Sierra Imaging faq-mri


What is an MRI?

A diagnostic radiological modality, using magnetic resonance technology, in which the magnetic nuclei (especially protons) of a patient are aligned in a strong, uniform magnetic field, absorb energy from tuned radiofrequency pulses, and emit radiofrequency signals as their excitation decays. These signals, which vary in intensity according to nuclear abundance and molecular chemical environment, are converted into sets of tomographic (selected planes) images by using field gradients in the magnetic field, which permits 3-dimensional localization of the point sources of the signals.


What is the difference between MRI and CT intravenous (IV) contrast?

MRI IV contrast is a gadolinium based solution which will show blood vessels/blood flow. CT IV contrast is an iodine based solution that will show areas of blood vessels/blood flow.

I have metal in my body from surgery. Can I have a MRI?

It depends upon what type of surgery and what type of metal. Please notify a SIA staff member if you have had this type of surgery.

What about dental work?

You can have a MRI with fillings and dental bridgework

Is MRI safe?

Yes – provided you do not possess certain implants, do not have any metallic foreign objects in your eyes, or other have had surgical procedures which may be contraindicated.

Do I have to lay still for my MRI?


What is the difference between MRI and CT?

MRI uses a combination of a strong magnetic field, radiofrequency, and computer technology. CT uses a combination of x-rays and computer technology.

Why would I have a MRI as opposed to a CT?

Because the indication, your medical condition, and the area of interest can be better imaged and diagnosed in MRI.

Why are MRIs so noisy?

Large amounts of electric current flows through many switches to produce a powerful electromagnet (gradient coils). The rapid switches of the magnet cause a loud popping noise and vibrations. This manipulation of the electromagnet allows us to control slice thickness and direction and to produce 3D images.

Do I need a referral from my physician to have a MRI?


What should I wear?

For your convenience, you should wear loose-fitting clothes. You may be asked to change into one of our hospital gowns. You will also need to remove any jewelry or other metal objects you are wearing. Our patient dressing areas have facilities to store any personal items.

Is the open scanner better than the traditional/conventional bore scanner?

While open scanners, in general, are a newer design, they aren’t necessarily better or worse technology. The design of the open scanner creates a smaller magnetic field which requires the scans to be longer. The design of the bore scanner creates a stronger magnetic field which reduces scan times. The choice to use an open scanner over a bore scanner is usually based upon two factors: claustrophobia and the size of the patient. Because the open scanner’s design is less confining than the bore scanner, patients who are claustrophobic and/or large tend to be more comfortable in the open scanner.

I’ve been told that the traditional/conventional bore scanner is closed on both ends, dark inside and that I’m left alone for 45 minutes – is this true?

The bore scanner is approximately 6 feet long and 3 feet in diameter. There are no doors on either end, it has a light, fan, and intercom system. The technologist will speak to you via the intercom system and will be operating the scan just a few feet away while visualizing you through a window. The scanner does not run itself, therefore the technologist is always present.