RecruitingDiagnostic testVentilatory and Perfusion Abnormalities in Individuals With Post-Acute Sequelae of SARS-CoV-2 InfectionProspective cohort study to evaluate the utility of quantitative CT analysis to assess ventilation and perfusion defects in patients with Post-acute Sequelae of SARS-CoV-2 (PASC) and functional limitations