CNS Magnetic Resonance Imaging

CNS Magnetic Resonance Imaging

Medical imaging (also commonly called body imaging) is known to refer to all the processes and techniques that are applied in order to obtain medical pictures of the human organism (or of certain parts of the human body) which can be of great importance for various clinical purposes (medical procedures that examine a certain clinical condition or diagnose it). CNS Magnetic Resonance Imaging is a common medical imaging technique which uses a special instrument called a MRI scanner; this type of medical apparatus employs powerful magnets which excite and polarize the single protons (hydrogen nuclei) of the human tissues’ water molecules. This process yields a special signal that is detected by the MRI scanner, and then spatially encoded in body images.

CNS Magnetic Resonance Imaging has been used since the beginning of the ’80s. No side effects due to repeated or long term exposure to the magnetic fields employed in this type of clinical procedure have been determined so far. As you have probably figured out, this widely employed clinical technique is able to help the physician set a clear diagnosis in case the patient is suffering from a CNS (central nervous system) medical condition – disorders that can affect any component of the patient’s brain (the cerebellum, the brain stem, the diencephalon, the cerebral hemispheres) and the individual’s spinal cord.

All patients must always keep in mind that their personal health care specialist may ask them to undergo this type of medical procedure (CNS Magnetic Resonance Imaging) for a reason which has not been mentioned in this chapter. It is imperative to always follow your PD’s instructions concerning any medical aspect. In case you want to know more about the reasons for which one may be advised to undergo this type of imaging technique you should refer to your main medical professional.

CNS Magnetic Resonance Imaging Description

MRI (including CNS Magnetic Resonance Imaging) mainly employs 3 types of electromagnetic fields: a very powerful static magnetic field, a weaker magnetic field (the intensity of this field varies in time) and a weak RF field (radio-frequency field). The human organism is composed of water molecules; each molecule of this type contains 2 protons (hydrogen nuclei). When a patient enters the MRI scanner’s powerful magnetic field, the hydrogen nuclei (the protons) align within the given direction of the magnetic field. When the RF field is turned on it allows the hydrogen nuclei to absorb a part of its energy; as soon as it is turned off, the hydrogen nuclei release the absorbed energy at a RF which is captured and processed by the MRI scanner. The applying of additional magnetic fields during the examination helps create the clinical image. Diseased masses of tissue can be detected due to the different rates in which the protons return to their initial state of equilibrium.

Magnetic Resonance Imaging is known to create a 2D imagine of a slice of the patient’s organism; this is why it is considered a type of tomography. The modern MRI scanners are able to create 3D block images, which can be seen as a generalization of the tomographic, single-slice concept. CNS Magnetic Resonance Imaging does not employ ionizing radiations; in other words it is not associated with the same medical risks as CT (no long term effects are though to arise after the exposure to strong static fields, although this concept is still strongly debated among scientists; this is why the number of scans which a person can undergo does not have a limit). However, this does not mean that exposure to a radio-frequency field is unable to produce any health risks.

The main idea is that CNS Magnetic Resonance Imaging manages (with the help of a set of powerful magnets) to detect the body’s magnetic molecules. These molecules can be either endogenous, or can be special magnetic substances which have been injected in one of the patient’s veins (through a catheter). FMRI (Functional Magnetic Resonance Imaging) especially analyses the changes that affect hemoglobin’s magnetic properties while it carries the molecules of oxygen. 

CNS Magnetic Resonance Imaging Related Medication

Like most other body imaging techniques, this type of medical examination requires the administration of a special magnetic resonance contrast media. In this chapter we will try to familiarize you with a set of generic information about one of the most common contrast agents that can be employed under the given circumstances. Magnevist is one of the most widely known substances that can be used as a contrast media for a CNS Magnetic Resonance Imaging procedure. It can be purchased under the generic name of Gadopentetate Dimeglumine.

What makes Magnevist appropriate to use during this type of body imaging procedure is the fact that it is able to produce magnetic effects. However, as with most other medical substances (and other contrast agents), the administration of this product is associated with a number of risks, some of them quite severe. For example, the use of Magnevist as a contrast agent for CNS Magnetic Resonance Imaging can lead to the development of a dangerous disorder (which can even threaten the patient’s life) in the case of patients who suffer from an advanced form of kidney disorder. The symptoms of this severe medical condition include: muscle weakness, swelling, itching, burning and hardening of the skin, stiffness or pain of the feet, legs, hands or arms, yellow patches that develop on the whites of the patient’s eyes, skin discoloration or skin redness, and so on. This is why it is very important for all patients who consider undergoing CNS Magnetic Resonance Imaging (which requires the administration of Magnevist) to inform their medical prescriber if they are suffering from kidney disorder.

The presence of kidney disease is not the only contra-indication which can be associated with the administration of Gadopentetate Dimeglumine as part of the CNS Magnetic Resonance Imaging procedure, as patients who have been diagnosed with the presence of a seizure medical condition, who suffer from allergies or from asthma should also avoid being administered Magnevist or any similar substances. The same advice is valid in the case of patients who are on dialysis or in the case of individuals who have a medical history of stroke and / or blood clots. This is the only way in which you can make sure that you will not experience any unwanted (potentially dangerous) adverse manifestations or delayed effects due to your being administered Magnevist.