Canada Vascular

Aortic Aneurysms (TAA & AAA)

Background

Diagnosis

Screening

Treatment Options

Common Questions & Answers

Glossary

Bibliography

 

 


Diagnosis

How is AAA Diagnosed?

In some, but not all cases, AAA can be diagnosed by a physical examination in which the doctor feels the aneurysm as a soft mass in the abdomen (about the level of a belly button) that pulses with each heartbeat.

The most common test to diagnose AAA is ultrasound. Ultrasound is also the safest and most common method to screen for AAA. Other methods for determining the aneurysms' size are CT scan (computerized tomography), MRI (magnetic resonance imaging), and angiogram (real time x-rays).

 

Ultrasound

CT Scan

MRA Scan

Angiogram

 

 

What is Ultrasound?

Ultrasound is a painless examination in which a device (a transducer) about the size of a computer mouse is passed over the abdomen. Sound waves are computerized to create "pictures" of the aorta and detect the presence of AAA. Ultrasound is the safest and least invasive method to screen for AAA. Duplex ultrasound combines Doppler and conventional ultrasound to allow physicians to see the structure of your blood vessels. Duplex ultrasound shows how blood is flowing through your vessels and measures the speed of the flow of blood.

Conventional ultrasound uses sound waves higher than the human ear can detect that bounce off of blood vessels. A computer converts the sound waves into two-dimensional, black and white moving images.

Doppler ultrasound measures how sound waves reflect off of moving objects. A wand bounces short bursts of sound waves off of red blood cells and sends the information to a computer. Doppler ultrasound produces two-dimensional color images that show if blood flow is affected by problems in the blood vessels.

When performing duplex ultrasound, your physician uses the two forms of ultrasound together. The conventional ultrasound shows the structure of your blood vessels and Doppler ultrasound shows the movement of your red blood cells through the vessels. Duplex ultrasound produces images that can be color coded to show physicians where your blood flow is severely blocked.


You may have the test performed in an ultrasound lab. The lab may be part of the physician's office or it may be in a hospital. In some cases your vascular physician may perform the test. Usually, however, a specially trained vascular ultrasound technologist performs duplex ultrasound.

The test usually lasts about 10 minutes.

How Do I Prepare?

For most types of duplex ultrasound not involving the abdomen, you will not have to follow any special instructions. Your physician or the center performing the test may have specific instructions for a particular type of duplex ultrasound. For instance, you may have to fast for 4-6 hours before having an abdominal ultrasound. Ultrasound waves cannot break through gas in the bowels or air in the lungs.

What Happens During a Duplex Ultrasound?

Before the test begins, your physician or the technician will ask you to lie on the table with your head slightly elevated. The technician will also ask you to lie still because any movement could change the image. The technician then spreads a special gel over the area that he or she will examine. The technician presses the ultrasound wand against your skin and moves it back and forth. As the wand moves back and forth, it sends the information to the computer that produces the images. During the test, you may hear a whooshing sound, which is the sound that the ultrasound machine makes to represent your blood moving through your body. A screening ultrasound at The Toronto Endovascular Centre takes approximately 10 minutes or less.

What Can I Expect After a Duplex Ultrasound?

There are no special instructions for you to follow after the test. You may resume all of your normal activities.

Are there any Complications?

Ultrasound is a non invasive test with no complications.

What is a CT Scan?

Computerized tomography scanning, also called CT or CAT scanning, is a test that uses x rays and computers to create detailed images of the internal structures of the body. These images, known as CT scans, show cross-sections, or slices, of your body. CT scanning is painless and usually takes fewer than 30 minutes.

CT scans can show the anatomy of a variety of sections of the body, including:

  • Your abdomen, which contains important blood vessels like your abdominal aorta (your main artery) and your liver and kidneys
  • Your chest
  • Your neck
  • Your arms or legs
  • Your brain

Your physician might order a CT scan to help diagnose vascular conditions, tumors, infections, and other conditions.

During a CT scan, you lie down on a table. The table passes through a donut-shaped device. Inside the device, a machine takes x rays in arcs around the area of your body being examined. Tissues of varying densities absorb these x rays. The computer assigns these densities different numerical values and then plots an image based on these values, mainly in shades of gray. In general, CT scans display bones as white, gases and liquids as black, and tissues as varying shades of gray.

Physicians may find it helpful to compare two CT scans of the same anatomical area. One without the administration of a dye-like material called contrast, and one with this contrast material. Contrast material makes hollow or fluid-filled structures more visible and highlights the presence and extent of abnormalities, such as blood vessel abnormalities, cysts, tumors, and abscesses.

How Do I Prepare?

If your test will include contrast, your physician will ask you to avoid foods and liquids for about 4 hours before the test. If you will be having abdominal contrast images, you will drink a liquid version of the contrast agent 1 to 2 hours before your test.

Before the test is performed, you change into a hospital gown and remove all jewelry and other metal objects, which interfere with x rays. If you will be receiving a head CT scan, you will be able to wear street clothes.

If you fear being in small, confined spaces, your physician may give you a sedative to help you relax. If you receive a sedative, you should arrange for a ride home after the test.

Am I at Risk for Complications?

Because CT scanning is an x ray test, it sends radiation through your body. The amount of radiation is small, but radiation can damage body cells.

Contrast material carries a slight risk of causing an allergic reaction. If you know that you are allergic to contrast material or dye, let your physician know before you receive the contrast material. The contrast material is also eliminated by the kidneys and can affect their function, especially if you have kidney problems already.

You May Be Unsuited for a CT Scan if You:

  • Are pregnant, because radiation may harm the fetus
  • Have an allergy to contrast dye
  • Have unstable vital signs
  • Weigh more than 300 pounds, because the table cannot support the weight
  • Have kidney problems

What Happens During a CT Scan?

If the physician chooses to perform CT scanning with contrast, he or she will inject the contrast material into a vein in your arm or hand. The contrast material may make your feel flushed, warm, and mildly sick to your stomach. This will only last for about 30 seconds.

You will lie still on the scan table that slides into the gantry, the donut-shaped device that houses the scanning equipment. The machine is quiet and relatively open; only the part of the body being examined lies inside the gantry. As a medical technician operates the scanning machine in another room, he or she watches and speaks to you through speakers in the CT scan room.

An x ray tube slides around the gantry, passing narrow beams of low-dosage x rays in an arc over the body. These beams reflect onto a detector positioned opposite the x ray source. After the x ray source completes an arc, the scanning table moves forward a small distance and the x ray source transmits another arc of x rays. The detector transmits the x ray energy to a computer, which transforms the information about the reflected energy into an image. To create images from different angles, the technician adjusts the position of the scanning table.

You must remain still as the CT scanning machine operates. The technician may ask you to hold your breath for 20 seconds at a time, because even the motion of breathing can blur the images. If you are being scanned for brain images, you may rest your head on a rubber cap within a water-filled box or within a stationary head brace.

The entire procedure usually takes 15 to 45 minutes.

What Can I Expect After a CT Scan?

There are no restrictions after a CT scan and you can resume normal activities immediately.

If your physician gave you a contrast agent, you should drink fluids following the test to speed excretion of the agent and to guard against dehydration.

Are there any Complications?

The most serious complication of CT scanning is an allergic reaction to the contrast dye. Reactions usually occur immediately and include flushing, itching, or difficulty breathing or swallowing. Notify your physician if you experience any of these symptoms. Sometimes contrast dye leaks under your skin at the injection site. This can cause redness, swelling, or pain.

What is Magnetic Resonance Angiography?

"Magnetic resonance angiography (MRA) uses magnetic fields and radio waves to produce two-dimensional or three-dimensional images of the structures inside your body, such as blood vessels. MRA is also sometimes referred to as MRI (magnetic resonance imaging) scanning. MRA helps your physician diagnose the following conditions:"

  • Bulges in your aorta, called aneurysms
  • Tears in your aorta, called dissections
  • Problems with your heart that you may be born with, called congenital heart disorders
  • Narrowing of the arteries in and around your kidneys, called renal artery stenosis
  • Inflammation in your blood vessels, called vasculitis
  • Hardening of the arteries (called atherosclerosis) involving the legs or arms
  • Blockages in the major arteries that supply blood to your brain, called carotid artery disease

The MRA equipment consists of a table that slides in and out of a donut-shaped machine. A computer attached to the machine processes radio waves and magnetic fields to create two-dimensional or three-dimensional images.

MRA not only helps your physician diagnose your condition, it also helps him or her plan treatment. MRA also may, in some circumstances, have advantages that other tests do not. For instance, MRA does not require X-ray exposure to detect narrowing of arteries, unlike computed tomography (CT) scans or angiograms.

How Do I Prepare?

Your physician may ask you not to eat 4 to 6 hours before the test, but usually no other preparation is necessary.

You May not Be Eligible for an MRA if You:

  • Weigh more than 300 pounds
  • Have a pacemaker or other metallic devices inside your body, such as joints, pins, clips, or valves
  • Are on continuous life support devices, such as oxygen
  • Are pregnant
  • Are claustrophobic
  • Are extremely anxious, confused, or agitated

If you are claustrophobic, your physician may recommend an open MRA.

What Happens During an MRA?

Your physician will direct you to a special lab or room where a technician will perform the test. The technician will instruct you to change into a hospital gown and remove any jewelry or metallic objects. The technician may give you a sedative to make sure that you lie still during the procedure.

The technician will ask you to lie on the MRA table. The table slides slowly through a hollow, donut-shaped chamber that exposes you to magnetic fields and pulses of radio waves. These magnetic fields and radio waves are harmless and painless. The only discomfort that you may feel will be from lying still on the hard table in an enclosed area.

During the test, the technician may speak to you through a speaker that is inside the MRA room.

Sometimes the technician may inject a contrast dye into your hand or forearm to improve the quality of the images.

An MRA lasts between 30 to 90 minutes.

What Can I Expect After an MRA?

Your physician will instruct you to arrange for a ride home if you receive a sedative.

Are there any Complications?

Complications from an MRA, such as a reaction to the contrast dye, are very unusual.

What is an Angiogram?

An angiogram uses x rays to view your body’s blood vessels. Physicians often use this test to study narrow, blocked, enlarged, or malformed arteries in many parts of your body, including your brain, heart, abdomen, and legs. When the arteries are studied, the test is also called an arteriogram. If the veins are studied, it is called a venogram.

To create the x ray images, your physician will inject a dye through a thin, flexible tube, called a catheter. He or she threads the catheter into the desired artery from an access point. The access point is usually in your groin but it can also be in your arm. This dye, called contrast, makes blood vessels visible on an x ray. Your physician will recommend an angiogram to diagnose vascular conditions, including:

  • Blockages of the arteries outside of your heart, called peripheral artery disease (PAD)
  • Enlargements of the arteries, called aneurysms
  • Kidney artery conditions, called renovascular conditions
  • Problems in the arteries that branch off the aorta, called aortic arch conditions
  • Malformed arteries, called vascular malformations

Sometimes physicians can also treat a problem during an angiogram. For instance, your physician may dissolve a clot that he or she discovers during the test. A physician may also perform an angioplasty and stenting procedure to clear blocked arteries during an angiogram, depending on the location and extent of the blockage. An angiogram can also help your physician plan operations to repair the arteries for more extensive problems.

How Do I Prepare?

Your physician will perform blood tests to determine your blood’s ability to clot and to assess your kidney function. Based on the test results, your physician may instruct you to stop taking aspirin or other drugs that prevent clotting. Your physician will also tell you which medications you should continue to take. Usually your physician will ask you not to eat or drink anything within 6 hours of your angiogram. Because you shouldn't drive after an angiogram, you should arrange for a ride home.

Am I at Risk for Complications?

Blood clotting problems, kidney problems, and advanced age can increase your risk for developing complications during and after an angiogram. Allergies can increase your risk of a reaction to the contrast dye.

What Happens During an Angiogram?

Your test will take place in a room equipped with a specialized x ray machine. Your physician will insert an IV to provide you with fluids and medications. Your physician will choose where to insert the catheter, usually into an artery in your groin or your elbow. Before the insertion, he or she will clean your skin and shave any hair to reduce your risk of infection. Your physician numbs your skin with a local anesthetic and then makes a tiny puncture to reach the artery below. He or she punctures your artery with a hollow needle, advances a thin wire through the needle, threads a catheter over the wire, and guides it to the desired location. Your physician takes x rays that are projected on a video screen to see the catheter as it moves through your arteries.

Once your physician has positioned the catheter properly, he or she injects the contrast dye. The contrast causes a brief, mild warm feeling as it enters your bloodstream. Your physician takes more x ray images to see how the contrast is flowing through your arteries. During the test, your physician may ask you to hold your breath for about 5 to 15 seconds. In addition, your physician may ask you to lie perfectly still to prevent sudden movements from blurring the x ray pictures.

When the test is over, your physician will remove the catheter and press the insertion site for 10 to 20 minutes to help stop bleeding.

Angiograms generally take about 1 hour to complete if only xrays are required. It may take longer if your physician also performs angioplasty and stenting.

What Can I Expect after an Angiogram?

After the test, the medical team will monitor you for about 6 hours. During this time, you should keep the arm or leg that was punctured straight to minimize bleeding from the puncture site. You will also be asked to drink fluids to prevent dehydration and flush the dye from your kidneys. Once any bleeding from the insertion site has stopped and your vital signs are normal, your physician will tell you that you can leave.

At home, you can eat normally, but you should continue drinking extra fluids for 1 to 2 days. For at least 12 hours after the angiogram, avoid physical activities such as climbing stairs, driving, and walking. You should be able to resume normal activities within a day or two of the procedure.

Are there any Complications?

Complications from angiography include bleeding, pain, or swelling where the catheter was inserted, and pain, numbness, or coolness in your arm or leg. Bruising at the puncture site is common and usually resolves on its own.

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