Magnetic Resonance Imaging - العلم نور


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الجمعة، 29 مارس 2019

Magnetic Resonance Imaging

Magnetic Resonance Imaging

         Magnetic Resonance Imaging (MRI) is a medical scan which is used to generate detailed images of the inside body organs. For this process to be done, MRI scan uses a strong magnetic field and radio waves. Radio frequencies which are used for this purpose can be emitted by certain atomic nuclei which are placed in magnetic field.
         MRI is developed in 1970 s. since that time, it's used as an important imaging technique. It's used in approximately all hospitals and clinics for the purpose of medical diagnosis.  
Construction of MRI scanner
         The MRI scanner has many major components which are necessary to construct the scanner. These major components can be as follows:
§  The main magnet. It's used to polarize the sample.
§  The shim coils. They are used to correct the shifts which happen in the homogeneity of the magnetic field.
§  The gradient system. It's necessary for localizing the MR signal.
§  RF system. It's important for the excitement of the sample and detection of the resulting MR signal.
         A strong magnetic field is required for MRI which will be generated by a magnet of strength between 0.2 to 7 T "teslas". Liquid helium is required for the superconducting magnets which are mostly used in clinics.
Magnetic Resonance Imaging Uses
Medical Use
·       MRI is used to investigate neurological cancers. It is necessary for many conditions which occur in the central nervous system such as epilepsy, dementia and Alzheimer's disease. It's also used in N-localizer device to treat intracranial tumors and other treatable conditions within radiosurgery.
·       There is a specific type of MRI used for the detection of bile ducts, liver and pancreas called Hepatobiliary MR. It's important to use contrast agents in liver MRI to give the chance of performing functional biliary imaging.
·       MRI scan is used for the examination of any part of the body such as brain, breasts, bones, spinal cord, heart and other internal organs of the body to help diagnose conditions.
·       It's also can be used to examine blood vessels in order to plan treatments and searching about the most effective treatment for the patient disease.
Non-Medical Use
·       MRI is used widely in the industry for the analysis of many chemicals.
·       The ratio of water and fat in foods can be measured by the use of nuclear MR technique.
·       Magnetic resonance imaging can be also used for monitoring of corrosive fluid flow in pipelines.
·       Catalysts and other molecular structures can be studied by the use of nuclear MR.
During MRI Scan
-        Sometimes it's required to get a contrast dye before MRI scan. This dye is used to enable doctors to see your inside body structure clearly. Gadolinium dye is often used in MRI scan.
-        The part of your body which is required to be examined will be inside the machine during the test.
-        A strong magnetic field is created by the machine inside your body. That enables the MRI to send signals to the computer which use them to make some pictures of the body parts.
-        This will take between 20 to 90 minutes to finish the scan.
Persons Shouldn't get MRI Scan?
ý During the first trimester of pregnancy, pregnant women shouldn't get the MRI scan as the dye may damage the baby organs.
ý If you have kidney disease, you can't get the contrast dye which is required for the MRI scan.
ý  Don't get the MRI scan if you have any type of metal inside your body such as brain clips and certain metal coils.

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