COVID-19 Related Lung Ventilation and Perfusion Injury

At visits 1 and 2, ventilation will be assessed by 99mTc Technegas SPECT ventilation scan and perfusion will be assessed by 99mTc Macroaggregated Albumin SPECT perfusion scan.

At visits 1 and 2, quality of life will be evaluated using the St. George's Respiratory Questionnaire (SGRQ).

At visits 1 and 2, dyspnea will be evaluated using the mMRC (Modified Medical Research Council) Dyspnea Scale.

At visits 1 and 2, exercise capacity will be evaluated using the six-minute walk test (6MWT).

At visits 1 and 2, spirometry will be performed to quantify the forced expiratory volume in one second (FEV1), the forced vital capacity (FVC) and FEV1/FVC.

At visits 1 and 2, plethysmography and the diffusing capacity of the lung for carbon monoxide (DLCO) will be performed.

At visits 1 and 2, airwave oscillometry will be performed to obtain resistance (R) and reactance (X) at 5 Hz (R5) and 19 Hz (R19). The resonance frequency (fres), area above the reactance curve (AX) and the heterogeneity of obstruction (R5-19) will be derived from R and X.