Aortic Dissection on Echo: TTE Findings and the Role of Transesophageal Examination
TTE Findings in Aortic Dissection
The key sign of dissection is the true flap. According to ASE guidelines for artifact identification (Saric M. et al., 2026), a true dissection flap is a wave-like linear mobile echogenic structure. It respects physical anatomical boundaries and acts as a flow divider in the aorta.
Differentiation from Artifacts
Reverberations, side lobe artifacts, and comet tail artifacts can mimic a dissection flap or, conversely, mask the true pathology. Such artifacts are considered potentially serious diagnostic errors (Saric M. et al., 2026). Correct interpretation should rely on the criteria of a true flap: mobility, respect for physical boundaries, and function as a flow divider.
The Role of Contrast
According to ASE guidelines on the use of ultrasonic enhancing agents (Porter T.R. et al., 2018), contrast enhancement of the aorta helps distinguish a true intimal flap from a linear artifact on both TTE and TEE. In patients with dissection, contrast also helps differentiate true and false lumens. The initial contrast bolus should be visualized during the first pass to assess differential flow in the true and false lumens, avoiding attenuation from too large or too rapid intravenous contrast administration.
The Role of Transesophageal Echo (TEE)
CT and TEE are the most common diagnostic modalities for detecting type A aortic dissection (Porter T.R. et al., 2018). TEE allows for differential diagnosis between linear artifacts and intraluminal dissection flap or aortic rupture (as per cited sources Goldstein S.A. et al., 2015). In acute type A dissection, TEE is also used to describe mechanisms of aortic regurgitation with implications for aortic valve repair planning (as per cited data Zoghbi W.A. et al., 2017).
Signs of True and False Lumens
Color Doppler mapping can reveal different flow directions—one through the false lumen, another through the true lumen (according to ASE Guidelines for Vascular Ultrasound-Guided Access, 2023, regarding arterial dissection). Additional CT criteria for differentiating true and false lumens are provided in cited sources (LePage M.A. et al., 2001); detailed threshold criteria for Echo are not provided in fragments [to clarify].
Frequently asked questions
How to distinguish a true dissection flap from an artifact on Echo?
A true flap is a wave-like linear mobile echogenic structure that respects physical boundaries and acts as a flow divider in the aorta. Reverberations, side lobe artifacts, and comet tail artifacts do not possess these properties.
Which modalities are most commonly used for detecting type A dissection?
CT and TEE are the most common diagnostic methods for detecting type A aortic dissection.
How does contrast help in suspected dissection?
Contrast enhancement of the aorta helps distinguish a true intimal flap from a linear artifact on TTE and TEE, as well as differentiate true and false lumens. The bolus is visualized during the first pass, avoiding attenuation from excessive contrast administration.
How does color Doppler help differentiate lumens?
Color Doppler mapping shows different flow directions: one through the false lumen, another through the true lumen.
Why is TEE used in acute type A dissection besides flap visualization?
TEE allows for the description of mechanisms of aortic regurgitation in acute type A dissection, which is important for planning aortic valve repair.