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3T High field MR system

Very high field MRI

Frequent asked questions (FAQ)

Explanations hereafter are adapted to the high field MRI we use in our institute. Some of these comments cannot be applied to other MRI systems. If you are to be examined elsewhere, please ask for specific information.

  1. What should I do if I think I might be be pregnant?
  2. Is it necessary to be fasting for an MRI? How should I prepare?
  3. Should I expect MRI time to be delayed?
  4. My body harbours some metal elements
  5. Can you accept obese patients?
  6. I am allergic
  7. I suffer from a cold
  8. I am very claustrophobic and I think that I wouldn't even enter your MRI
  9. I cannot tolerate binds
  10. Will you let me alone inside?
  11. Why do you maintain the MRI door closed?
  12. I cannot stand loud noise
  13. Why are MRI sequences so noisy?
  14. Shall I feel something during my MRI examination?
  15. Could MRI induce changes in my body?
  16. Why is MRI imaging lasting so long?
  17. Why cannot I move during MRI sequences?
  18. May I read or do something else during MRI?
  19. Is your MRI able to perform every usual imaging?
  20. Is image quality higher than other systems?
  21. Is MRI able to diagnose any disease?
  22. Why are MRI images not colored?
  23. Why is MRI imaging fairly costly?
  24. I am not sure that my insurance will reimburse my MRI examination
  25. Do you perform MRIs without medical prescription?
  26. Will you tell me my result at the end of examination?
  27. Shall I get my MRI CD-ROM?
  28. I brought older X-rays along...
  29. I have lost my MRI films...
  30. I have a pacemaker: is it still possible to undergo MRI ?
  31. I have a cardiac valve: is it safe ?
  32. I have tattoos / piercings
  33. Do I really need an injection ?

What should I do if I think I might be be pregnant ?

Although MRI has been proven to be innocuous and does not generate any dangerous radiation, MRI imaging is not adviced during the first two trimesters of pregnancy. This rule may be simply ignored if a life-threatening disease has to be investigated.


Is it necessary to be fasting for an MRI? How should I prepare?

You do not have to be fasting for MRI, except for abdominal imaging. You may in any case take your daily drugs with a little water. Please do not make up, especially for head and neck examinations and remember that all jewels included piercings need to be removed before MRI imaging.


Should I expect MRI time to be delayed?

MRI imaging is a complex technique and schedules may sometimes be disturbed by unforeseen events. It may happen that you are asked to wait a little for your turn. That is why we advise you to schedule at least two full hours for your MRI to complete.


My body harbours some metal elements

If you are harbouring a pacemaker or another electronic implant (insulin pump, for example), any metal element in your head or close to your eyes, please contact us quickly to decide if your MRI should be cancelled. For any other metal object location, there is no danger; please just mention it to the technician in charge of your examination. Plastic implants should not interact at all with MRI.


Can you accept obese patients?

Our MRI, open on all sides, is specially fitted for obese patients, when they cannot always enter a closed MRI "tunnel". Upper weight limit is 135 Kilograms.


I am allergic

It is important to mention any allergy or drug intolerance, in case we have to administrate contrast agent. Gadolinium used in MRI is very rarely allergenic, even less than already safe modern iodinated contrast agents used for example in CT-scan imaging.


I suffer from a cold

As coughing may induce movement artefacts and alter image quality, we advise you to call us and delay your date.


I am very claustrophobic and I think that I won't be able to undergo an MRI

Most sensitive patients can still manage to undergo MRI with some help. Thanks to high field and tenchnology, it is possible to program very short sequences. Our patients are always handled with patience and understanding, nobody being forced into the magnet. In most difficult cases, we propose short-termed sedation with very good efficacy against anxiety. That is why we recommend anxious patients to ask someone to drive their car back, because in case they would receive sedation, no driving is allowed for a few hours.


I cannot tolerate binds

Patients are never attached during MRI. We only secure the part to be examined with cushions against unintentional movements. You would be able anytime to get out of MRI by yourself if you felt it necessary.


Will you let me alone inside?

If you come with someone else, he (she) may stay along with you during your examination. The technician will anyway watch at you all the time and is able to hear you and speak to you with a microphone. For further security, an alarm is placed in your hand to be pressed if necessary.


Why do you maintain the MRI door closed?

MRI uses receiver antennas which are very sensitive to the weak radio waves emitted back from your body during a sequence. Radio waves coming from outside must be filtered out by a continuous shielding, which would be interrupted by opening the door during the sequences, leading to image quality deterioration. Anyway, the door can always be openend from inside if necessary.


I cannot stand loud noise

MRI sequences are less noisy in this high field MRI. If noise is still a problem, just ask for extra ear protection.


Why are MRI sequences so noisy?

Noise is generated by very fast inversion of electric current in radio waves emitters used to obtain images. There are no moving parts inside an MRI device.


Shall I feel something during my MRI examination?

Most people do not feel any difference between being inside or outside MRI. Very rarely, highly sensitive persons mention slight sensations in their body, rarely unpleasant and never painful. In very high fields, some feelings may be a little more frequent, like dizziness, metallic taste in the mouth, heating. With very high gradient frequency, sensations may be related to low currents generated in nervous fibers. But these phenomena are safe anyway, thanks to severe security thresholds limits.


Could MRI induce changes in my body?

High magnetic field and electromagnetic waves (radio waves) induce multiple short-timed magnetic orientation changes of a small minority of your body atoms. Under normal examination conditions, no adverse effects have ever been proved, even in foetuses. We have now more than 20 years experience and tens of millions of MRIs are performed every year in the world, showing that this technique is safe. In addition, every MRI machine is severely controlled in a regular manner to ensure safety and stable image quality.


Why is MRI imaging time consuming?

An MRI is composed of sequences (usually 5-7) , each about 2-3 minutes of duration necessary to ensure image quality. Every sequence corresponds to one orientation in space (transverse, sagittal or coronal), each one with two possible tissue contrasts parameters (T1 or T2 weighting). Sometimes sequences must be repeated after contrast agent injection. Mean acquisition time is about 20 minutes, plus time for patient explanations and installation, eventual contrast injection, deinstallation and pauses between sequences. Furthermore, if the patient has moved during a sequence, this sequence needs to be repeated, prolonging examination time.


Why cannot I move during MRI sequences?

Most sequences need a few minutes to complete; during this time, MRI builds a very precise body map to obtain an image. Any patient movement during this period will produce blurred image with information loss. Image formation can be compared to a photography by night, for which a long exposition time is necessary to gain enough light to impress the film (where light is compared to the MRI signal). The shorter the sequence, the less signal is obtained and the less precise the image will be.


May I read or do something else during MRI?

It is theoretically possible. But practically, even head movements or page turning could provoque whole body movement and image spoiling. That's why we prefer that the patient takes advantage of this time to rest and relax; it is sometimes even possible to sleep.


Is your MRI able to perform every usual imaging?

More than this: any special technique is available, like MR angiography, breast MRI and multiparametric examinations.


Is image quality higher than other systems ?

Image quality at our 3T system is the highest available in the market. Many MRIs are still working at lower fields, like 1.5 or even lower. Our high field MRI allows very precise images and shorter examination time.


Is MRI able to diagnose any disease?

MRI is a very potent diagnostic tool for a wide medical application domain. However, there are diseases that do not appear on imaging, either because changes are too weak to be recorded, or because they simply do not induce enough body tissue changes. Lesion detection is also limited by size, as submillimetric abnormalities may be difficult or impossible to see.


Why are MRI images not colored?

The image computed from the different signal intensities measured in each point of the body (pixels) is coded in gray levels by the apparatus, whether it is for MRI, CT scan or ultrasound. As intensity is the sole variable, the computer cannot decide by himself which color he will attribute to different tissues: two tissues having the same intensity may be totally different, like liver and spleen for example; conversely, two structures showing different signals can belong to the same tissue, like a cyst in the liver. The job of the radiologist is to distinguish a tissue from another along with their anatomic location in the body, which a computer hardly could realise. For aesthetical purposes, a non medical journal may decide to add color to a radiological image placed on its front page; however, color neither does enhance details nor refine the diagnosis for the specialist. If, on the other hand, another variable is obtained, like isotope radioactivity in nuclear medicine (scintiscanning, PET-CT), or blood flow in the vessels, as for color Doppler, it is very beneficial to superimpose a color coding of this dynamic variable on the b/w images. This procedure can also be carried out in functional MRI, in which blood flow or regional activity of the brain can thus be better illustrated.


Why is MRI imaging fairly costly?

MRI costs are determined by the high price of the machine, of its installation (magnetic shields) and yearly maintenance. Life expectancy of an MRI installation varies from 5 to 10 years. Moreover, technician full time presence is required for each examination, which duration is about half an hour. Lastly, image interpretation need special medical training because of MRI complexity. MRI costs are largely compensated by its high diagnostic performance allowing to obviate many other painful or complex investigations.


I am not sure that my insurance will reimburse my MRI examination

If your MRI is medically justified, you should not worry: your insurance has to endorse diagnostic costs prescribed by your doctor. However, your insurance may ask your doctor to explain his diagnostic strategy. In very peculiar cases, it may be useful to ask your insurance before scheduling MRI.


Do you perform MRIs without medical prescription?

Insurance reimbursement will occur only for a medically prescribed MRI. If you choose to pay your MRI by yourself, you will have to indicate us to which referring physician we should send the medical report, so that you can get medical advice based on MRI results.


Will you tell me my result at the end of examination?

Patient is the first owner of his medical data and it is his right to have access to it. Anxious patient reassurement is often possible just after MRI achievement if the result is obvious. However, radiologists prefer to let the referring doctor inform his patient himself, because he knows him better and will be able to comment the results and propose a treatment. Radiologists often refrain from talking about treatment with their patients because they only have a partial view of one's problems and are not aware of all possible treatments in every medical speciality.


Shall I get my MRI CD-ROM ?

If you have a medical visit the same day, you may go along with your images for your consultation. Otherwise, we can send the images with the report directly to your doctor. Written results will be sent to your physician, usually in the next 24 hours.


I brought older X-rays along...

This was the right decision, because we need older exams (X-rays, ultrasound or CT-scan) relating to the same medical problem for comparison. After reporting on your MRI, we will send the whole file to your referring doctor, who will eventually return it to you on your next consultation. We don't archive any patient documents in our institute.


I have lost my former MRI

Your medical data are unique, they belong to you and it is up to you to carefully preserve your images against light and humidity for 10 years or more if required. For comparison sakes, most images can now be saved in a PACS (Picture Archive and Commmunication System) at the radiology institute.


I have a pacemaker: is it still possible to undergo MRI ?

MRI is fondamentally incompatible with any electronic implanted device, which could be damaged or could not function correctly and cause severe harm to the patient. However, some recent devices may be switched off or into a "MRI-compatible" mode. This can only be accomplished when one knows exactly which model is implanted, when the MRI is officially allowed for this use and when a specially trained doctor is present during examination. These conditions are already met in a few centers. You are encouraged to call for information.


I have a cardiac valve: is it safe?

Most cardiac valves are MRI compatible but older models could be a problem. You should ask your cardiac surgeon before making an appointment.


I have tattoos / piercings

Metals contained in some tattoo inks may induce heating under high field MRI. Please mention any tattoo at your arrival. All piercings should be removed before coming, if possible.


Do I really need an injection ?

Injecting contrast medium - usually a Gadolinium complex - into a vein is used to enhance lesion detection. Such information can be necessary in many situations (inflammation, tumor, blood flow disturbance, etc.). Side effects like nausea, allergy ot intolerance are extremely rare. The radiologist decides in which case injection will be beneficial for the diagnosis.