- Aspiration is defined as entry of a foreign substance, solid or liquid, into the respiratory tract or inhalation of fumes and vapors.
- Aspiration pneumonia is caused by a direct chemical insult due to the aspirated material or by a primary or secondary bacterial infection.
- Predisposing factors
- Alcoholism, probably the most important predisposing factor
- General anesthesia
- Loss of consciousness
- Structural abnormalities of the pharynx and esophagus
- Neuromuscular disorders
- The clinical and radiologic manifestations are protean, varying from asymptomatic focal inflammatory
reaction with few or no radiologic abnormalities to severe life-threatening disease.
- The major complication associated with aspiration is pulmonary infection.
- Aspiration can lead to the development of lobar or segmental pneumonia, bronchopneumonia, lung abscess, and empyema.
- The posterior segment of the upper lobes and the superior segment of the lower lobes are the most
commonly involved lung sites in aspiration disease, which may mimic other pulmonary diseases such as alveolar proteinosis or neoplasms such as bronchogenic carcinoma and bronchioloalveolar cell carcinoma.
 Imaging Findings
 Plain films
- AP portable chest images may demonstrate bilateral opacities in the middle or lower lung zones.
- On PA and lateral images, the opacities may be localized to the posterior segments of upper lobes or to the superior segments of lower lobes.
- Aspirated low-density organic material such as mineral oil in the tracheobronchial tree or alveolar spaces cannot be diagnosed on plain radiographs, but they can be demonstrated and perhaps measured on CT scans.
- Opaque aspirates are also well demonstrated on CT scans.
 See Also
 External Links
- Jaw Lee. E-medicine rads article.
- Tomás Franquet, Ana Giménez, Nuria Rosón, Sofía Torrubia, José M. Sabaté, and Carmen Pérez. Aspiration Diseases: Findings, Pitfalls, and Differential Diagnosis. RadioGraphics 2000 20: 673-685.