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Page 4 of 24 Alberts et al. Vessel Plus 2023;7:34 https://dx.doi.org/10.20517/2574-1209.2023.37

[25]
associated with descending aortic aneurysms, which is formed by different cell types .

ECHOCARDIOGRAPHY OF THE AORTA
When assessing the aorta, it is important to optimize image quality (“knobology”). To improve resolution,
image depth should be reduced, focus should be set to the near field and gain should be adjusted so the
[12]
blood in the lumen is displayed as black on the screen . If possible, increasing the ultrasound frequency
(for example, with dynamic frequency tuning) can increase axial resolution, especially in the near field.
With optimization of these settings, it is possible to differentiate the layers of the aortic wall; the luminal
border of the intima appears as a grey line and the collagen-rich adventitia as a white line [26-28] .

Echocardiography of specific aortic parts
Aortic root
The aortic root is best imaged in the mid-esophageal (ME) aortic valve (AV) short axis (SAX) (30-40°) and
long axis (LAX) view (120-140°) . In the SAX, the three sinuses of Valsalva can be distinguished. The left
[12]
coronary artery is usually well visualized, arising at the left sinus of Valsalva to the right side of the screen.
By carefully turning the probe to the left, the left coronary artery can be tracked down its course. The
bifurcation can be visualized, where the left circumflex artery (LCx) runs up on the screen and the left
anterior descending artery (LAD) runs down to the right side of the screen [29-31] . The right coronary artery,
arising from the right sinus of Valsalva and typically running downwards on the screen, can be more
difficult to image due to its smaller size and potential acoustic shadowing caused by the AV [31,32] .

Measurements to be made at the root include the maximum diameters of the aortic annulus (at the hinge
points of the aortic leaflets), sinus of Valsalva, and the sinotubular junction [Figure 2].

Compared to 2D TEE, the use of 3D TEE can lead to more accurate measurements of the aortic root
structures. Foreshortening can be avoided by adjusting the perpendicular sectional planes . Moreover,
[33]
automated software combined with 3D TEE can result in accurate models and reproducible measurements
of aortic root dimensions .
[34]

Ascending aorta
Compared to the aortic root, the ascending aorta runs steeper. It is best assessed from the ME AV LAX view
by retracting the probe while reducing the probe angle to 90-100° . The SAX view of the ascending aorta
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can be visualized by further reducing the probe angle to 0-10°. The proximal ascending aorta can usually be
well-imaged with TEE. The right mainstem bronchus runs between the esophagus and the distal ascending
aorta, which leads to refraction of the ultrasound. This area is called the blind spot [Figure 1], given that the
distal ascending aorta is visible in only 10% of the cases . For better visualization of this area with TEE, an
[35]
endobronchial fluid-filled balloon catheter device (A-view® Cordatec Inc., Zoersel, Belgium) has been
developed. With this device, the authors were able to visualize the distal ascending aorta in all cases in their
study [35,36] .

Epi-aortic ultrasound serves as an intra-operative alternative for TEE for visualization of the ascending
aorta. With this technique, the surgeon scans the aorta via direct contact between the outer layer of the
[37]
aorta and a high-frequency phased or linear probe .
Aortic arch
The aortic arch is visualized using the upper-esophageal (UE) SAX (70-90°), and the UE LAX view
(0-10°) . The proximal aortic arch and the brachiocephalic artery lay in the blind spot and may be difficult
[12]