WHAT IS CT SCANNING OF THE BODY?

CT scanning is a noninvasive medical test that helps physicians diagnose medical conditions.
CT scanning combines special x-ray equipment with sophisticated computers to produce multiple images or pictures of the inside of the body. These cross-sectional images of the area being studied can then be viewed on a computer monitor, printed or transferred to a CD.
CT scans of internal organs; bones, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.
Using specialized equipment and expertise to create and interpret CT scans of the body, radiologists can more easily diagnose problems such as cancers, cardiovascular disease, infectious disease, appendicitis, trauma and musculoskeletal disorders.

HOW SHOULD I PREPARE?

You should wear comfortable, loose-fitting clothing to your exam. You will be given a gown to wear during the procedure.
Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing metal underwire. 
You should inform the technologist if you have a pacemaker. Pacemakers do not hinder the use of CT as in MRI as long as the scanner will not be taking images repeatedly over the area of the pacemaker device in the upper chest. 
You may be asked not to eat or drink anything for a few hours (usually 6-8hours) beforehand, especially if a contrast material will be used in your exam. You should inform your physician of all medications you are taking and if you have any allergies. If you have a known allergy to contrast material, or "dye," your doctor may prescribe medications (usually a steroid) to reduce the risk of an allergic reaction. These medications generally need to be taken few hours prior to administration of contrast material. 

Women should always inform their physician and the CT technologist if there is any possibility that they may be pregnant.

WHAT DOES THE EQUIPMENT LOOK LIKE?

The CT scanner is typically a large, box-like machine with a hole, or short tunnel,

in the center. You will lie on a narrow examination table that slides into and out of

this tunnel. Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry.

The computer workstation that processes the imaging information is located in a separate control room, where the technologist operates the scanner and monitors your examination in direct visual contact and usually with the ability to hear and

talk to you with the use of a speaker and microphone.

HOW IS THE CT SCAN PERFORMED?

The technologist begins by positioning you on the CT examination table, usually lying flat on your back or less commonly on your side or on your stomach. Straps and pillows may be used to help you maintain the correct position and to help you remain still during the exam. Depending on the part of the body being scanned, you may be asked to raise your arms over your head.

Many scanners are fast enough that children can be scanned without sedation.
In special cases, sedation may be needed for children who cannot hold still. Motion will degrade the quality of the examination the same way that it affects photographs.
If contrast material is used, it will be swallowed, injected through an intravenous line (IV) or administered by enema, depending on the type of examination.
Next, the table will move quickly through the scanner to determine the correct starting position for the scans. Then, the table will move slowly through the machine as the actual CT scanning is performed. 
You may be asked to hold your breath during the scanning. Any motion, whether breathing or body movements, can lead to articats on the images. 
When the examination is completed, you will be asked to wait until the technologist verifies that the images are of high quality for accurate interpretation.
The CT examination is usually completed within 30 minutes. 

WHAT WILL I EXPERIENCE DURING AND AFTER THE PROCEDURE?

CT exams are generally painless, fast and easy.
Though the scanning itself causes no pain.
If an intravenous contrast material is used, you will feel a pin prick when the needle is inserted into your vein. You will likely have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in your mouth that lasts for at most a minute or two.
If the contrast material is swallowed, you may find the taste mildly unpleasant; however, most patients can easily tolerate it. 
If your contrast material is given by enema, be patient, as the mild discomfort will not last long.
You will be alone in the exam room during the CT scan, however, the technologist will always be able to see, hear and speak with you through a built-in intercom system.
With pediatric patients, a parent may be allowed in the room but will be required to wear a lead apron to minimize radiation exposure.
After a CT exam, you can return to your normal activities. If you received contrast material, you may be given special instructions.

WHO INTERPRETS THE RESULTS AND HOW DO I GET THEM?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a detailed report to the physician who referred you for the exam. The referring physician will discuss the results with you.
 

WHAT ARE TH EBENEFITS VERSUS RISKS?
BENEFITS

1. CT scanning is painless, noninvasive and accurate.

2. A major advantage of CT is its ability to image bone, soft tissue and blood vessels all at the same time.

3. Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissues as well as the lungs, bones, and blood vessels.

4. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.

5. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.

6. CT can be performed if you have an implanted medical device of any kind, unlike MRI.

7. CT imaging provides a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones.

8. A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy.

9. No radiation remains in a patient's body after a CT examination.

RISKS
When a CT scan is recommended by your doctor, the expected benefit of this test outweighs the potential risk from radiation. You are encouraged to discuss the risks versus the benefits of your CT scan with your doctor.

1. Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant.  

2. CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.

3. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 hours after contrast medium is given. 

4. The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.

5. Because children are more sensitive to radiation, they should have a CT exam only if it is essential for making a diagnosis and should not have repeated CT exams unless absolutely necessary. CT scans in children should always be done with low-dose technique.

    

WHAT ARE THE LIMITATIONS OF CT SCAN OF THE BODY?

Soft-tissue details in areas such as the brain, internal pelvic organs, and joints (such as knees and shoulders) can often be better evaluated with magnetic resonance imaging (MRI).
In pregnant women, other imaging exams not involving radiation, such as ultrasound or MRI, is preferred if they are likely to be as good as CT in diagnosing your condition.
A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit—usually 180kg—for the moving table. 

CT OF THE ABDOMEN AND PELVIS

WHAT ARE SOME COMMON USES OF THE PROCEDURE?

CT IMAGING IS:

1. One of the best and fastest tools for examining the abdomen and pelvis because it provides detailed, cross-sectional views of all types of tissue.

2. Used to examine patients with severe injuries from accidents such as a motor vehicle accident.

3. Performed on patients with acute symptoms such as acute abdominal pain.

4. Often the best method for detecting many different cancers, including liver, kidney and pancreatic cancer, since the image allows a physician to confirm the presence of a tumor and measure its size, precise location and the extent of the tumor's involvement with other nearby tissue.

5. Plays a significant role in the detection, diagnosis and treatment of vascular diseases as abdominal aortic aneurysms (AAA).

6. Guide biopsies and other procedures such as abscess drainages and minimally invasive tumor treatments.

7. Plan for and assess the results of surgery, such as organ transplants or gastric bypass.

8. Measure bone mineral density for the detection of osteoporosis.

In pediatric patients, CT is rarely used For children, CT imaging is more often used to evaluate:

CT scan showing the liver and spleen.

CT slice through the mid-abdomen showing multiple normal-appearing

organs, which are labeled.

CT scan of a normal appendix in the right lower abdomen. The appendix

normally connects with the right colon and contains air (this appears black

on the scan).

Air in the appendix excludes appendicitis since this means that the appendix

is not obstructed or inflammed.  

Appendicitis: The appendix is distended and inflammed.

Normal CT of the abdomen. A CT 'slice' through the upper abdomen of

a child illustrates the normal appearance of both kidneys, the liver and

gallbladder.

CT UROGRAPHY

Computed tomography (CT) urography use CT  after intravenous contrast material to obtain images of the urinary tract. CT urography (CTU) is used as primary imaging techniques to evaluate patients with blood in the urine (hematuria), follow patients with prior history of cancers of the urinary collecting system and to identify abnormalities in patients with recurrent urinary tract infections. In addition to imaging the urinary tract, CT urography can provide valuable information about other abdominal and pelvic structures and diseases that may affect them.

WHAT ARE THE COMMON USES OF THE PROCEDURE?

Urography images are used to detect abnormalities in the urinary tract, including the kidneys, bladder and ureters, including:

A 3D reconstructed CT view of the kidneys and ureters, which connect the

kidneys to the bladder. Part of the ribs, spine and pelvis are included in this image.

Three-dimensional (3-D VR) image of a three-phase CT urogram

showing opacified collecting systems, ureters and bladder.  

WHAT IS CT SCANNING OF THE CHEST?

WHAT ARE SOME COMMON USES OF THE PROCEDURE?

1. Evaluate injury to the chest, including the blood vessels, lungs, ribs and spine.

2. Chest CT can demonstrate various lung disorders, such as:

   1. Lung cancer: Detect and evaluate the extent of tumors that arise in the chest, or tumors that have spread there from other parts of the body.

   2. Old or new pneumonia.

   3. Tuberculosis.

   4. Emphysema and obstructive lung disease (COPD)

   5. Bronchiectasis

   6. Inflammation or other diseases of the pleura.

   7.Diffuse interstitial lung disease.

   8. Congenital abnormalities.

A CT angiogram (CTA) may be performed to evaluate the blood vessels (arteries and veins) in the chest. This involves the rapid injection of an iodine-containing fluid (contrast material) into a vein while obtaining CT images.  

Potential Lung Cancer Screening Tool:
Because CT scans are able to detect even very small nodules in the lung, chest CT is especially effective for diagnosing lung cancer at its earliest, most curable stage.

CT of the lungs, window level set to demonstrate the vessels and air ways

( not intended to demonstrate the heart, spine muscles etc. ).This is used

to look for things like pneumonia or lung cancer.  

WHAT IS THE CT SCAN OF THE HEAD?

WHAT ARE SOME COMMON USES OF THE PROCEDURE?

CT scanning of the head is typically used to detect:

1. Bleeding, brain injury and skull fractures in patients with head injuries.

2. Bleeding caused by a ruptured or leaking aneurysm in a patient with a sudden severe headache.

3. A blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke.

4. Brain tumors.

5. Enlarged brain cavities (ventricles) in patients with hydrocephalus.

6. Diseases or bony malformations of the skull.

CT scanning is also performed to:

1. Evaluate the extent of bone and soft tissue damage in patients with facial trauma, and planning surgical reconstruction.

2. Diagnose diseases of the temporal bone on the side of the skull, which may be causing hearing problems.

3. Determine whether inflammation or other changes are present in the paranasal sinuses.

4. Plan radiation therapy or cancer of the brain or other tissues.

5. Assess aneurysms or arteriovenous malformationthrough a technique called CT angiography.

Two different views of CT brain angiogram reveal an aneurysm (arrows)

arising from the basilar artery.

Normal head CAT scan with intravenous contrast.

CT SCAN OF THE SINUSES:

A CT scan of the face produces images that also show a patient's paranasal sinus cavities. The paranasal sinuses are hollow, air-filled spaces located within the bones of the face and surrounding the nasal cavity, a system of air channels connecting the nose with the back of the throat. There are four pairs of sinuses, each connected to the nasal cavity by small openings.

WHAT ARE SOME COMMON USES OF THE PROCEDURE?

CT of the sinuses primarily is used to:

CT scan - direct coronal (from the top of the head) view of the ethmoid

and maxillary sinuses.