Diffuse Infiltrative Lung Disease

Diffuse infiltrative lung disease refers to disorders with imaging abnormalities consisting of diffuse opacities that may manifest as reticular opacities, micronodules, hazy opacities or frank airspace disease. Diffuse infiltrative lung disease often refers to diffuse radiographic abnormalities that are optimally characterized on thin-section CT (e.g. interstitial lung disease such as UIP or NSIP). However, diffuse opacities on radiography may manifest with other findings on CT (e.g. cysts or emphysema). In addition, patients with diffuse infiltrative lung disease on CT may have normal radiographs (e.g. NSIP or pneumocystis pneumonia). The next chapters address pulmonary diseases manifesting with diffuse opacities on either chest radiography or CT, with an emphasis on the formulation of a narrow differential diagnosis.