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Brain MRI
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A brain MRI takes pictures of the brain using a magnetic field, meaning a very powerful magnet, together with radiofrequency pulses, which are radio waves sent out in short bursts. It does not use X-rays. Inside the body there are hydrogen nuclei, the centers of those atoms, and the magnetic field lines them all up facing the same way, like compass needles settling into a single direction.
Then the radiofrequency pulse comes in and knocks that alignment out of place. As the nuclei return to the way they were before, they give off a signal, and that signal is what the machine turns into an image. Because each tissue answers back with a slightly different signal, MRI can tell the structures of the brain apart in fine detail, among them the gray matter and the white matter.
In brief
A brain MRI creates images using a magnetic field and radiofrequency pulses; it does not use X-rays.
Because the signals differ from tissue to tissue, MRI can show brain structures in fine detail, including white matter and gray matter.
The magnetic field aligns hydrogen nuclei. A radiofrequency pulse changes that alignment, and as the nuclei return to their original state, they give off signals that are converted into images.
The image comes from a physical sequence: align, disturb the alignment, detect the return signal, and convert it into visible anatomy.
Sources (1)
- National Institute of Biomedical Imaging and BioengineeringMagnetic Resonance Imaging (MRI)
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated