3 research outputs found
Hyperpolarized 129Xe MRI abnormalities in dyspneic participants 3 months after COVID-19 pneumonia: preliminary results
Background: SARS-CoV-2 targets angiotensin-converting enzyme 2 (ACE2) expressing cells in the respiratory tract. There are reports of breathlessness in patients many months post-infection.
Purpose: This study aimedd to determine if hyperpolarized 129Xe MRI (XeMRI) imaging could identify the possible cause of breathlessness in patients three months after hospital discharge following COVID-19 infection.
Materials and Methods: This prospective study was undertaken between August and December 2020, with patients and healthy control volunteers enrolled. All patients underwent: lung function tests; ventilation and dissolved phase XeMRI, with the mean Red Blood Cell (RBC):Tissue Plasma (TP) ratio to be calculated; and a low dose chest CT scored for the degree of post-COVID-19 abnormalities. Healthy controls underwent XeMRI. The intraclass correlation coefficient was calculated for volunteer and patient scans, to assess repeatability. A Wilcoxon rank-sum test and Cohen's effect size calculated to assess for differences between RBC:TP in patient and controls.
Results: 9 patients (mean age 57±7 years, Male = 6) and 5 volunteers (29 ± 3 years, Female = 5) were enrolled. Patient mean time from hospital discharge was 169, range 116-254 days. There was a difference in RBC:TP between patients and controls (0.3 ± 0.1 versus 0.5 ± 0.1, respectively, p = 0.001, effect size = 1.36). There was significant difference between the RBC and gas phase spectral full width at half maximum (FWHM) between volunteers and patients (median ± 95 % confidence interval, 567 ± 1 vs 507 ± 81, p = 0.002 and 104 ± 2 vs 122 ± 17, p = 0.004, respectively). Results were reproducible with Intraclass Correlation Coefficients of 0.82 and 0.88 for patients and volunteers respectively. Participants had normal or near normal CT scans, mean 7/25, range 0-10/25.
Conclusion: Xe MRI showed alveolar-capillary diffusion limitation in all 9 post COVID-19 pneumonia patients despite normal or nearly normal CT scans.
See also the editorial by Dietrich.</p