Computed tomography findings of aspiration pneumonia in 53 patients.

Aim: No large case series has so far shown the chest computed tomography (CT) features in patients with aspiration pneumonia, despite the fact that aspiration pneumonia is the most common pulmonary disease in the elderly and is regarded as gravity-dependent pneumonia. The aim of the present study was to elucidate the CT features based on the patients' status in patients with dysphagia-associated aspiration pneumonia.

Methods: A total of 53 patients, who were hospitalized because of pneumonia and subsequently confirmed to have dysphagia by videofluorography, were entered into this study. The CT findings were independently evaluated by two radiologists who were unaware of the patients' clinical information. The relationships between the patients' status and the CT patterns of pneumonia or their distributions were analyzed.

Results: There were eight patients (15%) with lobar pneumonia, 36 patients (68%) with bronchopneumonia and nine patients (17%) with bronchiolitis. Posterior lung predominance was seen in 49 patients (92%). In the craniocaudal observation, lower lung predominance was found in 25 patients (47%) and diffuse distribution was seen in 28 patients (53%). A decreased performance status was significantly associated with a diffuse distribution (P=0.039).

Conclusions: Aspiration pneumonia more frequently presented as a bronchopneumonia pattern followed by a bronchiolitis pattern on CT. Their distributions were characterized by gravity dependence, and anterior- or upper lung-limited pneumonia might not be due to dysphagia-associated pneumonia.