Predicting the Progression to Chronic Fibrosis of Lung Lesions Related to Covid-19 Infection From Chest CT Images

The main differences observed between SARSCoV-2 pneumonia and other epidemic viral pneumopathies (e.g., seasonal influenza) are the greater infectivity of SARSCoV-2, the clinical severity of the disease, particularly in young patients without co-morbidities, and the observation of radiological images related to significant parenchymal aggression in a large number of patients.

The lesions in the acute phase correspond essentially to bilateral ground glass opacity more or less associated with condensations which would be markers of more severe infections.

The major scope of the lesions in the acute phase raises the question of whether or not the scanning anomalies are completely resolved over time, and the possible impact on lung function. This risk of sequelae is very important to study given the large number of patients affected by SARSCoV-2, especially since these are often young patients who appear to be "healthy".

In the current context of the CoV-2 SARS pandemic, the improved quality and availability of diagnostic scanners provides a wealth of information on the semiology and progression of lung disease with minimal exposure to ionizing radiation. A majority of hospitalized patients with SARSCoV-2 received a CT scan in the early phase of the disease. Indeed, the French Society of Radiology has recommended the performance of a CT scan without injection in thin sections in case of suspicion or for confirmation of the diagnosis in patients presenting initial or secondary clinical signs of severity and justifying hospital management due to the initial lack of reagents for performing biological tests (RT-PCR) and the high sensitivity of the CT scan and its specificity in epidemic periods.

The present study aims to study the kinetics of lung involvement in SARS CoV 2, to study the predictive character of the chest CT scan performed at the patient's discharge on the existence of radiological sequelae at 3 months but also at 1 year in order not to misunderstand the constitution of late fibrosis after partial resolution of the CT images. The investigatos will study the correlation between possible radiological abnormalities and the clinical presentation (patient symptoms and lung function). The rigorous follow-up of these patients will allow us to set up, if necessary, early treatment of the detected abnormalities (inhaled corticoids in case of bronchial or bronchiolar damage, study of the place of an anti-fibrosis treatment in case of fibrosis,...).