Detailed MRI reveals pulmonary vascular abnormalities in COVID long-haulers
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.”
In an editorial published in Radiology alongside the research, Jim Wild, PhD, Professor of Magnetic Physics at the University of Sheffield, and Guilhem Collier, PhD, a research scientist in Pulmonary Imaging, also at the University of Sheffield, praised the experts’ combining of CT vascular and xenon gas exchange modalities, but suggested that there is still work to be done in that respect:
“In further work it would also be of significant interest to follow up on this detailed patient cohort study and see if the perceived gas transfer abnormality from xenon MRI improves alongside the lung function, vascular CT or complementary DCE lung perfusion MRI methods that can help quantify microvascular capillary perfusion abnormality.”
Both the editorial and the detailed abstract can be viewed in Radiology.
More on long COVID:
PET scans spot brain abnormalities in long COVID patients
NIH grants $3.5 million toward researching COVID's neurological impact
Specialized CT protocol reveals small airways disease in COVID long haulers
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.