Functional alterations due to post-COVID-19 lung lesions — lessons from a multicenter V/Q SPECT/CT based registry

The COVID-19 pandemic has left many survivors with persistent respiratory symptoms such as dyspnea, chronic cough, and reduced exercise capacity. Fibrosis-like abnormalities on high-resolution CT are frequently reported in theses patient. This study aimed to describe the morphological pulmonary abnormalities identified on V/Q SPECT/CT after COVID-19 infection and to evaluate their functional consequences on regional ventilation and perfusion. We also sought to identify clinical predictors of abnormal V/Q SPECT/CT findings. This retrospective multicenter study was based on a national registry of patients referred for V/Q SPECT/CT because of persistent respiratory symptoms after COVID-19 infection. CT abnormalities were characterized using standard radiological criteria. Ventilation and perfusion were visually graded using a five-point scale. Clinical, demographic, and acute COVID-19 characteristics were analyzed to identify predictors of abnormal imaging. Among the 217 included patients (mean age 58 ± 15 years), 122 (56%) presented pulmonary abnormalities on V/Q SPECT or CT. The most frequent parenchymal abnormalities were reticulations, consolidations, atelectasis, emphysema, and ground-glass opacities. Emphysema, consolidations, and fibrosis were associated with the most severe impairments of both ventilation and perfusion. Age and pre-existing chronic lung disease were the strongest predictors of abnormal imaging, while a mild acute COVID-19 course without oxygen therapy was protective. V/Q SPECT/CT provides a comprehensive structural and functional assessment of long COVID pulmonary sequelae. It allows the differentiation between reversible inflammatory lesions and persistent structural abnormalities with lasting functional consequences.