North Fork Radiology - MRI Scanning

What is an MRI Scan?

An MRI or magnetic resonance imaging is a medical diagnostic technique that creates images of the body using the principles of magnetic resonance. An MRI can generate thin-section images of any part of the body including the heart, arteries and veins—from any angle and direction, without surgical invasion. MRI is preferred for diagnosing most diseases of the brain and central nervous system. MRI creates “maps” of biochemical compounds within any cross section of the human body. These maps give basic biomedical and anatomical information that provides new knowledge and may allow early diagnosis of many diseases. MRI is possible in the body because the body contains protons, the nucleus of the hydrogen atom. The principles of MRI take advantage of the random distribution of protons, which possess fundamental magnetic properties. Since MRI uses magnetic and radio waves there is no exposure to radiation.

How is an MRI Scan Performed?

The patient lies inside a large cylinder-shaped magnet. The diagnostic process follows three steps. First, the MRI creates a steady state within the body placing the body in a steady magnetic field that is 30,000 times stronger than the earth’s magnetic field. Then the MRI stimulates the body with radio waves to change the steady-state orientation of the protons. It then stops the radio waves and “listens” to the body’s electromagnetic transmissions at a selected frequency. The transmitted signal is used to construct internal images of the body.

Some examinations require the patient to receive an injection of “contrast material” to facilitate visualization.

During the examination you must remain completely still. MRI scans take approximately 45-90 minutes, dependent on the actual exam type.

How to Prepare for an MRI Scan

There aren’t any prior examination requirements. However, if other imaging modalities were performed at another facility relevant to your scheduled examination it is necessary to bring those films with you.

Who Can’t Have an MRI and Why?

It is important to note that patients with cardiac pacemakers, patients who might have an iron filings next to their eyes (for example, sheet metal workers), patients with inner ear transplants and patients with aneurysm clips in their brains are not candidates for MRI as such an examination can be hazardous to their health and well-being and can in fact result in death.

PLEASE BRING YOUR CT/MRI Films with you if they weren’t performed at North Fork Radiology.

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