MRI of the brain: is it harmful how often can you do?
Neurologists and neurosurgeons are increasingly prescribed MRI of the head and brain for the diagnosis of diseases of the Central nervous system, operations planning and assess the quality of treatment. It happens that the study administered several times a year, sometimes with an interval of about a month. Patients are often concerned about the issue, and how safe is MRI of the head if you do it repeatedly, whether there can be negative consequences, it is justified by the doctor and how many times a year you can still hold it.
What happens when an MRI in brain tissue?
No conclusive evidence that MRI of the head may cause harm, no. During the study, the brain is in the zone of action of a powerful magnetic field, which in itself is not dangerous to humans. The magnet acts on hydrogen nuclei, mainly composed of water molecules and causes them to Orient parallel to the magnetic field, which is absolutely nothing to worry about and does not affect the function of the brain.
Apparatus for the MRI are open and closed. Magnetic resonance imaging of the closed type is the classic type open on both sides of the pipe, in which the tunnel enters the table for the patient. Many people get scared at the thought that you will need to lie still for 40-60 minutes in a tube.
Magnetic elements in the open-type scanners are not located in the tube that surrounds the patient’s body and C-shaped arc, which is moved relative to the Desk. This design with no harm and negative consequences screening in patients with claustrophobia, because only closed apparatus examined body part, so far as required, so they are not afraid.
The magnet in the MRI apparatus of the open type are generally weaker than in the tunnel, so the resolution of the resulting scans will be smaller. However, in certain situations, the open loop provides significant performance advantages.
The impression that the scanners are of the open type is less harmful and more convenient for MRI of the brain. In fact, in fact, and in another case, the study is not dangerous. Opting of the apparatus of the open type are often made in the case study in classic imaging is not possible due to claustrophobia or patient simply scared. In some cases this decision may be a compromise, since the power of the magnetic field and, hence, the accuracy of the scan of such apparatus is somewhat lower.
MRI with contrast: can the consequences be?
Magnetic resonance scan with intravenous contrast is used most often for the diagnosis of neoplastic lesions of the brain or visualizing blood vessels. This examination is administered for both diagnosis and to monitor the results of the treatment, so you have to do it more than once.
How many times you can perform an MRI with contrast with no harm to the brain? In case of complications in the form of strengthening the growth of the tumor? To do an MRI with contrast as much as is required for accurate diagnosis and development of appropriate treatment plan. The enhancement of tumor growth does not occur because ionizing radiation in the apparatus for MRI no, but the magnetic field does not damage the genetic apparatus of the cell.
Patients with kidney disease contrast may indeed cause harm. How dangerous it is to do it in each specific case can be determined only with an opinion from a General practitioner or nephrologist. Allergy to compounds of gadolinium used for the contrast enhancement is extremely rare, so for patients with a healthy urinary system is this type of MRI is not dangerous, no matter how many times it’s repeated.
Metal implants and endoprostheses
Is there a consensus what to do MRI those who have magnetic or metallic devices (cardiac pacemaker, cochlear implant), metal implants, installed titanium plates or teeth implants dangerous. In fact, implants and plates, often do not possess ferromagnetic properties, and the study in this case is dangerous only by the fact that due to interference the result can be insufficient. For each installed device, it is desirable to have an annotation or passport, which shows that it contains ferromagnetic elements and whether the patient to carry out an MRI.
Those who has a metal implant, it is important to know what material it is installed, it is best to have the annotation or passport. In this case, the doctor will be able to accurately identify possible MRI.
CT and x-ray analysis in comparison with MRI
To compare conventional radiography with MRI it is hardly possible, because the radiograph dramatically inferior to the magnetic scan in information. CT in many cases can provide enough data and is significantly cheaper, but, unlike MRI, the study is harmful to the body.
To deliver ionizing radiation, which is used to obtain x-ray images, is strictly regulated, and regulations for patients undergoing radiotherapy of tumors they are different than for healthy people. Calculating the dose, you can decide how many times during the year can be a CT or x-ray that it was not harmful.
At the same time, CT better shows bone defects and is fast. For injuries and emergencies it is also necessary to take into account. MRI for patients with loose ferromagnetic implants (clip-vessel of the brain, a vascular stent) can be dangerous to CT in this case will help solve the problem.