FAQs

An MRI is a machine that uses a large magnet, radio waves, and a powerful computer to produce cross-sectional images of the body. No X-rays or other ionizing radiation is employed. MRI is the shortened form of magnetic resonance imaging.

To understand how an MRI works, let’s start by focusing on the “magnetic” in an MRI. The major and most important component in an MRI system is the magnet. The magnet in an MRI system is rated using a unit of measure known as a tesla. MRI provides a magnificent view inside the human body.

A large magnet surrounding the body causes the hydrogen nuclei (protons) in water molecules to align in a particular direction, and then radio waves strike the protons, causing them to spin out of alignment. When the radio signal is turned off, the protons return to their previous alignment, giving off new radio waves at the same time. The returning radio signals are received and analyzed by a computer, which then creates cross-sectional images of the body.

Like CT, MRI can be used to image almost any part of the body, although MRI produces pictures containing information that may not be seen on a CT scan. For some things, MRI is more useful than CT, and for some things CT is more useful. Sometimes, both are necessary, since the information gained from one may complement or clarify information gained from the other. MRI is often used for the following:

• Brain and nervous system: MRI is the most accurate tool for evaluating most diseases of the brain and spinal cord, including strokes, tumors, and multiple sclerosis.
• Musculoskeletal system: MRI is the most accurate way to non-invasively image most joints (knees, shoulders, wrists, etc) for problems involving cartilage, ligaments, tendons and muscles.
• Breast: with our new EXCITE technology upgrade come H.D. VIBRANT (Volume Imaging for Breast Assessment). We can now simultaneously examine both breasts in high resolution in a single patient visit.
• Other: MRI can also be useful for evaluating the neck, liver, kidneys, pelvic organs, blood vessels, and lymph nodes.

MRA is “magnetic resonance angiography”. Using special techniques, MRI can be employed to produce highly detailed images of many arteries and veins, without the need to insert catheters into the body or inject iodinated contrast agents. The pictures obtained look much like a conventional angiogram, but are obtained non-invasively.

You will be asked to lie on your back on a comfortable scanning table. Some examinations require an intravenous injection of a small amount of Gadolinium – a substance that improves the visualization of some structures and is necessary to demonstrate some diseases or conditions (especially for some brain and abdominal exams, and for MRA). This substance almost never causes side effects, and is quickly excreted by the kidneys. A “surface coil” may be placed on or around the part of your body to be imaged, such as the head, knee or shoulder. Since the large magnet and rapidly changing magnetic field produces a loud noise at times during the exam, you will also be offered ear plugs. Most exams take anywhere from 15 to 45 minutes to complete.

Prior to your going in to the exam room, a staff member will interview you and will explain what will happen during your test. A technologist will stay in constant contact with you throughout the exam.

For a list of forms you can fill out prior to this procedure, please visit the Patients page where you’ll be able to print off the PDF forms you’ll need.

Not everyone can be safely exposed to a magnetic field, so if any of the following apply to you, you should let us know before making an appointment:

• cardiac pacemaker
• history or possibility of a metal fragment in your eye, even if it has been removed
• aneurysm clip in the brain
• ear or eye implant
• nerve stimulator
• drug infusapump
• recent surgery (less than 8 weeks ago)
• any other procedure where medical personnel might have left a stent, coil, filter, wire, or any other implantable device inside your body

In most cases, reports are provided within 24 hours.

CT stands for “computed tomography,” taken from the Greek word “tomos” meaning “to cut” or “to slice.” CT uses ordinary X-rays coupled with special detectors and a powerful computer, to create images, which appear as sections or slices of the body.

CT scanners can be used to evaluate almost any part of the body for a variety of different problems. Some examples are:

• Head & Neck: CT can be used to evaluate the brain for strokes, headaches, or injury. It can also be used to evaluate the sinuses, facial bones and structures of the neck.
• Chest: CT is excellent for evaluating the lungs for infection, emphysema, tumors and other conditions.
• Abdomen & Pelvis: CT is extremely useful for visualizing all organs of the abdomen and pelvis, and is often performed to evaluate the possibility of appendicitis, diverticulitis, kidney disease, liver or gallbladder disease, etc.
• Spine: CT is very helpful in evaluation of spinal fractures, and can also be used to evaluate disc herniations and other causes of neck and back pain.
• Blood vessels: A type of CT scan can be performed for visualization of arteries or veins; it is called CT Angiography (CTA). The latest multidetector CT scanners produce the most accurate CTA examinations.

With the latest multidetector CT scanners, most examinations take less than 10–15 minutes. You will be asked to lie on a comfortable table, which will slide into the opening of the machine, and you will move through the opening as your body is being scanned. If intravenous contrast material is required for your exam, a temporary IV will be started in your arm by a technologist. For abdominal scans you will also be asked to drink a dilute barium solution, beginning approximately two hours before the procedure.

For a list of forms you can fill out prior to this procedure, please visit the Patients page where you’ll be able to print off the PDF forms you’ll need.

The earliest CT scanners required as long as two minutes to produce a single, very blurry section of the body. The very newest ones can produce multiple, highly detailed sections in less than one second. Early CT scanners were able to “slice” the body in only one direction, while newer ones, called “helical” CT scanners, can “slice” the body in many different ways, and can even produce three-dimensional images. In CT technology, “multidetector” scanners can produce even more detailed 2-D and 3-D images than were ever before possible, and in much less time. The increased speed of these newer machines often allows for a significant reduction in the amount of intravenous contrast material required for an exam (see below for more about contrast material).

Intravenous contrast material is an organic compound containing Iodine, which greatly improves the visualization of blood vessels and many organs on a CT scan. IV contrast material is not usually required for spinal exams, but is often necessary for proper evaluation of the head, chest, abdomen and pelvis. (If you are diabetic and taking Glucophage (metformin), Glucovance, Riomet, Metaglip or Advandamet and have been scheduled for a CT scan, please phone for special; instructions.) Orally administered contrast material (a dilute barium solution) is usually necessary for CT scans of the abdomen and pelvis, where it aids in visualization of the gastrointestinal tract.

If your examination requires intravenous contrast material, you will be asked to drink 4–6 cups of clear liquid (fruit juice, soda, coffee, water) beginning 4 hours before your exam. You may take regular medications, but eat no solid food during that time. For examinations of the abdomen and pelvis, you will also need to drink a dilute barium solution (oral contrast material) beginning 3 hours prior to your exam. (You can stop by our office anytime before your appointment, to pick up this solution.)

CT scanning uses X-rays, and the amount of radiation exposure is similar to that of many ordinary X-ray examinations. The risk from this amount of radiation is minimal for most people, but can be more for a fetus. CT scanning is therefore not usually performed on pregnant women, unless absolutely necessary. Intravenous contrast material can cause allergic reactions in some people. These reactions are usually minor (such as a temporary skin rash or hives) and require little or no treatment; more serious reactions are very rare.

In most cases, reports are provided within 24 hours.