Longitudinal assessment of pulmonary perfusion and ventilation defects in long COVID: A one-year study using … PREFUL MRI, 2025, Ouyang+

[SNT Gatchaman]

Longitudinal assessment of pulmonary perfusion and ventilation defects in long COVID: A one-year study using phase-resolved functional lung PREFUL MRI

Spoiler: Authors

Ouyang; Huang; Wei; Yang; Voskrebenzev; Vogel-Claussen; Guo; Yang

RATIONALE AND OBJECTIVES
The long-term trajectories of pulmonary perfusion and ventilation after recovery from SARS-CoV-2 infection are lacking. This study aims to longitudinally assess changes in perfusion (QDP) and ventilation (VDP) defects using phase-resolved functional lung (PREFUL) MRI in post-SARS-CoV-2 infection.

MATERIALS AND METHODS
This prospective study was conducted from January to May 2023 and included non-hospitalized, COVID-19-positive patients with pneumonia or symptoms suggestive of pneumonia, as well as healthy controls. Serial MRI scans were performed at acute, 3, 6, and 12 months after symptom onset, and healthy controls underwent only one MRI scan. Longitudinal comparisons of QDP and VDPCombined were employed by linear mixed-effects models. Long COVID was defined as persistent SARS-CoV-2 symptoms for at least three months, with associated factors identified through logistic regression.

RESULTS
A total of 60 participants (median age 68.5 years; 30 female) were included. VDPCombined was 21%, 18%, 16%, and 13% at the acute phase, 3 months, 6 months, and 12 months, respectively, with a significant difference observed in the longitudinal comparison (P = 0.034). Moreover, at 12 months, VDPCombined showed no significant difference compared to the healthy control (P = 0.280). QDP also decreased (42%, 36%, 35%, and 19% at acute, 3 months, 6 months, and 12 months, respectively; P < 0.001), but remained significantly higher than in healthy controls at 12 months (P < 0.001). At follow-up, 55% of participants (33 of 60) had long COVID, with higher acute-phase QDP associated with increased odds of developing long COVID (odds ratio, 1.20; P = 0.001).

CONCLUSION
Pulmonary perfusion impairment persists up to 12 months following SARS-CoV-2 infection. Severe perfusion defects during acute phase are a risk factor for the development of long COVID.

HIGHLIGHTS
• Longitudinal PREFUL-MRI tracking reveals distinct recovery patterns of ventilation and perfusion.

• Ventilation defects gradually normalize within 12 months after SARS-CoV-2 infection.

• Perfusion defects persist long term and remain elevated compared with healthy controls.

• Acute-phase perfusion impairment is a strong predictor for developing long COVID.

• A non-invasive MRI framework supports early risk assessment and long-term lung monitoring.


Web | DOI || Computers in Biology and Medicine | Open Access

 

[SNT Gatchaman]

See previous Phase-resolved Functional Lung MRI Reveals Distinct Lung Perfusion Phenotype in Children and Adolescents with Post–COVID-19 Condition (2025)

 

[Hutan]

It's frustrating that Long Covid is so often defined so broadly. So, I'm reading to find out what happened with the non-hospitalised participants.

Phase-resolved functional lung (PREFUL) MRI is a novel technique for assessing lung function, which uses changes in endogenous lung hydrogen proton signals during free breathing as a surrogate for ventilation and perfusion defects [9]. Previous studies demonstrated that the quantification of perfusion defect percentage (QDP) and ventilation defect percentage (VDP) using PREFUL MRI correlates well with dynamic contrast-enhanced (DCE) MRI and hyperpolarized 129Xe MRI [10,11]. PREFUL MRI is performed during free breathing, requires no contrast agents, and is completed within a few minutes (∼1 min/slice), making it an excellent tool for the longitudinal follow-up of COVID-19 patients.

They used a new imaging method that uses no radiation or contrast agents.

Since pulmonary sequelae are the main post-infection symptoms of long COVID, studies have suggested that perfusion defects may be associated with the development of long COVID, yet the relationship between them remains unclear [19]. Prospective longitudinal investigations of changes in pulmonary perfusion may be valuable for understanding the pathophysiological mechanisms underlying long COVID.

Lung issues the 'main post-infection symptoms of long COVID'? I think that's a bit of a stretch. Again - it depends on how you define long COVID...

From January to May 2023, non-hospitalized patients with SARS-CoV-2 infection (confirmed by positive testing in nasopharyngeal or respiratory tract samples) were enrolled if they had COVID-19 pneumonia on CT scan or reported at least one symptom or sign of pneumonia.

It sounds as though even the non-hospitalised patients had or had signs of pneumonia. I think unfortunately that limits the study's ability to tell us about the substantial chunk of long COVID that is post-Covid ME/CFS.

Just checking back with the abstract:

This prospective study was conducted from January to May 2023 and included non-hospitalized, COVID-19-positive patients with pneumonia or symptoms suggestive of pneumonia, as well as healthy controls.

I had assumed that there was a group of non-hospitalised patients and a group of patients with pneumonia/signs of pneumonia and the healthy controls. But, no, I misread that. There are just the two groups, 1. the non-hospitalised patients who had pneumonia/signs of pneumonia and who were sick enough to have a CT scan when they turned up at hospital for assessment, and 2. the healthy controls.