Pitfalls in the Diagnosis of Thoracic Aortic Dissection at CT Angiography

Cardiac

 

http://radiographics.rsna.org/content/20/2/309.full

Poonam Batra, MD ; Brian Bigoni, MD ; John Manning, MD ; Denise R. Aberle, MD ; Kathleen Brown, MD ; Eric Hart, MD2 ; Jonathan Goldin, MD, PhD

1 From the Department of Radiological Sciences, UCLA Medical Center, 10833 Le Conte Ave, Los Angeles, CA 90095-1721. Recipient of a Certificate of Merit award for a scientific exhibit at the 1998 RSNA scientific assembly. Received February 26, 1999; revision requested May 17 and received July 1; accepted July 8.

Two hundred seventy-five computed tomographic (CT) angiograms of the thoracic aorta were obtained over a period of approximately 4 years in patients with suspected or known aortic dissection. In all cases, unenhanced images were initially obtained, followed by contrast material–enhanced images. A variety of pitfalls were encountered that mimicked aortic dissection. These pitfalls were attributable to technical factors (eg, improper timing of contrast material administration relative to image acquisition); streak artifacts generated by high-attenuation material, high-contrast interfaces, or cardiac motion; periaortic structures (eg, aortic arch branches, mediastinal veins, pericardial recess, thymus, atelectasis, pleural thickening or effusion adjacent to the aorta); aortic wall motion and normal aortic sinuses; aortic variations such as congenital ductus diverticulum and acquired aortic aneurysm with thrombus; and penetrating atherosclerotic ulcer. Although several of these pitfalls are easy to recognize and therefore unlikely to present a diagnostic problem, others are potentially confusing. Familiarity with these common pitfalls, coupled with knowledge of normal intrathoracic anatomy, will facilitate recognition of true aortic dissection and help avoid misdiagnosis at thoracic aortic CT angiography.