The aorta is the main blood vessel coming off of the heart to deliver blood to the rest of the body. It leaves the left side of the heart and travels up into the chest then curves down, enters the abdominal cavity, and continues on until splitting into the left and right iliac arteries in the pelvis. An aortic aneurysm occurs when the tissues of the wall weaken, causing it to bulge out. It can bulge out as a sac-like extension or the entire artery can expand in diameter. Various tests are used to establish the diagnosis of aortic aneurysm and swiftly initiate treatment.
X-Ray
Many aneurysms are without symptoms. Routine chest X-rays are one way in which asymptomatic aneurysms may be found. These chest X-rays may be performed for other reasons, such as before surgery or as part of a physical. The middle of the chest may appear widened on X-ray, among other clues on the film. However, an X-ray is not very sensitive for finding aneurysms in the chest.
CT Scan and MR Imaging
X-ray computed tomography, also known as CT scan or CAT scan, and magnetic resonance imaging, or MRI, are useful methods for diagnosing and characterizing aortic aneurysms, particularly in the chest. CT scan uses a series of X-rays that a computer merges together to obtain a high resolution image of the anatomy of the lesion and other organs in the body. MRI uses magnetic fields to do the same.
Ultrasound and Echocardiography
Both ultrasound and echocardiography use sound waves to produce pictures of the blood vessels and other organs. Echocardiography images the chest, and may be done with a probe placed outside the chest wall, called a transthoracic echocardiogram or TTE. If the image is not clear enough, a transesophageal echocardiogram, or TEE, can be used, during which the probe is placed in the esophagus through the mouth. By placing a probe over the abdomen, an ultrasound is very useful for following an abdominal aortic aneurysm.
Contrast Angiography
Though it is less often used, contrast angiography may be used to define the anatomy of the aneurysm and nearby vessels. In this technique, dye is injected into the blood vessels and X-rays are taken of the lesion. Disadvantages include possible kidney damage from the dye or allergic reactions.
References
- "American Journal of Medicine"; Chest radiography for the diagnosis of acute aortic syndrome.; Von Kotolisch et al.; 2004
- "Circulation"; Thoracic and abdominal aortic aneurysms; Isselbacher; 2005
- MayoClinic.com: Aortic Aneurysm
