title: [Community-acquired pneumonia].
abstract: OBJECTIVE
  The diagnosis of community-acquired pneumonia (CAP) is often not possible based only on the clinical symptoms and biochemical parameters.
  
  
  METHODS
  For every patient with the suspicion of CAP, a chest radiograph in two planes should be carried out. Additionally, a risk stratification for the decision between outpatient therapy or hospitalization is recommended.
  
  
  METHODS
  Based on the evaluation of the different radiological patterns as well as their extent and distribution, a rough allocation to so-called pathogen groups as well as a differentiation between viral and bacterial infections are possible; however, because different pathogens cause different patterns an accurate correlation is not feasible by relying purely on imaging.
  
  
  CONCLUSIONS
  The radiological findings serve as proof or exclusion of pneumonia and can also be used to evaluate the extent of the disease (e.g. monolobular, multilobular, unilateral or bilateral). In cases of prolonged disease, suspicion of complications (e.g. pleural effusion or empyema, necrotizing pneumonia or abscess) or comorbid conditions (e.g. underlying pulmonary or mediastinal diseases) computed tomography is an important diagnostic tool in addition to chest radiography. Ultrasound is often used to diagnose pleural processes (e.g. parapneumonic effusion or pleural empyema).
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Allgemeines Krankenhaus, Medizinische Universität Wien, Währinger Guertel 18-20, 1090, Wien, Österreich. sarah.poetter-lang@meduniwien.ac.at.
authors.forename: S
authors.initials: S
authors.lastname: Poetter-Lang
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Allgemeines Krankenhaus, Medizinische Universität Wien, Währinger Guertel 18-20, 1090, Wien, Österreich.
authors.forename: C J
authors.initials: CJ
authors.lastname: Herold
mesh_terms: D000553:Ambulatory Care / Q000379:methods; D017714:Community-Acquired Infections / Q000000981:diagnostic imaging* / Q000382:microbiology* / Q000821:virology*; D003937:Diagnosis, Differential; D019317:Evidence-Based Medicine; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000382:microbiology / Q000821:virology; D011014:Pneumonia / Q000000981:diagnostic imaging* / Q000382:microbiology / Q000821:virology; D013902:Radiography, Thoracic / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography / Q000379:methods*
keywords: Chest radiograph; Computed tomography; Imaging algorithm; Pulmonary consolidation; Radiological patterns