Thursday, August 14, 2008

MRI (magnetic resonance imaging)

I thought I'd show you a picture of what an 'open' MRI machine looks like. Some of the closed machines are a little more scary than this and some people feel a little claustrophobic during the process. What they will do is place your head in what looks like a cage and put a strap on your forehead so that you keep perfectly still.

The scan will take between 30-40 minutes. MRI uses magnetism instead of x-rays to build a detailed picture of your head. It is in no way painful and the only discomfort is in the fact that you will be asked to lie very still for this period of time. They will play you some music and I'm sure if you take your own favourites in they will play them for you so it's best just to relax. Once the process starts you will hear a series of what to me sounded like clicks and knocks.

You will be alone in the MRI room but the technician will be able to see and hear you and therefore if you need to attract their attention you only have to speak and a two-way intercom will pick you up.

I was given an injection of dye into a vein in my hand by way of intravenous needle, to produce a better evaluation of the images. This is like any other injection really and causes very little discomfort. The contrast is called gadolinium and does not contain iodine and is therefore less likely to cause allergic reactions.

Leave all your jewellery at home because these will have to be removed as they can interfere with the magnetic field of the MRI unit. You will usually be down to underwear and gown so will not have items such as zippers but be aware of items such as hair pins, hearing aids and removable dental work.

It is important that you remain perfectly still while the images are being recorded, which is typically only a few seconds to a few minutes at a time. You will know when images are being recorded because you will hear tapping or knocking sounds when the coils that create the magnetic field are turned on. You will be able to relax between imaging sequences.

The benefits of this technique is that it is noninvasive and does not involve any exposure to radiation. Where brain tumours are concerned the MR images are the most sensitive examination method as they are usually clearer and more detailed.

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