Inclusion criteria:  Major subject (≥18 years old) Emergency consultant subject with a final diagnosis of pneumonia, diagnostic code J18 and J15 with imaging: standard radiography or low dose scanner from 03/01/2019 to 02/29/2020 Subject not having expressed their opposition, after information, to the reuse of their data for the purposes of this research  Exclusion criteria:  Subject having expressed opposition to participating in the study Absence of emergency imaging Subject under guardianship or guardianship Subject under safeguard of justice