MRI stands for magnetic resonance imaging. MRI, is a way of obtaining very detailed images of organs and tissues throughout the body without the need for x-rays. Instead, it uses a powerful magnetic field, radio waves, a rapidly changing magnetic field, and a computer to demonstrate whether or not there is an injury or some disease process present. The MRI aligns atomic particles called protons that are present in most of the body's tissues. Radio waves then cause these particles to produce signals that are picked up by a receiver within the scanner. The signals are specially characterized using the changing magnetic field, and computer-processed to create very sharp images of tissues as "slices" that can be viewed in any plane or from any direction. MRI is widely used for evaluating orthopedic, joint, and sports medicine related injuries, as well as disc disease and other conditions that affect the spine. Neurologic imaging and tumor evaluation are other uses of MRI.  

MRA stands for magnetic resonance angiography. It is an MRI examination devoted to evaluation of the vascular system, whether it be arteries or veins. MRA examinations are typically of the vessels of the brain, the carotid arteries (the main arteries in the neck), the aorta, the renal arteries (the arteries feeding the kidneys) or vessels of the legs. The main reason for performing an MRA examination is to look for stenosis, or narrowing, of specific vessels.

Frequently Asked MRI / MRA Questions

What MRI/MRA services are provided by Advanced Imaging of San Marcos?
 
These include, but are not limited to MRI evaluation of the brain and spine, joints, abdominal organs, bile ducts, and arteries.

Do I need a doctor’s prescription for an MRI?

Yes. Be sure to bring it with you when you come in for your MRI if your doctor hasn’t already faxed it to our office. 

Is the MRI covered under my insurance?

Usually yes. Our staff will contact your insurance company to verify your coverage and will let you know should a problem arise. We will also let you know how much you will owe at the time of the exam and how your insurance company will cover. Additionally,  please let us know if you have any supplementary insurance.

What if I need to cancel my appointment?

As a courtesy, please notify Advanced Imaging of San Marcos as soon as you are aware you will need to cancel your exam. If you need to reschedule for another time we will be happy to accommodate you with another appointment time.

Is there radiation associated with an MRI? 

Unlike most other radiology imaging procedures, there is no radiation associated with an MRI exam.

Can anybody have an MRI scan? 

No. For some people, an MRI can be dangerous, even fatal. If you have a cardiac pacemaker, you should not have an MRI. It can be fatal. There may be certain parts in the pacemaker that may be adversely affected by the magnetic field of the MRI scanner, causing the apparatus to malfunction or cease operation. 
Other Potential Dangers:

Metal Implants

Drug infusion Devise/Pump

Ear Implants

Inferior Vena Cava filter

Metal objects in Eyes

Certain Penile Implants

Pregnancy

Vascular Coils and Filters

Brain Aneurysm clips

Heart Valves

Neurostimulators

If any of the above applies to you, it MAY BE DANGEROUS for you to have an MRI exam. Be sure to make the technologist and the radiologist aware. They will be able to tell you if it is safe for you the MRI exam. In most cases you will be able to have the scan, but please leave that decision to the professionals.

What is the difference between MRI and CT?

Both MRI and CT are diagnostic exams used to thoroughly image a selected area of the human body. Similarly, both MRI and CT require the use of a large machine, and each method relies upon computer technology to reconstruct a cross-sectional image of the body. Aside from these very fundamental similarities, there are many inherent differences between MRI and CT scans.

Magnetic Resonance Imaging (MRI) - Developed in the mid 1980’s, MRI technology utilizes radio frequency waves and very powerful magnets. After applying a very strong, localized electromagnetic field, the MRI scanner emits a series of radio pulses into the body, exciting the hydrogen protons found in the body’s soft tissue. Upon measuring the relaxation times of these hydrogen protons, the MRI scanner employs sophisticated computer technology to interpret the protons’ behavior and recreates a 3-dimensional image of the body. Since hydrogen is the most abundant element in the body, MRI technology is capable of producing amazingly clear images of organs and soft tissue. MRI is able to detect disease or injury in muscle structure along ligaments, and is used to assist in the visualization of tumors. The ability to visualize soft-tissue and the vascular system make MRI an outstanding tool for imaging brain and spinal cord abnormalities. MRI is non-invasive, although certain studies may require the use of an intravenous contrast agent. MRI does not involve any ionizing radiation, and aside from a persistent thumping noise, patients will experience no discomfort or side effects.

Computerized Tomography (CT or CAT scan) - Developed in the 1970’s CT technology utilizes a highly sensitive X-ray beam that is focused on a specific part of the body. Upon passing through the body, the beam hits a detector, which relays this information into a computer. The computer analyzes the information based upon tissue density, and feeds it into a cathode ray tube. Like MRI, a cross-sectional representation (like "slices" of bread) of the body is produced. Bone shows up white, gases and liquids black, and tissue as varying shades of gray, depending on density. Generally, CT provides much better visualization of bone detail than MRI. CT scans provide excellent information on anatomical features and tissue density (this allows for the detection of tumors, and sometimes the ability to distinguish between malignant and benign tumors). CT scans can also detect calcium deposits, cysts, and abscesses. They are often used in place of ultrasound for obese patients because fat deposits often hinder ultrasonic waves.

How long does an MRI exam take? 

The length of the MRI exam varies depending on the study being performed. Most MRI exams are on the order of 30 minutes, with some being slightly shorter or longer. All of our exams are tailored to your specific history. At Advanced Imaging of San Marcos, we pride ourselves on doing the most detailed examination possible. No corners are cut. Therefore, many examinations may appear longer than a similar study at other imaging center.  

Do I have to lie very still during the exam?

Yes, as still as you can. It is important to minimize movement in order to achieve the best imaging results. If the scan has too much motion, the exam will not be diagnostic. The technologist will give you opportunities to move occasionally throughout the scan. 

Is it safe to have an MRI if I’m pregnant?

If you are pregnant or think you might be pregnant, you must first consult with the physician before you have an MRI scan. You must also inform the staff at Advanced Imaging of San Marcos.
It has not been shown that MRI is harmful to unborn children. However, if you choose to have the MRI, you will be asked to sign a consent form.

Do I need contrast/dye when I receive my MRI? 

Depending on the exam ordered by you physician and the questions your doctor has, your may be required to have contrast/dye administered by vein. This would be performed by the MRI Technologist or Radiologist.  

Can I be allergic to the contrast/dye?

The contrast material used for an MRI is not the same as that used for a CT examination or diagnostic x-ray studies. You should not experience any symptoms from the contrast. It is extremely rare to have any type of allergic reaction to the contrast material (nearly one in a million). An allergy to CT contrast does not mean that you will be allergic to MRI contrast, and does not preclude you from having a contrast enhanced MRI examination. 

What will happen during my examination?

If your test requires you to disrobe, you will be escorted to a dressing room where you can change into a gown and remove jewelry or other objects that may interfere with the exam. For the exam, you will be asked to lie down on a movable table. You will be positioned on the table by the MRI technologists so that the area being imaged is in the middle of the bore. During the procedure, the table may move over short distances. The technologist will be talking with you through an intercom and may ask you to hold your breath or to keep still to prevent motion or blurring of the pictures. The MRI scanner does make noise. We provide earplugs or headphones for you to listen to music during the exam if you desire. 

What if I am claustrophobic? 

Most patients who are claustrophobic can still undergo a closed MRI exam. With the assistance of the MRI technologist, it is usually possible to complete the MRI study. Some patients may require mild sedation with oral medication or other medication prescribed by their physician to be taken prior to the exam. If you think you might need sedation, please inform the scheduler when the appointment is being made. You will need to arrive at least 30 minutes prior to your appointment time to be given the sedation. You will need someone to drive you home.

Can someone be in the scan room with me during my exam?

Yes, a family member or friend can join you in the scan room but only after they have been screened with all of the criteria on the MRI checklist.

What do I have to do to prepare myself for an MRI?

Preparing for an MRI is easy. Unless your doctor tells you otherwise, you may take your medications as usual. There are no food or drink restrictions.

Why is it so important to remove ALL metallic objects before I enter the MRI scanning room?

You will need to remove all metal objects for safety reasons and because they can cause artifacts to appear on the MRI image. All body piercings will need to be removed prior to the exam.

How do I obtain results of the MRI scan?

After you leave, your images are interpreted by a radiologist, a doctor who specializes in reading MRI. The written report is then faxed or called to your physician with the results of your study. Your physician will then contact you to discuss your results. Technologists are not qualified to interpret MRI exams, nor are they allowed to, so please don’t ask them for their opinions.

What if I need to cancel my appointment.

As a courtesy, please notify Advanced Imaging of San Marcos as soon as you are aware you will need to cancel your exam. If you need to reschedule for another time we will be happy to accommodate you with another appointment time.