Imaging plays an important role in the diagnosis of suspected pulmonary infection and may reveal useful signs at chest radiography and ct signs such as the water lily and burrow signs almost always indicate a specific infection whereas findings such as the split pleura sign often suggest a specific diagnosis of empyema in the clinical setting of pneumonia. Imaging plays an integral role in the diagnosis and management of suspected pulmonary infections and may reveal useful signs on chest radiographs and ct scans detected early these signs can often be used to predict the causative agent and pathophysiologic mechanism and possibly to optimize patient . Imaging of pulmonary infection 71 community acquired pneumonia cap community acquired pneumonia refers to an acute infection of the lung in 72 hospital acquired pneumonia hap hospital acquired pneumonia hap may be defined as one occurring after admission 73 ventilator associated . Pulmonary infections have various etiologies and have variegated patterns on radiographs and computed tomography ct imaging plays an important role in the initial diagnosis and follow up of various lung infections radiographs can be normal or non specific during the initial evaluation and ct findings may be more definitive