Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we will assume that you are happy to receive all cookies and you will not see this message again. Click 'Find out more' for information on how to change your cookie settings.

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 aimed 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.

Original publication

DOI

10.1148/radiol.2021210033

Type

Journal article

Journal

Radiology

Publication Date

25/05/2021