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Imaging & Radiology at Baylor

Baylor provides a full array of diagnostic and therapeutic services at our hospitals and imaging centers across the Dallas/Fort Worth Metroplex. Learn important information about the procedures listed below, including why the tests are needed, what to expect and results and risks for each. 

Bone Density TestExamen de la Densidad ósea

Bone Density Test

Some women are at greater risk for osteoporosis — the decrease of bone mass and density as a result of the depletion of bone calcium and protein — than others. Your doctor can help you determine your risk of developing osteoporosis by taking your personal and family medical history, and by performing a bone density test or bone mass measurement.

What is a bone density test?

A bone density test, also known as bone mass measurement or bone mineral density test, measures the strength and density of your bones as you approach menopause and, when the test is repeated sometime later, can help determine how quickly you are losing bone mass and density. These tests are painless, noninvasive, and safe. They compare your bone density with standards for what is expected in someone of your age, gender, and size, and to the optimal peak bone density of a healthy young adult of the same gender. Bone density testing can help to:

  • Detect low bone density before a fracture occurs.

  • Confirm a diagnosis of osteoporosis if you have already fractured.

  • Predict your chances of fracturing in the future.

  • Determine your rate of bone loss and/or monitor the effects of treatment if the test is conducted at intervals of a year or more.

What are some reasons for having a bone density test?

If you have 1 or more of the following risk factors for osteoporosis, you may want to consider having a bone density test:

  • You have already experienced a bone fracture that may be the result of thinning bones.

  • Your mother, grandmother, or another close relative had osteoporosis or bone fractures.

  • Over a long period of time, you have taken medication that accelerates bone loss, such as corticosteroids for treating rheumatoid arthritis or other conditions, or some anti-seizure medications.

  • You have low body weight, a slight build, or a light complexion.

  • You have a history of cigarette smoking or heavy drinking.

Bone Density Measurement

Bone density measurements are preformed in order to find or confirm a diagnosis of osteoporosis.

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What is a myelogram?

A myelogram is a diagnostic imaging procedure done by a radiologist. It uses a contrast dye and X-rays or computed tomography (CT) to look for problems in the spinal canal, including the spinal cord, nerve roots, and other tissues. It is also known as myelography.

The contrast dye is injected into the spinal column before the procedure. The contrast dye appears on an X-ray screen, allowing the radiologist to see the spinal cord, subarachnoid space, and other nearby structures more clearly than with standard X-rays of the spine.

The radiologist will also use a CT scan when doing a myelogram. A CT or CAT scan is a diagnostic imaging procedure using a combination of X-rays and computer technology to produce horizontal, or axial, images of the body. These images, called slices, show detailed images of the spinal canal. CT scans provide more detail than standard X-rays.

Anatomy of the spinal column
Click image to enlarge

Anatomy of the spine

The spinal column is made up of 33 vertebrae that are separated by spongy disks and classified into distinct areas.

  • The cervical area consists of seven vertebrae in the neck.

  • The thoracic area consists of 12 vertebrae in the chest area.

  • The lumbar area consists of five vertebrae in the lower back area.

  • The sacrum has five, small fused vertebrae.

  • The four coccygeal vertebrae fuse to form one bone, called the coccyx or tailbone.

The spinal cord, a major part of the central nervous system, is located in the vertebral canal and reaches from the base of the skull to the upper part of the lower back. The bones of the spine and a sac containing cerebrospinal fluid surround it. The spinal cord carries sensory and movement signals to and from the brain and controls many reflexes.

Why might I need a myelogram?

A myelogram may be performed to assess the spinal cord, subarachnoid space, or other structures for abnormalities, particularly when another type of examination, such as a standard X-ray, is inconclusive. Myelograms may be used to evaluate many diseases, including, but not limited to, the following:

  • Herniated discs (discs that bulge and press on nerves and/or the spinal cord)

  • Spinal cord or brain tumors

  • Infection and/or inflammation of tissues around the spinal cord and brain

  • Spinal stenosis (degeneration and swelling of the bones and tissue around the spinal cord that make the canal narrow)

  • Ankylosing spondylitis (a disease that affects the spine, causing bones to grow together)

  • Bone spurs

  • Arthritis discs

  • Degenerative disc disease 

  • Cysts (benign capsules that may be filled with fluid)

  • Tearing away or injury of spinal nerve roots

  • Arachnoiditis (inflammation of a delicate membrane covering the brain)

There may be other reasons for your doctor to recommend a myelogram.

What are the risks of a myelogram?

You may want to ask your doctor about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your radiation exposure, such as previous scans and other types of X-rays, so that you can tell your doctor. Risks associated with radiation exposure may be related to the cumulative number of X-ray examinations and/or treatments over a long period of time.

If you are pregnant or think you may be, tell your doctor. Radiation exposure to the fetus may cause birth defects.

Because a contrast dye is used during the procedure, there is risk of allergic reaction to the substance. You will need to let your doctor know if you have ever had a reaction to any contrast.

Because the contrast is injected into the cerebrospinal fluid which also surrounds the brain, there is a small risk of seizure after the injection.  Some medications may place you at greater risk for seizure and you may be asked to stop taking a medication for 48 hours before and after the study.

Because this procedure involves a lumbar puncture, the following potential complications may occur:

  • A small amount of CSF can leak from the needle insertion site. This can cause headaches after the procedure. If there is a persistent leak the headache can be severe.

  • There is a slight risk of infection because the needle breaks the skin's surface, providing a possible portal of entry for bacteria.

  • A temporary numbness to the legs or lower back pain may be experienced.

  • There is a risk of bleeding in the spinal canal.

  • There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.

How do I prepare for a myelogram?

  • Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.

  • You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.

  • Generally, fasting is required prior to administering contrast. Your doctor will instruct you prior to the procedure of any necessary fasting requirements.

  • Notify the radiologist if you have ever had a reaction to any contrast or if you are allergic to iodine.

  • Notify the radiologist if you are pregnant or suspect that you may be pregnant.

  • Notify your doctor of all medications (prescribed and over-the-counter) and herbal supplements that you are taking. Many medications can cause problems with myelography. You will be screened for any of these before your test. You may be asked to stop some of your medications prior to the procedure.

  • Sedation may be given prior to the procedure to help you relax.

  • Notify the doctor if you have a history of seizures or if you are taking any prescribed medications for seizures.

  • Notify your doctor if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.

  • If the procedure is performed on an outpatient basis, you may be asked to remain in the hospital for several hours following the procedure. You should plan to have another person drive you home.

  • Based on your medical condition, your doctor may request other specific preparation.

Lumbar puncture or spinal tap
Click image to enlarge

What happens during a myelogram?

A myelogram may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.

Generally, a myelogram follows this process:

  1. You will be asked to remove any clothing, jewelry or other objects that may interfere with the procedure.

  2. You will be given a gown to wear.

  3. You will be reminded to empty your bladder prior to the start of the procedure.

  4. During the procedure, you will lie on your stomach on a padded table.

  5. Your back will be cleaned with an antiseptic solution and draped with sterile towels.

  6. The radiologist will numb the skin by injecting a local anesthetic that numbs the site. This injection may sting for a few seconds, but makes the procedure less painful.

  7. A needle will be inserted through the numbed skin and into the subarachnoid space where the spinal fluid is located. You may feel some pressure while the needle is inserted, but you must stay still during the insertion of the needle.

  8. The radiologist will remove some of the spinal fluid from the spinal canal. Next, a portion of contrast dye will be injected into the spinal canal through the needle. You may feel a warming sensation when the contrast dye is injected.

  9. The X-ray table will be tilted in various directions to allow gravity to move the contrast dye to different areas of your spinal cord. You will be held in place by a special brace or harness. More contrast may be given during this process through the secured lumbar puncture needle.

  10. The needle is removed and the X-rays or CT scan pictures are taken.

  11. Tell the radiologist right away if you feel any numbness, tingling, headache, or lightheadedness during the procedure.

You may experience discomfort during the myelogram. The radiologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after the procedure?

You should remain in the lying position for several hours after the procedure to reduce your risk of developing a CSF leak.   

You will be asked to drink additional fluids to rehydrate after the procedure. This helps to replace the spinal fluid that was withdrawn and reduces the chance of developing a headache.

A nurse will monitor your vital signs (blood pressure, temperature, pulse, and respirations) frequently after the test. Analgesic agents may be administered if you develop a headache.

When you have completed the recovery period, you will be taken to your hospital room or discharged to your home.

Once you are at home, notify your doctor of any abnormalities, such as numbness and tingling of the legs, blood or other drainage from the injection site, pain at or near the injection site, inability to urinate, fever, stiff neck, or headaches. If the headaches persist for more than 24 hours after the procedure, or when you change positions, you should contact your doctor.

You may be instructed to limit your activity for 24 hours following the procedure. Generally, if no complications occur, you may return to your normal diet and activities.

Your doctor may give you additional or alternative instructions after the procedure, depending on your particular situation.


Myelograms use dye and x-rays to create an image of the spaces in between your spine.

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X-Ray & Fluoroscopy

X-Ray & Fluoroscopy A machine send x-ray particles through the body, creating a picture that is captured on a special type of film.

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Computerized Tomography (CT Scan)

Computerized tomography scans are used in order to get a quick and detailed picture of the brain, chest, spine or stomach.

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Magnetic resonance imaging uses magnets and radio waves to take pictures inside the body.

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Virtual Colonoscopy for Cancer Screening

Virtual Colonoscopy for Cancer Screening

Virtual colonoscopy is a procedure that is done to look for small polyps or other growths inside your colon. Polyps that grow on the inside lining of the colon sometimes turn into colon cancers. The American Cancer Society recommends that men and women begin screening for colon cancer at age 50. If you have a family history of colon cancer or are at high risk for other reasons, your health care provider may want you to begin screening even earlier. Virtual colonoscopy every five years is one of several screening options.

Procedure overview

Virtual colonoscopy is done by taking hundreds of cross-sectional X-rays of the colon using a powerful type of computer. The computer can put all the images together to form the whole picture. These images can then be viewed by X-ray specialists and your doctors. This type of imaging is called computed tomography (CT), and the machine that makes them is called a CT scanner. The images can also be copied, transferred, and printed.

Reasons for the procedure

Colon cancer is the third most common cancer in men and women. The reason for virtual colonoscopy is to find colon cancer at an early stage when it can be treated most successfully. Colon polyps that are found by virtual colonoscopy can be removed (using conventional colonoscopy) before they turn into cancer.

An older and still common type of colonoscopy, called conventional colonoscopy, is also done to screen for colon cancer. This procedure is done by placing a long, flexible, lighted scope and tiny camera into the colon so that the doctor can look at the colon directly and remove any polyps that are present.

Virtual colonoscopy has several advantages over conventional colonoscopy:

  • Virtual colonoscopy is less uncomfortable and invasive than conventional colonoscopy and usually does not require any pain medication or anesthesia.

  • Virtual colonoscopy takes less time and poses less risk of puncturing the large intestine.

  • Virtual colonoscopy may be used in people who have problems such as swelling, bleeding, or breathing difficulties and who may not be able to tolerate conventional colonoscopy.

  • Virtual colonoscopy may be able to show areas of the large intestine that conventional colonoscopy can't reach.

Risks of the procedure

Virtual colonoscopy is a safe procedure, but it's not without risk. Conventional colonoscopy, however, also has some drawbacks. Among the risks and disadvantages of virtual colonoscopy:

  • During virtual colonoscopy, a small, short tube is placed into your anus so that air can be pumped into your colon. This inflates your colon so that polyps or other growths are more easily seen. Pumping air into the colon carries a very small risk that it may cause a rupture. But the risk is thought to be much less than with conventional colonoscopy.

  • Because polyps or suspicious growths cannot be removed or biopsied during virtual colonoscopy, you may still need to have a conventional colonoscopy if polyps or other suspicious areas are detected.

  • Virtual colonoscopy can miss some polyps that may turn into cancer if they are smaller than 10 mm. (Some of these might be detectable by conventional colonoscopy.) 

  • Unlike most other screening tests, virtual colonoscopy uses X-rays to create pictures of the colon and rectum. Radiation received during virtual colonoscopy is small, but it could be dangerous for pregnant women. If you are or could be pregnant, you should discuss this risk with your health care provider before the procedure.

  • Virtual colonoscopy is still fairly new, and it may not always be covered by medical insurance.

There may be other risks, depending on your specific medical condition. Be sure to discuss any concerns with your health care provider before the procedure.

Before the procedure

Before having a virtual (or a conventional) colonoscopy, you will need to have a bowel prep. A bowel prep is a way of emptying everything solid from your colon so that the CT images will be clear. Here is what is often involved with a bowel prep:

  • Your health care provider may ask you to limit your diet to clear liquids such as water, Gatorade, or clear broth for a day or two before the procedure.

  • The day before the procedure, you will be given a strong laxative in pill form or powder dissolved in liquid to help you empty your colon. You will likely have several loose or liquid bowel movements in the following hours. 

  • Just before the procedure you may be given a type of liquid to drink called contrast media that helps the inside of your colon appear brighter for the X-rays.

Always tell your health care provider about any medications you are taking and if you've had any reactions to contrast media for other X-rays in the past.

During the procedure

Virtual colonoscopy can be done wherever a CT scanner is available. In most cases you will go to the radiology department of a hospital or medical center. The actual procedure takes only about 10 to 15 minutes. This is what usually happens during a virtual colonoscopy:

  • The thin tube will be placed into your rectum to inflate your colon with air. You may feel a slight fullness.

  • A radiologist will position you face up on a table that slides into the CT scanner.

  • The radiologist will leave the room and the CT scanner will be operated from a separate control room. You will be able to hear and talk with the staff.

  • The table will move into and through the scanner. You may hear some whirring and clicking noises.

  • You may be asked to hold your breath at times.

  • The scan may need to be repeated while you lie face down.

After the procedure

In most cases you should be able to return home without assistance and resume your normal diet and activities. Medications and special instructions are usually not needed, but always check with your health care provider and the radiology staff if you have any questions. 

Virtual Colonoscopy

Less invasive than a traditional colonoscopy, VCs combine software with MRIs or CT Scans.

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