Interpretation of chest radiographs in infants with cough and fever.

An understanding of the appearance of the infant chest radiograph requires an understanding of the anatomy and the physiologic, immunologic, and pathologic processes in the infant's chest. The authors describe the features of the infant chest that most influence the appearance of the chest radiograph in infants with cough and fever. They discuss why confusion sometimes occurs when radiology residents and general radiologists familiar with adult chest radiographs first evaluate the infant chest radiograph. The radiographic appearance of acute inflammation does not look the same in infants as it does in older children and adults. The hallmark of inflammatory lung disease in the infant chest is air trapping on the chest radiograph.