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MRI is one of the best diagnostic exams the detection and diagnosis of heart disease, acute stroke, vascular disease and many forms of cancer. Additionally, MRI is a vital part of diagnosing and treating sports injuries and is finding an increasing role in diagnostic mammography.
Each MRI examination is typically comprised of a series of 2 to 6 sequences, with each sequence lasting between 2 and 15 minutes. An "MRI sequence" is an acquisition of data that yields a specific image orientation and a specific type of image appearance or "contrast." Thus, a typical exam can last for a total of ten minutes to an hour, depending on the type of exam being run.
During the examination, a radio signal is turned on and off, and subsequently the energy which is absorbed by different atoms in the body is echoed or reflected back out of the body. These echoes are continuously measured by the MR scanner and a digital computer reconstructs these echoes into images of the body. The tapping heard during the MR exam is created when gradient coils are switched on and off to measure the MR signal reflecting back out of the patient's body. A benefit of MRI is that it can easily acquire direct views of the body in almost any orientation.
Frequently Asked Questions
Is the MRI scan painful?
The scan itself causes no pain. MRI uses no barium mixtures or dyes (iodine) as do some x-ray procedures, and has no known side effects. In some cases, your physician or the radiologist may order an injection of gadolinium to enhance the images.
Is there any preparation for the MRI scan?
Usually, there is no preparation. As a matter of fact, we recommend that you eat before your exam. One of our staff members will be calling the day before to confirm your appointment. If you have a pacemaker, metal implants or have worked in a job that exposes your eyes to metal shavings, you may not be able to have an MRI exam. You should also tell your technologist if you think you are pregnant. We do ask that women refrain from wearing eye makeup which may contain metallic substances, and remove underwire bras.
Is there anything else I will need to do for my scan?
Since the scanner is a very powerful magnet, you will be asked to remove all metal items at the time of your scan. The magnet will damage watches and can also erase any credit or bank cards. We encourage you to leave valuables at home. Please arrive at our imaging center a few minutes prior to your appointment, so our staff can explain your exam and answer any questions you may have.
How long will the scan take?
It will vary for each exam, since the average scan involves several "sequences" that last up to ten minutes each. Overall, each scan takes less than 45 minutes. For best results, you must lie still for the duration of your MRI exam. |
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