[Nosocomial pneumonia from a radiological perspective].

Due to the high morbidity and mortality, nosocomial pneumonia represents a serious risk in hospitalized patients. The increased risk of infections with multidrug-resistant (MDR) pathogens makes a timely diagnosis and prompt therapy indispensable. A newly occurring or progressive infiltrate in any patient who has been hospitalized for more than 48 h should be viewed with suspicion. In contrast to community acquired pneumonia (CAP), radiography plays a limited role in the diagnosis of hospital-acquired pneumonia (HAP). This is partly due to the technical challenges in imaging of patients who are in a lying position as well as the numerous other possible differential diagnoses. Careful analysis of the various radiological features, such as temporal progression, distribution and appearance can help to narrow down the differential diagnoses. In the absence of a single gold standard, clinical features and appropriate radiological features in addition to cultures obtained from respiratory secretions can help to maximize the diagnostic efficacy and expedite the treatment with appropriate antibiotic therapy.