How is an MRI performed?
Your MRI in Paris
Have an MRI in Paris
What is an MRI scan?
MRI, or Magnetic Resonance Imaging, is a technique that enables radiologists to see into the human body in great detail without using X-rays. MRI images are obtained using a powerful magnetic field, radio waves and a complex computer system. The technique is safe and painless.
The examination process
When you arrive, you will be asked a number of questions, just as you were when you booked your appointment.
questions; the most important thing is to point out that you don't have a pacemaker, a heart valve or anything containing iron near your eyes or in your head.
To ensure good-quality images, you'll be told which garments to remove.
MRI acts like a giant magnet on objects containing certain metals.
You won't keep any buttons, staples, hair clips or metal zippers.
Leave jewelry, watches, keys, wallets, magnetic-stripe cards (credit cards, travel cards, etc.) and cell phones in a locker in the checkroom.
You will enter a room that will be closed during the examination. You'll lie on a bed that moves through a kind of tunnel for most machines, usually on your back and alone in the examination room; we'll communicate with you via a microphone. In all cases, the team is right next to you, behind glass. They can see and hear you throughout the examination.
If you want to call us, you can use a bell that we place in your hand.
If necessary, we can intervene or interrupt the examination at any time.
You will spend an average of 10 to 20 minutes in the examination room.
Your cooperation is important: you should try to remain perfectly still; in some cases, we'll use the microphone to tell you when to stop breathing for a few seconds.
At that precise moment, you'll hear a repetitive noise, like that of a boat engine or a tom-tom, during what is known as a sequence. An examination contains 3 to 6 sequences, or more if necessary.
Some tests require an intravenous injection, usually at the elbow.
Is MRI dangerous to health?
How will you feel?
The examination is not painful, but it is often a little long and the noise can be unpleasant.
A feeling of discomfort due to fear of being locked in (claustrophobia) is a common problem that
we know well. It can often be reduced by simple means, without any treatment.
If, for example, you feel uncomfortable in an elevator, tell the reception staff right away so that they can take special care of you.
Why does an MRI take so long?
An MRI scan consists of several sequences (4 to 5 in general), each lasting 3-4 minutes on average, to ensure good image quality; this enables organs to be viewed in several spatial planes (axial, sagittal, frontal, etc.), with different tissue contrasts (T1- or T2-weighted images). Some sequences are repeated after contrast medium injection. Image acquisition therefore takes an average of 20 minutes, to which must be added the patient's welcome, explanations to the patient, undressing, time to install the machine, time to inject the product, uninstalling the patient, and pauses between sequences. If the patient moves during a sequence, it will have to be repeated, which will lengthen the examination.
How long does an MRI examination take?
The average MRI scan lasts between 15 and 20 minutes. Some may be shorter, others longer.
What does an MRI scan look like?
Results
Just before the exam
An injection for an MRI: how and what are the risks?
The most commonly used contrast medium is Gadolinium.
This product is generally well tolerated. Trivial allergic reactions (urticaria) are possible.
Very serious allergic reactions are quite exceptional.
The sting may cause a small hematoma, which is not serious and will spontaneously heal within a few days.
During injection, pressure may cause the product to leak under the skin, into the vein.
This complication is rare (one case in several hundred injections, generally without serious consequences), and may exceptionally require local treatment.
Why is an MRI scan expensive?
The device itself requires a large investment for its acquisition and installation (electromagnetic shielding), and incurs very high annual maintenance costs. The lifetime of a device is around 7 years. Highly qualified personnel are required, as well as frequent updating of the entire computer system and software. An MRI technician performs your examination, and therefore spends between twenty minutes and half an hour per patient. Finally, image interpretation requires in-depth, specialized training on the part of the radiologist, as the technique is quite complex. The high cost of MRI is offset by the very high performance of this technique, enabling you to avoid other more complex or painful examinations to reach a diagnosis.
What is it all about?
MRI stands for Magnetic Resonance Imaging.
The word magnetic indicates that the device features a large magnet; the word resonance indicates that we're going to use radiofrequency waves, like those used by cell phones, to vibrate the many hydrogen nuclei making up your body's tissues, and thus produce images.
Noise during sequences
Noise is caused by the rapidly alternating current flowing through the coils that create the radio waves required for image acquisition.
I'm allergic
Please bring with you on the day of the exam
After your return home
In the vast majority of cases, you won't feel anything in particular. However, don't hesitate to let the team know if anything seems out of the ordinary.
It's normal to have questions about the exam you're about to take.
We hope we've answered your questions. Please do not hesitate to contact us again should you require any further information.
MRI and pacemakers?
Patients with pace-makers are not allowed inside the MRI chamber, as the magnetic field will disrupt the battery, causing heart rhythm disturbances that can be severe.
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