Chest CT scanning for clinical suspected thoracic aortic dissection: beware the alternate diagnosis.

The aim of the study was retrospectively to evaluate the spectrum of chest diseases in patients presenting with clinical suspicion of thoracic aortic dissection in the emergency department. We performed a retrospective medical records review of 86 men and 44 women (ages ranging between 23 and 106 years) with clinically suspected aortic dissection, for CT scan findings and final clinical diagnoses dating between January 1996 and September 2001. All images were obtained by using a standard protocol for aortic dissection. We found aortic dissection in 32 patients (24.6%), 22 of which were Stanford classification type A and 10 Stanford type B. In 70 patients (53.9%), chest pain could not be explained by the CT scan findings. However, in 28 patients (21.5%), CT scanning did reveal an alternate diagnosis that, along with the clinical impression, probably explained the patients' presenting symptoms, including: hiatal hernia (7), pneumonia (5), intrathoracic mass (4), pericardial effusion/hemopericardium (3), esophageal mass/rupture (2), aortic aneurysm without dissection (2), pulmonary embolism (2), pleural effusion (1), aortic rupture (1), and pancreatitis (1). In cases where there is clinical suspicion of aortic dissection, CT scan findings of an alternate diagnosis for the presenting symptoms are only slightly less common than the finding of aortic dissection itself. Although the spectrum of findings will vary depending upon your patient population, beware the alternate diagnosis.