Unexpected Pulmonary dysfunction in children after recovery from COVID-19 and long COVID, reveals MRI study

Germany: According to a recent study published in the Radiology by the Radiological Society of North America, researchers of Germany observed an unexpected finding of pulmonary dysfunction in children and adolescents who recovered from COVID-19 and long COVID.

Compared to adults, the course of COVID-19 in children and adolescents is mild, with a few weeks of recovery time. The complicated fact is the presence of more objective findings of post-acute sequelae and symptoms in younger patients.

The understanding of multi-organ damage caused by COVID-19 is increasing. Pediatric studies have prioritized issues in mental health during the pandemic. Still, other studies raise concerns about ongoing disease manifestations like increased thrombotic state, microangiopathy, and inflammation.

The primary target of the SARS-CoV-2 virus is the lungs. In adults, CT aided in the diagnosis. But ionization radiations are not practicable in children. Their diagnostic importance is limited as changes in lung parenchyma are less noticeable and pronounced in children due to COVID-19.

The clinical need for pulmonary changes characterization in children and adolescents after COVID-19 is "unmet." Against this background and focus on the pediatric population, a study was conducted by Rafael Heiss, Co-author Lina Tan, and a team to characterize morphologic and functional changes of lung parenchyma using low-field MRI in children and adolescents with previous COVID-19 infection, and a comparison was made with healthy controls. This was the primary outcome measured in the study.

The secondary outcomes were ventilation defect percentage (VDP), perfusion defect percentage (QDP), ventilation/perfusion match, ventilation/perfusion defect, and whole-lung V/Q defect.

The critical points of the study are:

• Low-field MRI, 0.55 Tesla, was used in the study.

• Statistical analysis used the Mann-Whitney test, Kruskal-Wallis test, and corrected Dunn's test.

• P value was less than 0.05 was statistically significant.

• There were 54 children post-COVID-19 with a mean age of 11 years ±3.

• In the control group, nine healthy participants were included with a mean age of 10 years ±3.

• In the COVID-19 group, 29 participants (54 %) recovered from infection.

• 25 participants (46%) had long COVID on the day of enrollment.

• In one recovered participant, Morphologic abnormality was detected.

• (V/Q match) was 81±6.1% in healthy controls for both ventilated and perfused lung parenchyma

• The V/Q match was reduced to 62±19% with a P value of 0.006 in the recovered group and 60±20% with a P value of 0.003in the long COVID group.

• V/Q match in post-COVID patients with:

1. Infection less than 180 days was 63±20% and a P value of P=0.03.

2. Infection,180 to 360 days, was 63±18% with a P value of 0.03.

3. 360 days was 41±12%, and P<0.001

4. These values were less compared to the healthy controls.

• In healthy controls, the overall VDP was lower at 13±3.6% compared to 22±8.1% with P=0.01 in recovered and 25±10% with P=0.002 in the long COVID group.

• QDP was higher in the recovered as 19±19% with P=0.35. In the long COVID group, it was 22±19% and P=0.10 compared to healthy controls, which is 6.5±5.0%.

• In healthy controls, combined V/Q defects were lower with 0.5±0.8% compared to 3.9±4.7% with P=0.04 in the recovered and 5.4±6.6% with P=0.002 in the long COVID group.

• In healthy controls, the V/Q match was higher with 81±6.1% compared to 62±19% with P=0.006 in the recovered and 60±20% with P=0.003 in the long COVID group

• 9% participants reported headache, 28% dyspnea, 2% pneumonia, 7% anosmia, 2% ageusia, 7% fatigue, 11% impaired attention, 2% limb pain and 30% shortness of breath.

The team wrote, "As children develop a robust, cross-reactive, and sustained immune response after SARS-CoV-2infection, the observed pulmonary dysfunction in our study is an unexpected finding."

The researcher concluded, "The low-field MRI is advantageous morphological imaging of lung parenchyma compared to 1.5T and 3T systems."

The team summarised," There is unclarity in the further course and outcome of the observed change. The results warrant further surveillance of persistent pulmonary damage in pediatrics and adolescents after SARS-CoV-2 infection. Given the already existing diagnostic value of lung MRI and the translatability of the technology, these imaging approaches can be rapidly adopted in routine clinical care.

The study's limitations included a lack of comparison with standard references; the functional low-field MRI used free-breathing all intervals; a lack of longitudinal data; and a low number of healthy controls.

Further reading:

Heiss R, Lina Tan, et al. "Pulmonary dysfunction after pediatric COVID-19" Radiology 2022; RSNA