1. Correct Answer: B. The aneurysm has been repaired

Rationale: This is an image of a native aorta. An open or endovascular repair would appear as an echogenic foreign body within an aneurysm sac.

This case illustrates the importance of imaging the entirety of the abdominal aorta from the proximal aspect to the bifurcation, in both the transverse and longitudinal planes.

Saccular aneurysms (Choice A) expand asymmetrically from the aortic wall and are best seen in the transverse plane as it gives a circumferential view of the aorta. Even with fusiform aneurysms, which expand symmetrically, longitudinal views are prone to error due to the cylinder tangent effect (Figure 67.16). In this axis, the widest diameter is the true diameter. It is possible to underestimate the diameter of the aorta if the imaging plane is not midline, but parasagittal (Choice C). In the transverse axis, the smallest diameter is the true diameter, and it is possible to overestimate the true diameter if the angle of insonation is not exactly perpendicular. This is especially true when measuring a tortuous aorta.

Choice D is possible because in this view, the distal aorta is not completely visualized. A complete abdominal aorta exam begins proximally at the xiphoid process and extends distally to the bifurcation of the aorta into the iliac arteries. While this image includes the more proximal part of the infrarenal aorta, it does not include the entire segment down to the bifurcation. Complete imaging of the abdominal aorta is important since 95% of abdominal aortic aneurysms are infrarenal.

1. Dean AJ. Abdominal aorta. In: Cosby KS, Kendall JL, eds. Practical Guide to Emergency Ultrasound. 2nd ed. Wolters Kluwer Health; 2014:156-171.

2. Guideline developed in collaboration with the American College of Radiology; Society of Radiologists in Ultrasound. AIUM practice guideline for the performance of diagnostic and screening ultrasound examinations of the abdominal aorta in adults. J Ultrasound Med. 2015;34(8):1-6. doi:10.7863/ultra.34.8.15.13.0003.

3. Noble VE, Nelson BP, eds. Abdominal aorta ultrasound. In: Manual of Emergency and Critical Care Ultrasound. 2nd ed. Cambridge University Press; 2011:115-131.

4. Tainter CR. Abdominal aorta. In: Soni NJ, Arntfield R, Kory P, eds. Point-of-Care Ultrasound. 1st ed. Elsevier; 2015:167-173.

2. Correct Answer: A. Outpatient vascular surgery follow-up

Rationale: Figure 67.2 shows an AAA with a stent-graft in place following an endovascular aortic aneurysm repair (EVAR). The hyperechoic ring represents the walls of the stent-graft, which lies within the lumen of the aneurysmal aorta. The aneurysm sac is notable for the presence of extensive mural thrombus. The walls of the stent-graft could be mistaken for a calcified, non-aneurysmal aortic wall if care is not taken to identify the true aortic wall.

Urgent inpatient vascular surgery consultation (Choice B) or CTA of the abdomen and pelvis (Choice D) is unnecessary because the patient has no signs or symptoms of post-EVAR complications. She requires only routine outpatient vascular surgery follow-up and surveillance with CTA or ultrasound. Although there is evidence of mural thrombus in the aneurysm sac, there is no role for anticoagulation (Choice C) in this setting. See also Figure 67.17.

1. Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018;67(1):2-77.e2. doi:10.1016/j.jvs.2017.10.044.

2. Dean AJ. Abdominal aorta. In: Cosby KS, Kendall JL, eds. Practical Guide to Emergency Ultrasound. 2nd ed. Wolters Kluwer Health; 2014:156-171.

3. Correct Answer: A. Outpatient follow-up with vascular surgery

Rationale: Figure 67.3 shows a massively distended bladder that is above the level of the umbilicus. The fluid-filled bladder allows for excellent imaging of the aneurysmal aorta posterior. The aorta is remarkable for the presence of an endovascular stent-graft.

The patient’s symptoms can be attributed to urinary retention and a possible urinary tract infection. A Foley catheter was placed and >1 L of urine was drained, with immediate resolution of his abdominal distension and pain. As the patient is asymptomatic from his previously repaired AAA, visible deep to the distended bladder (see image below), only routine follow-up with his vascular surgeon and surveillance imaging is required (Choice A). Emergent vascular surgery consult (Choice B) or CTA of the abdomen and pelvis (Choice D) is not warranted. Beta-blockers (Choice C) have not been shown to limit aneurysm sac expansion or increase regression post-EVAR.

This image demonstrates the importance of identifying the vertebral shadow as a key landmark for locating the aorta, which lies directly above it. This is particularly important when normal anatomy may be altered by previous surgery or acute issues, such as massive bladder distension (in this case). One could easily mistake the distended bladder for a massive 9 cm AAA and assume the aorta behind it to be the vertebral body. Through the bladder, posterior acoustic enhancement makes the anterior wall of the aorta much brighter than usual, similar to the appearance of the anterior surface of the vertebra. Additionally, the presence of the endovascular stent-graft and mural thrombus in the residual aneurysm sac significantly alter the usual anechoic appearance of the aorta. See also Figure 67.18.

1. Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018;67(1):2-77.e2. doi:10.1016/j.jvs.2017.10.044.

2. Kim W, Gandhi RT, Peña CS, et al. Effect of β-blocker on aneurysm sac behavior after endovascular abdominal aortic repair. J Vasc Surg. 2017;65(2):337-345. doi:10.1016/j.jvs.2016.06.111.

4. Correct Answer: B. Celiac trunk

Rationale: The celiac trunk is the first major branch of the abdominal aorta. It arises from the anterior aspect of the aorta, at the T12 vertebral level, and branches into the splenic artery to the left (right of the image) and the common hepatic artery to the right (left of the image), forming the characteristic “seagull sign,” seen in Figure 67.4. See also Figure 67.19. The third branch of the trunk, the left gastric artery, often cannot be visualized on ultrasound.

The descending aorta (Choice A) is the round hypoechoic structure lying directly above the vertebral body. In this image, the left lateral wall of the aorta is obscured by an edge artifact. The SMA (Choice C) is the second major branch of the abdominal aorta. It arises from the anterior aspect of the aorta approximately 1 cm distal to the origin of the celiac trunk, at the L1 vertebral level, and does not have the characteristic bifurcation seen here. The bilateral renal arteries (Choice D) arise from the lateral aspects of the aorta, just distal to the origin of the SMA. They are often poorly visualized on ultrasound.

1. Dean AJ. Abdominal aorta. In: Cosby KS, Kendall JL, eds. Practical Guide to Emergency Ultrasound. 2nd ed. Wolters Kluwer Health; 2014:156-171.

2. Noble VE, Nelson BP, eds. Abdominal aorta ultrasound. In: Manual of Emergency and Critical Care Ultrasound. 2nd ed. Cambridge University Press; 2011:115-131.

3. Tainter CR. Abdominal aorta. In: Soni NJ, Arntfield R, Kory P, eds. Point-of-Care Ultrasound. 1st ed. Elsevier; 2015:167-173.

5. Correct Answer: C. Superior mesenteric artery

Rationale: The SMA is the second major branch of the abdominal aorta. It arises from the anterior aspect of the aorta approximately 1 cm distal to the origin of the celiac trunk, at the L1 vertebral level. The SMA has a surrounding hyperechoic fat layer that forms the characteristic “mantle clock sign.” Other important landmarks in this view include the splenic vein and the left renal vein (see Figure 67.20). The splenic vein can be seen coursing anteriorly to the SMA on its way to join the superior mesenteric vein (SMV) at the portal confluence. The left renal vein courses between the SMA and the aorta to empty into the inferior vena cava (IVC).

The aorta (Choice A) is the round hypoechoic structure lying directly above the vertebral body.

The celiac trunk (Choice B) is the first major branch of the abdominal aorta and will have branched off approximately 1 cm proximal to the origin of the SMA. The inferior mesenteric artery (Choice D) arises from the anterior aspect of the aorta at the L3 vertebral level. It is not well-visualized on the standard POCUS examination.

1. Dean AJ. Abdominal aorta. In: Cosby KS, Kendall JL, eds. Practical Guide to Emergency Ultrasound. 2nd ed. Wolters Kluwer Health; 2014:156-171.

2. Noble VE, Nelson BP, eds. Abdominal aorta ultrasound. In: Manual of Emergency and Critical Care Ultrasound. 2nd ed. Cambridge University Press; 2011:115-131.

3. Tainter CR. Abdominal aorta. In: Soni NJ, Arntfield R, Kory P, eds. Point-of-Care Ultrasound. 1st ed. Elsevier; 2015:167-173.

6. Correct Answer: D. Deep inspiration with breath-hold

Rationale: Figure 67.6 shows overlying bowel gas.

A deep breath will displace the abdominal organs downward, improving imaging of the gallbladder or the heart in a subcostal approach. However, it is unlikely to displace bowel gas sufficiently to allow imaging of the abdominal aorta.

Gentle continuous pressure, often with a slight jiggling of the probe, encourages peristalsis and movement of bowel gas. A demonstration of this technique can be seen in Video 67.14.

The right coronal approach (from the mid-axillary line just below the diaphragm) uses the liver as an acoustic window to avoid bowel gas. The left coronal approach can also be used, though the spleen offers a smaller acoustic window. There are several key limitations to consider. The distal aorta will often be incompletely evaluated due to the cephalad positioning of the probe. Also, image resolution may be poor as the aorta will be further from the probe compared to the standard midline views. Left lateral decubitus positioning is often used in conjunction with the right coronal approach to further improve imaging. In this position, gravity encourages the bowel to fall away from the abdominal aorta. Similarly, right lateral decubitus positioning can be used with the left coronal approach.

1. Dean AJ. Abdominal aorta. In: Cosby KS, Kendall JL, eds. Practical Guide to Emergency Ultrasound. 2nd ed. Wolters Kluwer Health; 2014:156-171.

2. Noble VE, Nelson BP, eds. Abdominal aorta ultrasound. In: Manual of Emergency and Critical Care Ultrasound. 2nd ed. Cambridge University Press; 2011:115-131.

3. Tainter CR. Abdominal aorta. In: Soni NJ, Arntfield R, Kory P, eds. Point-of-Care Ultrasound. 1st ed. Elsevier; 2015:167-173.

7. Correct Answer: D. From the midline, with the probe above the xiphoid process and angled caudad

Rationale: Alternative views are often necessary for a complete evaluation of the aorta. Each approach has its advantages and limitations.

The advantage of scanning lateral to the midline (Choice A) is that the probe can be moved from proximal to distal to evaluate the entire length of the abdominal aorta. Additionally, when in long axis, this oblique scan plane allows you to visualize the aortic bifurcation into the bilateral iliac arteries, although this approach may be limited by the presence of bowel gas.

Imaging from the right or left coronal plane (Choice B) uses the liver or spleen as an acoustic window, but views of the distal aorta are limited and the resolution may be poor due to the increased distance of the aorta from the probe.

The approach from below the umbilicus (Choice C) is often used to image the distal aorta when obscured by overlying bowel gas. The disadvantage of this technique is that it often offers no view of the more proximal aspects of the abdominal aorta and can be obscured by bowel gas as well.

With the probe above the xiphoid process (Choice D), the presence of bone and air would preclude imaging of the abdominal vessels, making this choice the least effective strategy.

1. Dean AJ. Abdominal aorta. In: Cosby KS, Kendall JL, eds. Practical Guide to Emergency Ultrasound. 2nd ed. Wolters Kluwer Health; 2014:156-171.

2. Noble VE, Nelson BP, eds. Abdominal aorta ultrasound. In: Manual of Emergency and Critical Care Ultrasound. 2nd ed. Cambridge University Press; 2011:115-131.

3. Tainter CR. Abdominal aorta. In: Soni NJ, Arntfield R, Kory P, eds. Point-of-Care Ultrasound. 1st ed. Elsevier; 2015:167-173.

8. Correct Answer: B. Scanning in the short axis in the standard transverse plane

Rationale: The hyperechoic line indicated by the arrow is a reverberation artifact from the overlying SMA. It is formed by the reflection of ultrasound waves between the anterior and posterior walls of the SMA due to the hyperechoic fat layer surrounding the vessel. This hyperechoic fat gives the SMA its characteristic “mantle clock” appearance in transverse imaging. The reverberation artifact often appears as a hyperechoic mass (known as a “pseudo-mass”) or, in this case, a bright stripe mimicking a dissection flap.

This artifact can be eliminated by imaging in such a way that the ultrasound beam does not pass directly through the SMA, such as through a coronal (Choice A) or oblique (Choice C) plane. Scanning in the standard transverse plane may not eliminate this artifact, as the ultrasound beam still passes through the anechoic SMA with hyperechoic edges, which creates the reverberation artifact. If the object remains despite changes in the scanning approach, the ultrasound finding should be confirmed with alternative imaging such as CT or MRI (Choice D).

1. Kokhanovsky N, Nachtigal A, Reindorp N, Zeina AR. Superior mesenteric artery-related aortic pseudomass as a form of reverberation artifact in a 10-year-old boy. J Clin Imaging Sci. 2014;4:73. doi:10.4103/2156-7514.148268.

2. Mann GS, Robinson AJ, LeBlanc JG, Heran MK. Abdominal aortic pseudomass in a child: a diagnostic red herring. J Ultrasound Med. 2008;27(2):307-310. doi:10.7863/jum.2008.27.2.307.

3. Rubin JM, Gao J, Hetel K, Min R. Duplication images in vascular sonography. J Ultrasound Med. 2010;29(10):1385-1390. doi:10.7863/jum.2010.29.10.1385.

9. Correct Answer: A. Consult vascular surgery emergently

Rationale: This is a case of a ruptured aortic aneurysm. The longitudinal (sagittal) image in Figure 67.8A shows a markedly dilated aortic aneurysm with a maximum anteroposterior diameter of 8 cm and a posterior para-aortic hypoechoic area that is concerning for a hematoma. In the transverse (axial) image (Figure 67.8B), color Doppler confirms the flow of blood out of the aorta into the hypoechoic area.

Evidence of rupture is often not apparent on ultrasound, and the clinical triad of back and/or abdominal pain, hypotension, and AAA is sufficient to warrant emergent vascular surgery consultation (Choice A) with a goal door-to-intervention time of 90 minutes. Further confirmation with CT abdomen/pelvis (Choice B) is not necessary prior to consultation and should not delay evaluation of this hemodynamically unstable patient.

Further fluid boluses should be deferred to allow for permissive hypotension (or hypotensive hemostasis) with a target systolic BP of 70 to 90 mm Hg, as long as perfusion is adequate, pending definitive treatment.