Definition of MRI
Definition of MRI
The magnetic resonance imaging, or MRI, is to produce images of the body by placing it in a magnetic field (with a large magnet) where it is exposed to radiofrequency waves. No ionizing radiation is not used.
According to this technique, the hydrogen atoms of the living material placed in an intense magnetic field are all moving in the same direction, and then they are brought into resonance with a short time a radio wave. At the cessation of stimulation, the atoms re-emit the energy accumulated by producing a signal that is recorded by a computer system. Then the computer restores these signals as images.
The majority of devices used in medicine operate with magnetic fields above 1.5 Tesla. We're talking about high-field MRI.
Operation of the MRI
1. MRI can explore some finely tissues, especially the brain, spine and spinal cord, liver, organs of the pelvis and the structures of the knee. Thus we identify infectious or inflammatory lesions, vascular abnormalities, tumors, herniated discs, ligament or meniscal injuries ...
2. This is done without irradiating the patient and more accurate than computed tomography (CT).
3. This review is expensive, but justified when doubt persists after plain radiographs, ultrasound or CT scan.
4. Recent technical refinements of MRI, such as MRI perfusion / diffusion, can detect early signs of brain damage, in particular stroke.
What is the procedure for the patient?
You will lie on a table (usually on the back), which moves in the tunnel where the magnet. Rest assured that the claustrophobic! You have a bell to call medical personnel in case of problems, which also sees you and hears you.
The exam is long, 15 to 45 minutes on average and should not move so that the images are of good quality. Your cooperation and peace are important. In some cases they will tell you, using a microphone when stop breathing a few seconds.
The machine produces a metallic sound "impressive" for each sequence of signal acquisition. Earplugs you are provided, or music headphones. Remember to bring your own CD in the examination.
Sometimes the administration (usually intravenously in the antecubital fossa) of a non-iodinated contrast (gadolinium) is required to improve the image quality.
Risks, dangers and side effects of MRI
Magnetic fields used in MRI (more than 1500 times the Earth's magnetic field) have never caused particular consequences known to man.
The only risks are related to the presence of metals (prosthesis, pacemaker, accident debris after) they can move under the action of magnetic field. A questionnaire is given to the patient before the examination, on which it must report the presence of any foreign metallic objects into his body.
The contrast gadolinium-based is generally well tolerated. Possible allergic reactions are possible (serious accidents are exceptional), it is imperative to report making an appointment, just allergic phenomenon known: contrast media, drugs, asthma, eczema ...
This review is remarkable suffers from three major drawbacks: the strong noise, containment and duration.
The current malaise is claustrophobic! New open-field MRI are designed specifically for obese patients, claustrophobia or difficulty remaining motionless long (respiratory failure, people agitated, anxious or painful). They are still too few, a dozen, depending on the needs.
The magnetic resonance imaging, or MRI, is to produce images of the body by placing it in a magnetic field (with a large magnet) where it is exposed to radiofrequency waves. No ionizing radiation is not used.
According to this technique, the hydrogen atoms of the living material placed in an intense magnetic field are all moving in the same direction, and then they are brought into resonance with a short time a radio wave. At the cessation of stimulation, the atoms re-emit the energy accumulated by producing a signal that is recorded by a computer system. Then the computer restores these signals as images.
The majority of devices used in medicine operate with magnetic fields above 1.5 Tesla. We're talking about high-field MRI.
Operation of the MRI
1. MRI can explore some finely tissues, especially the brain, spine and spinal cord, liver, organs of the pelvis and the structures of the knee. Thus we identify infectious or inflammatory lesions, vascular abnormalities, tumors, herniated discs, ligament or meniscal injuries ...
2. This is done without irradiating the patient and more accurate than computed tomography (CT).
3. This review is expensive, but justified when doubt persists after plain radiographs, ultrasound or CT scan.
4. Recent technical refinements of MRI, such as MRI perfusion / diffusion, can detect early signs of brain damage, in particular stroke.
You will lie on a table (usually on the back), which moves in the tunnel where the magnet. Rest assured that the claustrophobic! You have a bell to call medical personnel in case of problems, which also sees you and hears you.
The exam is long, 15 to 45 minutes on average and should not move so that the images are of good quality. Your cooperation and peace are important. In some cases they will tell you, using a microphone when stop breathing a few seconds.
The machine produces a metallic sound "impressive" for each sequence of signal acquisition. Earplugs you are provided, or music headphones. Remember to bring your own CD in the examination.
Sometimes the administration (usually intravenously in the antecubital fossa) of a non-iodinated contrast (gadolinium) is required to improve the image quality.
Risks, dangers and side effects of MRI
Magnetic fields used in MRI (more than 1500 times the Earth's magnetic field) have never caused particular consequences known to man.
The only risks are related to the presence of metals (prosthesis, pacemaker, accident debris after) they can move under the action of magnetic field. A questionnaire is given to the patient before the examination, on which it must report the presence of any foreign metallic objects into his body.
The contrast gadolinium-based is generally well tolerated. Possible allergic reactions are possible (serious accidents are exceptional), it is imperative to report making an appointment, just allergic phenomenon known: contrast media, drugs, asthma, eczema ...
This review is remarkable suffers from three major drawbacks: the strong noise, containment and duration.
The current malaise is claustrophobic! New open-field MRI are designed specifically for obese patients, claustrophobia or difficulty remaining motionless long (respiratory failure, people agitated, anxious or painful). They are still too few, a dozen, depending on the needs.
MRI - Useful Information
Which requires the consideration how much it costs, how is it paid?
Prescribed by a doctor, an MRI "classic" for the technical costs 213.71 euros, which we must add 73 euros fee for the radiologist. Beware timeout appointment. They are sometimes very long due to the lack of machines (507 to 30 June 2007) compared to the needs.
The Health Insurance supports 100% of the technical part, and reimburses 70% of the doctor's fee ... however, if the patient has followed the chain of care: physician and specialist. The remaining 30% is reimbursed by the insurer or mutual.
Where practical examination and by whom?
MRI is performed in medical imaging center by specialized technicians, under the direction of radiologists.
Which requires the consideration how much it costs, how is it paid?
Prescribed by a doctor, an MRI "classic" for the technical costs 213.71 euros, which we must add 73 euros fee for the radiologist. Beware timeout appointment. They are sometimes very long due to the lack of machines (507 to 30 June 2007) compared to the needs.
The Health Insurance supports 100% of the technical part, and reimburses 70% of the doctor's fee ... however, if the patient has followed the chain of care: physician and specialist. The remaining 30% is reimbursed by the insurer or mutual.
Where practical examination and by whom?
MRI is performed in medical imaging center by specialized technicians, under the direction of radiologists.
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