Keywords:
Arteries / Aorta, Vascular, CT-Angiography, Comparative studies, Dissection
Authors:
S. Kandel, N. K. Bhullar, T. Chung, S. Mathur, B. J. Wintersperger, P. Rogalla; Toronto, ON/CA
DOI:
10.26044/ecr2019/C-3138
Aims and objectives
Thoracic aortic dissections,
as part of the acute aortic syndrome,
have hospital mortality rates of 1 in 3 patients for the type of dissection requiring surgical management (Type A) and thus are medical and surgical emergencies.1-2 Accurate and quick diagnosis is necessary,
as a result,
computed tomography (CT) has become the imaging modality of choice.
Contrast-enhanced CT has a sensitivity of 100% and a specificity of 98% and has the advantage of being faster,
and in some cases,
more accessible,
than magnetic resonance imaging or transesophageal echocardiography.3 Aortic dissections are caused by tears in the intima which allows blood to dissect between the layers of the aortic wall.4 An intramural hematoma (IMH) is thought to be caused by a rupture of the vasa vasorum between the aortic wall layers and/or a small tear,
but posing an equally dangerous clinical scenario.
5 Currently,
the imaging protocol to assess an acute aortic syndrome includes an initial non-contrast (NC) examination of the aorta,
followed by a contrast enhanced (CE) examination.
A NC-CT and CE-CT are necessary as an intramural hematoma is classically detected on the NC-CT as a crescentic rim of high density (> 50 Hounsfield units) that can be masked by IV contrast material.
A CE-CT is performed to better assess the anatomy,
dissection flaps or any filling defects in the aorta.6
Often,
it is possible to detect the aortic pathology from an acute aortic syndrome,
particularly an aortic dissection,
on the NC-CT alone,
prior to confirming the dissection on the CE-CT examination.
The aim of the study to evaluate wether thoraci aortic dissection can be reliable detected on non-contrast CT of the chest.