New MRI measurements of patients with post-acute-COVID-19-syndrome have revealed pulmonary vascular abnormalities known to limit physical exertion. 

Post-acute-COVID-19-syndrome, or PACS, is characterized by the presence of COVID symptoms that can persist for up to 12 weeks or more beyond the initial onset of symptoms. These symptoms can cause extreme fatigue, cognitive dysfunction, muscle weakness, difficulty breathing on exertion and while at rest—among others—and can significantly affect an individual’s quality of life, experts involved in new research published this week in Radiology explained. 

To better understand the precise origin of these symptoms in COVID long-haulers, researchers had 40 study participants (6 controls) inhale polarized xenon gas in order to conduct 129Xe MRI exams, which assess vascular microstructure, ventilation and gas exchange in the lungs. Additionally, the participants underwent chest CT scans and an array of other pulmonary assessments. Out of the 34 PACS participants, 22 had never been hospitalized for COVID. 

Compared to the controls, PACS patients exhibited lower 129Xe MRI measures associated with CT pulmonary vascular density, diffusing capacity of the lung for carbon monoxide, exercise capacity and dyspnea. This was consistent throughout both ever-hospitalized and never-hospitalized participants.

“In our study, both CT and 129Xe MRI suggest temporally persistent pulmonary vascular density and gas-transfer abnormalities that were related to exercise limitation and exertional dyspnea,” corresponding author Grace Parraga, of the Department of Physiology and Pharmacology at Western University, and colleagues wrote. “We observed abnormal 129Xe MRI gas-exchange measurements in never-hospitalized participants with COVID and some 129Xe MRI measurements were worse in never-hospitalized patients compared to controls.”