UPSC General Studies Sample Paper General Studies Sample Paper-9

  • question_answer
    What is the difference between CAT Scan and Magnetic Resonance Imaging?
    1. CAT scan uses X-ray, MRI uses no X-ray and thus, no ionising radiation.
    2. CAT scan gives best results for soft tissues while MRI gives best results for bones.
    Select the correct answer using the codes given below.

    A)  Only 1             

    B)  Only 2

    C)  Both 1 and 2                

    D)  Neither1nor 2

    Correct Answer: A

    Solution :

    [a] The Statement 2 is not correct. MRI does not do a very good job with bones. Further, MRI is also not advised to the people, who have an artificial pacemaker implanted as the magnetic/radiowaves may interfere. Some more details are Magnetic Resonance Imaging (MRI) Magnetic Resonance Imaging (MRI) or Nuclear Magnetic Resonance Imaging (NMRI) is primarily a medical imaging technique most commonly used in radiology to visualise the internal structure and function of the body. MRI provides much greater contrast between the different soft tissues of the body than Computed Tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular and oncological (cancer) imaging. Unlike CT, it uses no ionising radiation, but uses a powerful magnetic field to align the nuclear magnetisation of (usually) hydrogen atoms in water in the body. Radio frequency fields are used to systematically alter the alignment of this magnetisation, causing the hydrogen nuclei to produce a rotating magnetic field detectable by the scanner. This signal can be manipulated by additional magnetic fields to build up enough information to construct an image of the body CT: Compiled Tomography. Computed Tomography (CT) It is a medical imaging method employing tomography. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. The word tomography is derived from the Greek word 'tamos' (slice) and 'graphein' (to write). Computed Tomography was originally known as the EMI scan as it was developed at a research branch of EMI, a company best known today for its music and recording business. It was later known as Computed Axial Tomography (CAT or CT Scan) and body section Steganography.


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