Introduction
Magnetic resonance imaging, also known as MR or MRI for short, is a medical imaging procedure. The procedure works without harmful ionizing radiation. In the clinic it is used to take sectional images of the body. During the examination, the magnetic resonance tomograph generates a magnetic field as well as alternating magnetic fields which cause atomic nuclei, especially hydrogen nuclei (protons), to vibrate in the cells of our body.
Development of the cross sections
Electrical signals are generated, which can be registered by a receiver circuit. The contrast formation of different structures and tissues is based on the relaxation time and the proportion of water content of the different cell types. In the end, we measure the proportion of hydrogen atoms in the tissue structures.
Tissue types differ from each other by different proportions of hydrogen atoms. Due to the good contrast, organs, different tissues and soft tissues can be visualized very well and offer a better imaging than conventional X-rays. In the lumbar spine, the spinal cord and nerves, liquor, intervertebral discs (including herniated discs), facet joints and ligaments of the spinal column can thus be depicted particularly well.
Procedure of an MRT
Patients are informed about the exact procedure prior to the examination and must also sign a written information and consent form. If there are any further questions, please contact the trained staff or the treating physician. For the examination itself, no further preparatory measures such as laxative measures (this is not necessary for an MRI of the lumbar spine, but is necessary for an MRI of the small intestine) need to be taken the day before the examination.
Patients are asked to remove their clothing for the examination. In particular, metal objects such as jewelry, watches, piercings, hair bands and underwear with metal trimmings should be taken off, as they are attracted by the magnetic field and thus present a risk of injury. This topic might also be of interest to you: Clothing in the MRI – What do I have to wear?
Lying on the table, the patient is finally covered with a blanket and driven into the MRI scanner. Patients are informed in advance that the MRI scanner is very narrow and very loud. In consultation with the treating physician, excited and anxious patients can be given a sedative in advance to reduce anxiety.
Patients with claustrophobia should express this beforehand and, if necessary, inform themselves about the alternatives. In addition, disturbances caused by movement should be avoided at all costs so that very good pictures are produced. The patient is given headphones for protection against the volume and the various knocking noises. The patient should lie relaxed and comfortable during the examination.
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