How Aortic Aneurysms Are Diagnosed

aortic aneurysm diagnosis
Illustration by Joshua Seong. © Verywell, 2018.

If a person has an aortic aneurysm, it is important to make the diagnosis as early as possible, in order to prevent rupture or other complications. Doctors diagnose aortic aneurysms with imaging studies that can show the presence or absence of an aneurysm, its size, its location, and its effect on surrounding structures. Imaging studies can also give important clues regarding the likelihood of early rupture.

In some people, the chances of having a rupture are high at the time the diagnosis is made, and early surgery is needed. In others, rupture does not appear imminent. In these people the diagnosis creates an opportunity for regular monitoring to determine how rapidly the aneurysm is growing. This allows the doctor to decide if and when elective surgical repair may become necessary.

This proactive monitoring can only be done if you know the aortic aneurysm is there. All too often, unfortunately, people aren't diagnosed until a catastrophic rupture actually occurs—and all too often that’s too late. People who are at increased risk of developing an aortic aneurysm should be screened for this condition, so a diagnosis can be made early enough to do something about it.

Abdominal Aortic Aneurysms

Ultrasounds

In people who have no symptoms but are being screened for an abdominal aortic aneurysm, the diagnostic test used most commonly is an ultrasound examination.

The ultrasound test uses sound waves to construct an image of various parts of the body.

Ultrasound studies are extremely effective in diagnosing abdominal aortic aneurysms, as long as they are at least 3 cm in diameter. Because the test is relatively quick and is non-invasive, ultrasound is also used to perform serial studies to monitor people who have small or medium-sized abdominal aortic aneurysms.

These serial ultrasound tests allow the doctor to judge whether the aneurysm is growing.

People who are thought to be suffering from rupture of an abdominal aortic aneurysm are usually critically ill with severe cardiovascular instability, and rapid surgery is critical. For these patients, a rapid bedside ultrasound test is usually done to quickly confirm the diagnosis, usually while they are being prepared for emergency surgery.

CT Scans

CT scans are used instead of or in addition to ultrasound tests in people who are thought to be likely to require surgical repair. These would include people who have symptoms suspected to be caused by an abdominal aortic aneurysm, or anyone with a known aneurysm that appears to be growing to a potentially dangerous size.

The CT scan not only shows the size and location of the aneurysm, but also shows important details about the surrounding structures and can reveal whether any sign of rupture or impending rupture are present.

Thoracic Aortic Aneurysms

In comparison to abdominal aortic aneurysms, thoracic aortic aneurysms tend to have more complex anatomy and tend much more often to involve critical surrounding structures such as the aortic valve, the large blood vessels that supply the brain, various nerves, and the airways.

The decision on whether to do surgery for a thoracic aneurysm depends on more than just the size and rate of growth of the aneurysm; it also depends on which other structures in the chest are being affected.

For this reason, when a thoracic aortic aneurysm is suspected, either a CT scan or an MRI study is usually performed because these studies show much more anatomic detail than an ultrasound study. If several serial studies are needed over time to help judge the optimal timing of surgery, MRI is typically used instead of CT scans, since MRI does not require radiation.

Screening

For Abdominal Aortic Aneurysms

It is distressingly common for the very first problem a person experiences with an abdominal aortic aneurysm to be the catastrophic symptoms of rupture. For this reason, screening studies using ultrasound are sometimes recommended for people with no symptoms, but who are judged to be at an elevated risk for an abdominal aortic aneurysm.

A screening ultrasound test for abdominal aortic aneurysm is generally recommended for the following people: 

  • People who have a pulsatile mass in the abdomen on physical examination.
  • Men over 65 years of age who have a history of smoking.
  • Men or women over 65 years of age who have a close relative who required surgery for, or died from the rupture of, an abdominal aortic aneurysm.

For Thoracic Aortic Aneurysms

Thoracic aortic aneurysms are often detected incidentally, either during a routine chest X-ray or during a cardiac ultrasound study. If a thoracic aortic aneurism is detected in this way, a subsequent chest CT or MRI study should be done to confirm the diagnosis and determine the extent of the aneurysm.

In certain high-risk people, screening examinations should be considered specifically to look for a thoracic aortic aneurysm, usually with either a CT scan or MRI. Indications for such a screening study include people with:

If either an abdominal aortic aneurysm or a thoracic aortic aneurysm is diagnosed with a screening study, and it is determined that early surgery is not required, close monitoring and periodic reassessments with imaging studies should be done to prevent rupture or other complications.

Sources:

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