[Acute, atraumatic changes of the lower respiratory tract in the child in thoracic roentgen imaging. Recognition and appreciation of radiological changes].

The diagnosis of acute, non-traumatic diseases of the lower respiratory tract requires exact knowledge of the specific anatomy, physiology and pathology of the pediatric chest. The absolutely and relatively smaller airways, as compared with those of adults, and the undeveloped collateral ventilation result in radiological appearances that are unique in children. Viral pneumonia is predominant only in small children up to an age of 2 years. With increasing age, there is a higher incidence of bacterial pneumonia. The differentiation of viral and bacterial etiology of a pneumonia is not possible on the basis of chest radiographs. In acute pediatric imaging, possible aspiration of foreign bodies has to be considered. Since most foreign bodies cannot be detected radiographically, indirect features such as hyperinflation or mediastinal shifts have to be evaluated. Primary lung tumors are rare in children. More common are metastases with known primary tumors. Neuroblastoma or lymphomas may mimic intrapulmonary pathologies.