Radiographic approach to multifocal consolidation

Consolidation in the lung is seen on radiographs or computed tomography (CT) as increased areas of attenuation that obscure the underlying pulmonary vasculature. There are numerous causes of multifocal consolidative opacities. If the symptoms are acute (days to weeks), the most common causes include edema, pneumonia, and hemorrhage. Depending on the patient's history, signs, and symptoms, the less common causes such as radiation pneumonitis or acute eosinophilic syndrome may be considered. If the symptoms are more chronic (weeks to months), the differential may include alveolar proteinosis, neoplasms such as lymphoma or bronchoalveolar cell carcinoma, granulomatous or inflammatory conditions, and lipoid pneumonia. In this article, we review and discuss characteristic radiographic and clinical findings that can aid the radiologist in prioritizing the differential considerations when faced with multifocal parenchymal consolidative disease.