%) than in controls (81%).
The ventilation defect percentage (VDP, which indicates the proportion of lung involvement) was lower in controls (13%) than in the recovered (22%) or long-COVID group (25%) after sorting COVID-19 patients by clinical characteristics. Similarly, the perfusion defect percentage (QDP) was higher in recovered patients (19%) and in those with long COVID (22%) than in controls (6.5%).
Combined V/Q defects were lower in controls (0.5%) than in the recovered (3.9%) and long-COVID participants (5.4%). After sorting participants by time since infection, measures of ventilation, perfusion, and combined defects all increased.
An unpredictable ‘diagnostic odyssey’
“Persistent symptoms after COVID still cause diagnostic odysseys, and this is especially true for young people,” Ferdinand Knieling, MD, of University Hospital Erlangen, said in a Radiological Society of North America news release. “Our findings illustrate that caring for these patients is a multidisciplinary challenge.”
The researchers said that, in contrast to previous studies based on surveys or self-reported outcomes, which have suggested that COVID-19 infections and long-term effects in children and adolescents are milder than in adults, “Our study demonstrates widespread functional lung alterations are indeed present in children and adolescents,” they wrote. “As children develop a robust, cross-reactive, and sustained immune response after SARS-CoV-2 infection, the observed pulmonary dysfunction in our study is an unexpected finding.”
The researchers said that the COVID-19–associated direct damage to the lining of blood vessels, inflammation, and blood clot-promoting environment may factor into the observed lung changes. The findings, they said, warrant heightened vigilance for persistent lung damage in the post-COVID pediatric population.
“Given the already existing diagnostic value of lung MRI and the translatability of the technology, these imaging approaches can be rapidly adopted to clinical routine care,” they concluded.