MRI - magnetic resonance & open MRI
The FRZ info service
How does an MRI work
We know that magnetic fields align metal chips. You can certainly remember various attempts at school with a permanent magnet. Well - there are many substances, more precisely molecules, that react to magnetic fields. Of course, this depends on how strong the magnetic field is. In order to generate a reaction - a measurable reaction - in the human body, the water molecules are aligned. In truth, it is the complex physical properties of the atoms that are exploited. But to simplify it and make it understandable for you, we will spare ourselves the explanation of this physical part.
Imagine that each molecule has its own angular momentum and rotates around its own axis - similar to a top that is upright when it rotates around its own axis at sufficient speed. In the case of molecules, it is the nucleus that rotates, which is why the MRI is also called nuclear spin - spin is the English word for rotation. A strong magnetic field now influences this rotation and aligns the molecules.
If the magnetic field is switched off, the core tries to get back to its original position and rotation. "Diseased" tissue behaves differently than "healthy" tissue. The computer then calculates data from the differences that are measured and uses it to create the images that you and the doctor can see. So much for a simplified explanation of the MRI.
The big and really considerable advantage of an MRI is the fact that it does not work with X-rays or other ionizing radiation. In addition to the bone structure, soft parts - i.e. other tissue - can also be made visible. The accuracy and the resolution of the MRT images are therefore also a relevant advantage compared to a CT examination. Sometimes it makes sense to do an MRI directly and to save a CT examination.
What are the advantages of an open MRI
In contrast to a conventional MRI, the patient in an open MRI does not lie in a tube. The tightness of a tube coupled with the background noise of an MRI creates a feeling of claustrophobia in many patients. During the examination in an open MRI, the patient can: Enjoy the wide view inside because the patient area is almost three times as large as in a conventional MRI. This width also enables examinations in overweight patients: inside and children.
The space resulting from the size of the examination area also has a positive effect on the patient: inside. Less stress means less tension in the body and thus better image quality. This makes the diagnosis a lot easier and produces a better result.
Is the technique less good in an open MRI?
Basically, a magnetic field is created that affects the alignment of the water molecules in the body. Radio waves that are emitted are then reflected and special coils pick up these signals. The magnetic field of an open MRI is vertical and perpendicular to the patient's body axis: inside. This is the reason for the use of much more effective "receiving coils" than with conventional tunnel devices. This makes it possible to work with less magnetic field strength and still obtain image quality as with conventional devices with a similar or slightly higher magnetic field strength. Basically, of course, the higher the magnetic field strength, the higher the quality of the image.