CT angiography – chest

Computed tomography angiography – thorax; CTA – lungs; Pulmonary embolism – CTA chest; Thoracic aortic aneurysm – CTA chest; Venous thromboembolism – CTA lung; Blood clot – CTA lung; Embolus – CTA lung;  CT pulmonary angiogramCT angiography combines a CT scan with the injection of dye. This technique is able to create pictures of the blood vessels in the chest and upper abdomen. CT stands for computed tomography.

How the Test is Performed

You will be asked to lie on a narrow table that slides into the center of the CT scanner.

While inside the scanner, the machine’s x-ray beam rotates around you.

A computer creates multiple separate images of the body area, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional models of the chest area can be created by stacking the slices together.

You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short periods of time.

Complete scans usually take only a few minutes. The newest scanners can image your entire body, head to toe, in less than 30 seconds.

How to Prepare for the Test

Certain exams require a special dye, called contrast, to be delivered into the body before the test starts. Contrast helps certain areas show up better on x-rays.

• Contrast can be given through a vein (IV) in your hand or forearm. If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.
• Let your health care provider know if you have ever had a reaction to contrast. You may need to take medications before the test in order to safely receive it.
• Before receiving the contrast, tell your provider if you take the diabetes medication metformin (Glucophage). You may need to take extra precautions.

The contrast can worsen kidney function problems in people with poorly functioning kidneys.  Talk to your provider if you have a history of kidney problems.

Too much weight can damage the scanner. If you weigh more than 300 pounds (135 kilograms), talk to your provider about the weight limit before the test.

You will be asked to remove jewelry and wear a hospital gown during the study.

How the Test will Feel

The x-rays produced by the CT scan are painless. Some people may have discomfort from lying on the hard table.

If you have contrast through a vein, you may have a:

• Slight burning feeling
• Metallic taste in your mouth
• Warm flushing of your body

This is normal and usually goes away within a few seconds.

Why the Test is Performed

A chest CT angiogram may be done:

• For symptoms that suggest blood clots in the lungs, such as chest pain, rapid breathing, or shortness of breath
• After a chest injury or trauma
• Before surgery on the lung or chest
• To look for a possible site to insert a catheter for hemodialysis
• For swelling of the face or upper arms that cannot be explained
• To look for a suspected birth defect of the aorta or other blood vessels in the chest
• To look for balloon dilation of an artery (aneurysm)
• To look for a tear in an artery (dissection)

Normal Results

Results are considered normal if no problems are seen.

What Abnormal Results Mean

A chest CT may show many disorders of the heart, lungs, or chest area, including:

• Suspected blockage of the superior vena cava: This large vein moves blood from the upper half of the body to the heart.
• Blood clot(s) in the lungs.
• Abnormalities of the blood vessels in the lungs or chest, such as aortic arch syndrome.
• Aortic aneurysm (in the chest area) .
• Narrowing of part of the major artery leading out of the heart (aorta).
• Tear in the wall of an artery (dissection).
• Inflammation of the blood vessel walls (vasculitis).

Risks

Risks of CT scans include:

• Being exposed to radiation
• Allergic reaction to contrast dye
• Damage to kidneys from contrast dye

CT scans use more radiation than regular x-rays. Having many x-rays or CT scans over time may increase your risk for cancer. However, the risk from any one scan is small. You and your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.  Most modern scanners use techniques to use less radiation.

Some people have allergies to contrast dye. Let your provider know if you have ever had an allergic reaction to injected contrast dye.

• The most common type of contrast given into a vein contains iodine. If you have an iodine allergy, you may have nausea or vomiting, sneezing, itching, or hives if you get this type of contrast.
• If you absolutely must be given such contrast, your provider may give you antihistamines (such as Benadryl) or steroids before the test.
• The kidneys help remove iodine from the body. Those with kidney disease or diabetes may need to receive extra fluids after the test to help flush the iodine out of the body.

Rarely, the dye may cause a life-threatening allergic response called anaphylaxis. If you have any trouble breathing during the test, you should notify the scanner operator immediately. Scanners come with an intercom and speakers, so someone can hear you at all times.

Chest CT

Thoracic CT; CT scan – lungs; CT scan – chest

A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen.

How the Test is Performed

The test is done in the following way:

• You’ll likely be asked to change into a hospital gown.
• You lie on a narrow table that slides into the center of the scanner. Once you are inside the scanner, the machine’s x-ray beam rotates around you.
• You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short period of time.

The complete scan takes 30 seconds to a few minutes.

Certain CT scans require a special dye, called contrast, to be delivered into the body before the test starts. Contrast highlights specific areas inside the body and creates a clearer image. If your doctor requests a CT scan with intravenous contrast, you will be given it through a vein (IV) in your arm or hand. A blood test to measure your kidney function may be done before the test. This test is to make sure your kidneys are healthy enough to filter the contrast.

You may be given medicine to help you relax during the test.

How to Prepare for the Test

Some people have allergies to IV contrast and may need to take medicine before their test to safely receive this substance.

Contrast can be given in several ways, depending on the type of CT being performed.

• It may be delivered through a vein (IV) in your hand or forearm.
• It may be given through the rectum using an enema.
• You might drink the contrast before your scan. When you actually drink the contrast depends on the type of exam being done. The contrast liquid may taste chalky, although some are flavored to make them taste a little better. The contrast eventually passes out of your body through your stool.

If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.

If you weigh more than 300 pounds (135 kilograms), have your health care provider contact the scanner operator before the exam. CT scanners have a weight limit. Too much weight can damage the scanner’s working parts.

Because it is hard for x-rays to pass through metal, you will be asked to remove jewelry.

How the Test will Feel

Some people may have discomfort from lying on the hard table.

Contrast given through an IV may cause a slight burning sensation, a metallic taste in the mouth, and a warm flushing of the body. These sensations are normal and usually go away within a few seconds.

There is no recovery time, unless you were given medicine to relax. After a CT scan, you can go back to your normal diet, activity, and medicines.

Why the Test is Performed

CT quickly creates detailed pictures of the body. The test may be used to get a better view of the structures inside the chest. A CT scan is one of the best ways of looking at soft tissues such as the heart and lungs.

A chest CT may be done:

• After a chest injury
• When a tumor or mass (clump of cells) is suspected, including a solitary pulmonary nodule seen on a chest x-ray
• To determine the size, shape, and position of organs in the chest and upper abdomen
• To look for bleeding or fluid collections in the lungs or other areas
• To look for infection or inflammation in the chest
• To look for blood clots in the lungs
• To look for scarring in the lungs

What Abnormal Results Mean

Thoracic CT may show many disorders of the heart, lungs, or chest area, including:

•  A tear in the wall, an abnormal widening or ballooning, or narrowing of the major artery carrying blood out of the heart (aorta)
• Other abnormal changes of the major blood vessels in the lungs or chest
• The buildup of blood or fluid around the heart
• Lung cancer or cancer that has spread to the lungs from elsewhere in the body
• Collection of fluid around the lungs (pleural effusion)
• Damage to, and widening of the large airways of the lungs (bronchiectasis)
• Enlarged lymph nodes
• Lung disorders in which the lung tissues become inflamed and then damaged.
• Pneumonia
• Esophageal cancer
• Lymphoma in the chest
• Tumors, nodules, or cysts in the chest

Risks

CT scans and other x-rays are strictly monitored and controlled to make sure they use the least amount of radiation. CT scans use low levels of ionizing radiation, which has the potential to cause cancer and other defects. However, the risk from any one scan is small. The risk increases as many more studies are done.

In some cases, a CT scan may still be done if the benefits greatly outweigh the risks. For example, it can be more risky to not have the exam if your doctor thinks you might have cancer.

The most common type of contrast given into a vein contains iodine. If a person with an iodine allergy is given this type of contrast, nausea, sneezing, vomiting, itching, or hives may occur. In rare cases, the dye can cause a life-threatening allergic response called anaphylaxis. If you have any trouble breathing during the test, you should notify the scanner operator immediately. Scanners come with an intercom and speakers, so the operator can hear you at all times.

In people with kidney problems, the dye may have harmful effects on the kidneys. In these situations, special steps may be taken to make the contrast dye safer to use.

Chest MRI

Nuclear magnetic resonance – chest; Magnetic resonance imaging – chest; NMR – chest; MRI of the thorax; Thoracic MRI

A chest MRI (magnetic resonance imaging) scan is an imaging test that uses powerful magnetic fields and radio waves to create pictures of the chest (thoracic area). It does not use radiation (x-rays).

How the Test is Performed

The test is done in the following way:

• You may be asked to wear a hospital gown or clothing without metal fasteners (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images or be dangerous to have on in the scanner room.
• You lie on a narrow table, which slides into the large tunnel-shaped scanner.
• You must be still during the exam, because movement causes blurred images.

Some exams require a special dye called contrast. The dye is usually given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly. A blood test to measure your kidney function may be done before the test. This is to make sure your kidneys are healthy enough to filter the contrast.

During the MRI, the person who operates the machine will watch you from another room. The test most often lasts 30 to 60 minutes, but it may take longer.

How to Prepare for the Test

You may be asked not to eat or drink anything for 4 to 6 hours before the scan.

Tell your doctor if you are claustrophobic (afraid of closed spaces). You may be given a medicine to help you feel sleepy and less anxious. Your doctor may suggest an “open” MRI, in which the machine is not as close to your body.

Before the test, tell your health care provider if you have:

• Brain aneurysm clips
• Artificial heart valves
• Heart defibrillator or pacemaker
• Inner ear (cochlear) implants
• Kidney disease or are on dialysis (you may not be able to receive contrast)
• Recently placed artificial joints
• Vascular stents
• Worked with sheet metal in the past (you may need tests to check for metal pieces in your eyes)

The MRI contains strong magnets, so metal objects are not allowed into the room with the MRI scanner. This is because there is a risk that they will be drawn from your body toward the scanner. Examples of metal objects you will need to remove are:

• Pens, pocket knives, and eyeglasses
• Items such as jewelry, watches, credit cards, and hearing aids
• Pins, hairpins, and metal zippers
• Removable dental work

How the Test will Feel

An MRI exam causes no pain. If you have trouble lying still or are very nervous, you may be given medicine to relax you. Too much movement can blur MRI images and cause errors when the doctor looks at the images.

The table may be hard or cold, but you can ask for a blanket or pillow. The machine produces loud thumping and humming noises when turned on. You can wear earplugs to help reduce the noise.

An intercom in the room allows you to speak to someone at any time. Some MRIs have televisions and special headphones that you can use to help the time pass.

There is no recovery time unless you were given a medicine to relax. After an MRI scan, you can resume your normal diet, activity, and medicines.

Why the Test is Performed

A chest MRI provides detailed pictures of tissues within the chest area.

A chest MRI may be done to:

• Provide an alternative to angiography, or avoid repeated exposure to radiation
• Clarify findings from earlier x-rays or CT scans
• Diagnose abnormal growths in the chest
• Evaluate blood flow
• Show lymph nodes and blood vessels
• Show the structures of the chest from many angles
• See if cancer in the chest has spread to other areas of the body (this is called staging — it helps guide future treatment and follow-up and gives you an idea of what to expect in the future)
• Detect tumors

Normal Results

A normal result means your chest area appears normal.

What Abnormal Results Mean

An abnormal chest MRI may be due to:

• A tear in the wall, an abnormal widening or ballooning, or narrowing of the major artery carrying blood out of the heart (aorta)
• Other abnormal changes in the major blood vessels in the lungs or chest
• The buildup of blood or fluid around the heart or the lungs
• Lung cancer or cancer that has spread to the lungs from elsewhere in the body
• Cancer or tumors of the heart
• Cancer or tumors of the chest, such as a thymus tumor
• Disease in which the heart muscle becomes weakened, stretched, or has another structural problem ( cardiomyopathy )
• Collection of fluid around the lungs (pleural effusion)
• Damage to, and widening of the large airways of the lungs (bronchiectasis)
• Enlarged lymph nodes
• Infection of the heart tissue or heart valve
• Esophageal cancer
• Lymphoma in the chest
• Birth defects of the heart
• Tumors, nodules, or cysts in the chest

Risks

MRI uses no radiation. To date, no side effects from the magnetic fields and radio waves have been reported.

The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions to the substance rarely occur. However, gadolinium can be harmful to people with kidney problems who need dialysis. If you have kidney problems, tell your provider before the test.

The strong magnetic fields created during an MRI can cause heart pacemakers and other implants not to work as well. It can also cause a piece of metal inside your body to move or shift.

Considerations

Currently, MRI is not considered a valuable tool for spotting or monitoring slight changes in lung tissue. The lungs contain mostly air and are hard to image. CT scan tends to be better for monitoring these changes.

Disadvantages of MRI include:

• High cost
• Long length of the scan
• Sensitivity to movement

Thoracic spine CT scan

CAT scan – thoracic spine; Computed axial tomography scan – thoracic spine; Computed tomography scan – thoracic spine; CT scan – upper back

A computed tomography (CT) scan of the thoracic spine is an imaging method. This uses x-rays to rapidly create detailed pictures of the middle back (thoracic spine).

How the Test is Performed

You will lie on a narrow table that slides into the center of the CT scanner.

Once you are inside the scanner, the machine’s x-ray beam rotates around you. (Modern “spiral” scanners can perform the exam without stopping.)

A computer creates separate images of the body area. These are called slices. These images can be stored, viewed on a monitor, or printed on film. The slices together can create three-dimensional models of the body area.

You must be still during the exam. Movement will create blurred images. You may be told to hold your breath for short periods of time.

The scan should take only 10 to 15 minutes.

How to Prepare for the Test

Certain exams require a special dye, called contrast. Contrast is delivered into the body before the test starts. This helps certain areas show up better on the x-rays.

Contrast can be given in several ways. It may be given as an injection through:

• A vein (IV) in your hand or forearm.
• Your back into the space surrounding the spinal cord.

If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.

Before receiving the contrast, tell your health care provider if:

• You have ever had a reaction to contrast. You may need to take medicines before the test to safely receive the dye.
• You take the diabetes medicine metformin (Glucophage). You may need to take extra steps if you take this medicine.

Find out if the CT machine has a weight limit if you weigh more than 300 pounds (135 kilograms). Too much weight can cause damage to the scanner.

You will be asked to remove the jewelry and wear a hospital gown during the study.

How the Test will Feel

Some people may find it uncomfortable to lie on a hard table.

Contrast given through an IV may cause:

• Slight burning feeling
• Metallic taste in the mouth
• Warm flushing of the body

These feelings are normal and will often go away within a few seconds.

Why the Test is Performed

CT rapidly creates detailed pictures of the thoracic spine. The test may help diagnose or detect:

• Birth defects of the spine in children
• Bone fracture in the spine
• Arthritis of the spine
• The curvature of the spine
• Tumor of the spine
• Another spinal injury

Thoracic CT scan can also be used during or after:

• Myelography: An x-ray of the spinal cord and spinal nerve roots
• Discography: An x-ray of the disk

Normal Results

Results are normal if the thoracic spine looks normal.

What Abnormal Results Mean

Abnormal results may be due to:

• Birth defects of the spine
• Bone problems
• Fracture
• Herniated (slipped) disk
• Infection of the spine
• Narrowing of the spine ( spinal stenosis )
• Scoliosis
• Tumor

Risks

Risks of CT scans include:

• Exposure to radiation
• Allergic reaction to contrast dye

CT scans expose you to more radiation than regular x-rays. Having many x-rays or CT scans over time may increase your risk for cancer. However, the risk from any 1 scan is small. You and your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.

Some people have allergies to contrast dye.

The most common type of contrast given into a vein contains iodine. People with an iodine allergy may have:

• Nausea or vomiting
• Sneezing
• Itching or hives

In case you are allergic, your provider may give you antihistamines (such as Benadryl) or steroids before the test.

The kidneys help remove iodine from the body. People with kidney disease or diabetes may need to receive extra fluids after the test. This will help flush the iodine out of the body.

Rarely, the dye may cause anaphylaxis. Notify the scanner operator right away if you have any trouble breathing or swallowing. Scanners come with an intercom and speakers, so the operator can hear you at all times.

Considerations

The thoracic CT scan is good for evaluating large herniated disks. It can miss the smaller ones. This test with a myelogram will show a better image of the nerve roots and find smaller injuries.

Thoracic spine x-ray

Vertebral radiography; X-ray – spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films

A thoracic spine x-ray is an x-ray of the twelve chest (thoracic) bones (vertebrae). The vertebrae are separated by flat pads of cartilage called disks that provide a cushion between the bones.

How the Test is Performed

The test is done in a hospital radiology department or in the health care provider’s office. You will lie on the x-ray table in different positions. If the x-ray is checking for an injury, care will be taken to prevent further injury.

The x-ray machine will be moved over the thoracic area of the spine. You will hold your breath as the picture is taken, so that the picture will not be blurry. Usually 2 or 3 x-ray views are needed.

How to Prepare for the Test

Tell the provider if you are pregnant. Remove all jewelry.

How the Test will Feel

The test causes no discomfort. The table may be cold.

Why the Test is Performed

The x-ray helps evaluate:

• Bone injuries
• Cartilage loss
• Diseases of the bone
• Tumors of the bone

What Abnormal Results Mean

The test can detect:

• Bone spurs
• Deformities of the spine
• Disk narrowing
• Dislocations
• Fractures
• Thinning of the bone ( osteoporosis )
• Wearing away (degeneration) of the vertebrae

Risks

There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits.

Pregnant women and children are more sensitive to the risks of x-rays.

Considerations

The x-ray will not detect problems in the muscles, nerves, and other soft tissues, because these problems cannot be seen well on an x-ray.

FAQ