Review on radiological evolution of COVID-19 pneumonia using computed tomography

Relation of Pulmonary Diffusing Capacity Decline to HRCT and VQ SPECT/CT Findings at Early Follow-Up after COVID-19: A Prospective Cohort Study (The SECURe Study)

A large proportion of patients exhibit persistently reduced pulmonary diffusion capacity after COVID-19. It is unknown whether this is due to a post-COVID restrictive lung disease and/or pulmonary vascular disease. The aim of the current study was to investigate the association between initial COVID-19 severity and haemoglobin-corrected diffusion capacity to carbon monoxide (DLco) reduction at follow-up. Furthermore, to analyse if DLco reduction could be linked to pulmonary fibrosis (PF) and/or thromboembolic disease within the first months after the illness, a total of 67 patients diagnosed with COVID-19 from March to December 2020 were included across three severity groups: 12 not admitted to hospital (Group I), 40 admitted to hospital without intensive care unit (ICU) admission (Group II), and 15 admitted to hospital with ICU admission (Group III). At first follow-up, 5 months post SARS-CoV-2 positive testing/4 months after discharge, lung function testing, including DLco, high-resolution CT chest scan (HRCT) and ventilation-perfusion (VQ) single photon emission computed tomography (SPECT)/CT were conducted. DLco was reduced in 42% of the patients; the prevalence and extent depended on the clinical severity group and was typically observed as part of a restrictive pattern with reduced total lung capacity. Reduced DLco was associated with the extent of ground-glass opacification and signs of PF on HRCT, but not with mismatched perfusion defects on VQ SPECT/CT. The severity-dependent decline in DLco observed early after COVID-19 appears to be caused by restrictive and not pulmonary vascular disease.

Follow-up computed tomography scan in post-COVID-19 pneumonia

The coronavirus disease 2019 (COVID-19) global pandemic can be a severe illness that leads to morbidity and mortality. With the increasing number of COVID-19 pneumonia survivors, several long-term changes may persist, including abnormal imaging of lung parenchyma. In addition to the clinical course, it is vital to follow up on pulmonary imaging during the post-infectious period, which is not routinely required in other common pulmonary diagnoses. Computed tomography (CT) scan of the chest is an effective and diagnostic tool for pneumonia which gives an insight into structural abnormalities within the lungs, complications, and possible progression of the disease. Several studies have monitored COVID-19 pneumonia and its complications using serial CT chest imaging from the initial phase of infection, hospitalization, and post-discharge. Nonetheless, long-term follow-up imaging data in post-COVID-19 is still limited. We have summarized the findings utilizing a systematic review of the literature regarding COVID-19 pneumonia imaging, including long-term follow-up.