Clearing patterns of pulmonary infarction and slowly resolving pneumonia

Previous authors have suggested that the radiographic clearing pattern of pulmonary infarction is specific and permits differentiation from pneumonitis. Pulmonary infarcts are said to "shrink" or "melt" and pneumonitis consolidations to clear diffusely. Chest radiographs of 4 patients with angiographically confirmed pulmonary infarction and 5 with slowly resolving pneumonitis were examined, in random case order, by three independent radiologists unaware of the diagnosis. All observers found the shrinking pattern in 3 of the 4 cases of pulmonary infarction and in 1 case of pneumonitis. The shrinking pattern is not specific for pulmonary infarction; it may be related to fibrotic organization of pulmonary consolidation.