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The Difference between a CT scan and MRI

written by: DaniellaNicole•edited by: DaniellaNicole•updated: 3/3/2010

The difference between a CT scan and MRI is not understood by many. This is understandable because they share some similarities. Learn about the differences between an MRI and a CT scan in this overview.

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    CT/CAT Scan and MRI Technology Defined

    What is the difference between a CT scan and MRI? A CT or CAT scan is a Computed Tomography scan. The technology behind CT/CAT scans combines x-rays with computer technology in medical applications. An MRI is a Magnetic Resonance Imaging test. MRIs use the technology of magnetic fields and radio waves in order to perform various medical tests.

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    CT/Cat Scan and MRI Similarities

    To understand the difference between a CT scan and MRI, it can be helpful to first understand the similarities. In some cases, either test can be used to locate or diagnose a medical problem. Both involve a patient laying on a table that is inserted into a machine and both result in showing ‘slices’ of the patient’s body. Though there are similarities between the two, there are difference that can dictate which is used or why one is preferred over the other for certain diagnostic situations

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    CT/CAT Scan and MRI Testing Uses

    CT/CAT scans are generally performed in order to help locate or diagnose tumors, cancer, infection and blood vessel condition. MRIs are generally performed in order to examine, in a non-invasive 3-D way, tissues, organs and the skeletal system. MRIs may be used to help locate or diagnose tumors, aneurysms, stroke, multiple sclerosis (MS) and spinal cord injuries.

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    CT/CAT Scan and MRI Contrast Dyes

    Both CT Scans and MRIs may be performed without contrast dye. The MRI contrast dye gadolinium is considered to be safer than the CT contrast dyes that may be used. One such CT dye is barium sulfate and another is Gastrografin. It is important to note that barium sulfate is radioactive and x-rays use ionization radiation. No radioactive materials or contrast dyes are involved in MRI testing.

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    CT/CAT Scans vs MRIs

    CT/Cat scans were developed first and can be cheaper and easier to conduct than MRIs. This is why, despite the lack of radiation involved in MRIs, CT/CAT scans are still so widely used in medical diagnosis.

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    MRI – Definition. Mayo Clinic Staff. Mayo Clinic.

    Computed Tomography (CT or CAT) Scan. University of Virginia Health System – Radiology.

    Computed Tomography (CAT or CT) Scan. Johns Hopkins Medicine – Neuroradiology Division.

    Diagnostic Tests: Computed Tomography (CT Scan). Oncology Channel.

    Information About Intravenous and Oral Contrast Used in CT. Imaginis Corporation.

    What is an MRI with contrast (dye)? RemakeHealth. January 11, 2009.

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