The PA view is slightly overpenetrated. Lumbar interspaces are visible in this patient. The cardiac silhouette is large. The left costophrenic angle is blunted and there appears to be increased density behind the hea that paially obscures the diaphragm. There are bilateral linear opacities in the lower zones consistent with discoid or linear atelectasis. Mycoplasma or atypical pneumonia may present with a similar radiographic picture, but in the absence of an acute febrile illness, that diagnosis seems unlikely. Chronic bronchitis is a clinical diagnosis and is defined per ATS criteria as a history of chronic sputum production for most of the days in a 3-mo period for at least two successive years. The chest x-ray may show large pulmonary vessels if there is longstanding cor pulmonale and generally does not show any focal opacities. Although the patient is obese and 60% of patients with obstructive sleep apnea (OSA) are overweight, there is no history of hypersomnolence, sleep fragmentation, sleep disorder, or other clinical evidence of sleep apnea syndrome. The clinical scenario presented is suggestive of pulmonary embolism. The physical exam suggesting bilateral atelectasis and the chest radiograph depicting those changes and representing congestive atelectasis are consistent with that diagnosis.