Management of incidental lung nodule is difficult and mainly based on simple morphometric characteristics such as maximum size and shape. Radiomics could play a role in simplifying this management by orientating towards a benign or a malignant origin, by comparing advanced characteristics to a large database of lung nodules.

The primary purpose is to evaluate the performances of a novel tool based on radiomics to characterize incidental lung nodules, discovered on computed tomography.

The secondary objectives are:

• to evaluate the variation in the performances of the software based on various technical aspects of the CT, such as radiation dose, reconstruction algorithm, type of scanner,…
• to compare the performances of this software to those of expert readers,
• to analyze the potential impact of this software on patient's management.

Inclusion Criteria:

• Adult patient (at least 18 years old);
• With a chest CT acquired between Jan 1 2012 and Oct 1 2018 at the Strasbourg University Hospital;
• CT being available over the PACS and exhibiting at least one lung nodule;
• Patient having given its authorization for the exploitation of his medical data for this research.

Exclusion Criteria:

• Patient having expressed direct opposition to participation in this study;
• Patient under juridical protection;
• Patient under tutelage or guardianship.

Patients with a chest CT acquired between Jan 1 2012 and Oct 1 2018 at the Strasbourg University Hospital;