Eva Castañer, MD ; Marta Andreu, MD ; Xavier Gallardo, MD ; Josep Maria Mata, MD, PhD ; María Ángeles Cabezuelo, MD ; Yolanda Pallardó, MD
1 From the Departments of Radiology (E.C., M.A., X.G., J.M.M.) and Pathology (M.A.C.), SDI UDIAT-CD, Institut Universitari Parc Taulí-UAB, Corporació Parc Taulí, Parc Taulí s/n, 08208 Sabadell, Spain; and Department of Radiology, Hospital de la Ribera, Alzira, Spain (Y.P.). Recipient of a Certificate of Merit award for an education exhibit at the 2002 RSNA scientific assembly. Received February 7, 2003; revision requested April 16 and received May 27; accepted June 11.
Thoracic aortic dissection is the most frequent cause of aortic emergency, and unless it is rapidly diagnosed and treated, the result is death. Helical computed tomography (CT) permits the diagnosis of acute aortic dissection with a sensitivity and specificity of nearly 100%. This imaging modality also enables differentiation between proximal aortic dissection (type A in the Stanford classification) and distal aortic dissection (Stanford type B), which are treated differently and have different prognoses. In 70% of patients in whom nontraumatic acute thoracic aortic dissection is diagnosed after evaluation with helical CT, scans show the typical signs of aortic dissection, with rupture and displacement of the intima. CT also can depict other pathologic entities with similar clinical manifestations, such as intramural hematoma and penetrating atherosclerotic ulcer. Awareness of the different radiologic appearances of these disease entities is essential for differential diagnosis. More than one-third of patients with aortic dissection show signs and symptoms indicative of systemic involvement. Because branch-vessel involvement may increase morbidity and mortality, in this group of patients it is important to evaluate the entire aorta so as to determine the distal extent of the dissection and detect any systemic involvement.