¹²⁹Xe MRI ventilation defects in ever-hospitalised and never-hospitalised people with post-acute COVID-19 syndrome

Abstract

BackgroundPatients often report persistent symptoms beyond the acute infectious phase of COVID-19. Hyperpolarised 129Xe MRI provides a way to directly measure airway functional abnormalities; the clinical relevance of 129Xe MRI ventilation defects in ever-hospitalised and never-hospitalised patients who had COVID-19 has not been ascertained. It remains unclear if persistent symptoms beyond the infectious phase are related to small airways disease and ventilation heterogeneity. Hence, we measured 129Xe MRI ventilation defects, pulmonary function and symptoms in ever-hospitalised and never-hospitalised patients who had COVID-19 with persistent symptoms consistent with post-acute COVID-19 syndrome (PACS).MethodsConsenting participants with a confirmed diagnosis of PACS completed 129Xe MRI, CT, spirometry, multi-breath inert-gas washout, 6-minute walk test, St. George’s Respiratory Questionnaire (SGRQ), modified Medical Research Council (mMRC) dyspnoea scale, modified Borg scale and International Physical Activity Questionnaire. Consenting ever-COVID volunteers completed 129Xe MRI and pulmonary function tests only.ResultsSeventy-six post-COVID and nine never-COVID participants were evaluated. Ventilation defect per cent (VDP) was abnormal and significantly greater in ever-COVID as compared with never-COVID participants (p<0.001) and significantly greater in ever-hospitalised compared with never-hospitalised participants who had COVID-19 (p=0.048), in whom diffusing capacity of the lung for carbon-monoxide (p=0.009) and 6-minute walk distance (6MWD) (p=0.005) were also significantly different. 129Xe MRI VDP was also related to the 6MWD (p=0.02) and post-exertional SpO2 (p=0.002). Participants with abnormal VDP (≥4.3%) had significantly worse 6MWD (p=0.003) and post-exertional SpO2 (p=0.03).Conclusion129Xe MRI VDP was significantly worse in ever-hospitalised as compared with never-hospitalised participants and was related to 6MWD and exertional SpO2 but not SGRQ or mMRC scores.Trial registration numberNCT05014516.

Postacute COVID-19 Syndrome: 129Xe MRI Ventilation Defects and Respiratory Outcomes 1 Year Later

“…Thoracic CT was acquired during the 3-month visit. 129 Xe MRI VDP and CT results acquired 3-months post-COVID-19 infection were previously reported ( 15 ); here, we report measurements at 15-months post-COVID-19 infection and compare them with 3-month measurements.…”

“…In this prospective study, participants were recruited in a convenience series between July 2020 and August 2021 from two quaternary care centers and research sites (Site 1: Robarts Research Institute, London Canada; Site 2: St Joseph's Healthcare Hamilton, Hamilton Canada) and all provided written-informed consent to ethics board (HSREB #113224 London; HiREB #12672, Hamilton), Health Canada-approved protocols ( www.clinicaltrials.gov NCT05014516). Inclusion criteria and participant recruitment were previously described ( 15 ). Briefly, inclusion criteria consisted of individuals aged 18 to 80 years with a public-health confirmed case of COVID-19 and persistent symptoms, including but not limited to respiratory, neurological and metabolic systems.…”

“…Chest CT is nearly universally available and the clinical-mainstay for the evaluation of pulmonary abnormalities resultant from COVID-19 infection ( 9 ) and in people with PACS ( 10 ). In PACS, 129 Xe MRI previously revealed abnormal gas-exchange measurements ( 11 - 14 ) and ventilation defects ( 11 , 15 ). In patients with normal pulmonary function and normal or mildly abnormal chest CT ( 12 - 15 ), some of these MRI findings were accompanied by highly abnormal quality-of-life scores and exercise capacity.…”

“…In PACS, 129 Xe MRI previously revealed abnormal gas-exchange measurements ( 11 - 14 ) and ventilation defects ( 11 , 15 ). In patients with normal pulmonary function and normal or mildly abnormal chest CT ( 12 - 15 ), some of these MRI findings were accompanied by highly abnormal quality-of-life scores and exercise capacity. The longitudinal trajectory of such abnormal MRI measurements and their relationship to persistent symptoms remains unclear.…”

“…Hyperpolarized 129 Xe MRI ( 16 ) provides a way to quantify airway dysfunction, including the functional consequences of airway inflammation or remodelling in asthma ( 17 ). In people with PACS, MRI ventilation defects were shown to be related to exercise limitation and post-exertional dyspnea ( 15 ). Ventilation defects are temporally and spatially reproducible in people with airways disease ( 18 ), with high reproducibility across different sites ( 19 ).…”