Diagnosis of many diseases is significantly hampered by the fact that in order to accurately determine the problem, it is necessary to see the features of external tissue changes, changes in its structure. It is in such cases that magnetic resonance imaging (MRI) is the best diagnostic method.
What is magnetic resonance imaging
Visualization through MRI today is very common, because it allows you to visualize almost all internal organs and identify structural changes in tissues and organs; in particular, layered brain MRI images are very informative and very helpful in diagnosing intracranial oncological neoplasms, strokes (the ability to see the focus in hemorrhagic stroke is especially valuable), as well as vascular pathology (aneurysms, or malformations); an MRI is also necessary for severe traumatic brain injuries.
Method benefits
The MRI method combines visibility and indicativeness, but at the same time safety for the patient.
The indisputable advantage of MRI is that such detailed, clear, detailed images of internal organs and tissues can be obtained without the use of contrast agents.
However, in some cases, for the purpose of more detailed visualization, contrast enhancement is applied; inin particular, this is applicable in the study of the pathology of cerebral vessels. MRI images of the brain with contrast are very informative in acute disorders of cerebral circulation, as they make it possible to track the level of vascular damage and the exact size of the pathological focus.
How a tomograph works
When exposed to magnetic vibrations, the behavior of hydrogen atoms changes, since the mode of motion of a positively charged particle in the nucleus of a hydrogen atom changes. When the movement stops, the energy recorded by the device is emitted.
The diagnostic technique of MRI works on the basis of the phenomenon of magnetic resonance. The principle of operation of diagnostic equipment is to transform radio signals into a picture. And the converted radio signal is obtained from a magnetic resonance spectrometer.
Due to the properties of hydrogen atoms, the content of which in the human body reaches ten percent, such a diagnosis becomes possible without the slightest harm to he alth.
After receiving the finished image, doctors of the appropriate profile analyze the resulting image, compare it with the norm and identify pathological changes.
History of the method
The very phenomenon of nuclear magnetic resonance was discovered and described in the middle of the twentieth century - in 1946. And for the first time, it was possible to obtain an image using this technology in 1973.
How the examination works
External MRI machinelooks like a rather narrow long pipe.
In the examination, the patient is placed inside the facility using a special couch.
Since the duration of the patient's stay inside the apparatus is quite long - up to forty minutes, and even more in some difficult cases, the conditions for the patient's stay in the "pipe" should be as comfortable as possible. The interior of the apparatus is maintained with soft lighting and sufficient ventilation to ensure quiet breathing. Without fail, inside the device there must be a button for communicating with the operator conducting the examination.
Preparation
- An MRI procedure should not be performed on a full stomach.
- Before the examination procedure, the patient must remove all metal items (watches, jewelry, hairpins, removable dentures).
During the entire procedure, the patient is forced to lie as still as possible, because during the study an image is formed; and the clearer it is, the more accurate and better the diagnosis will be. In this regard, in cases where there is a need to conduct a tomographic examination of a small child, specialists are forced to place the mother in the tomograph together with him.
Survey results
MRI image is a series of images that are layered images of internal organs.
The result of a tomographic examination is usually ready a few hours after the diagnostic procedure.
The patient gets onhands a printed MRI image, reflecting the main, key images, as well as a form with a specialist opinion.
For convenience, in many cases, the patient is also given a disk with all, without exception, the images obtained during the procedure. This nuance is very important in cases where in the future the patient will apply for decryption of the data obtained during the diagnosis to other specialists.
Indications for tomography
This technique helps to visualize the state and structure with a high degree of accuracy:
- brain and spinal cord;
- spine and joints;
- intervertebral discs;
- thoracic and abdominal organs;
- cardiovascular system.
It is also used to diagnose pathological changes in these organs and systems.
Indications are also situations where the diagnosis of traumatic injuries is not enough information that X-rays give.
MRI is necessary in cases where there is a suspicion of structural pathology of tissues or organs.
The peculiarity of the method lies in the fact that this technique is much more effective in the study of soft tissues.
Not examined by tomography:
- Bone tissue.
- Lung tissue.
- The stomach and all parts of the intestines.
Contraindications and restrictions
The method of magnetic resonance imaging is quite safe and agehas no contraindications. However, a number of contraindications still exist:
- Taking into account the specifics of this diagnostic technique, it is contraindicated in patients with any metallic inclusions in the body, say, implants (for example, in the cranial cavity), etc.
- Also, a contraindication for magnetic resonance imaging is the presence of a pacemaker in the patient.
- With great care, patients with prostheses should be examined; e.g. prosthetic joints
- Significant difficulties present magnetic resonance imaging in patients with epilepsy and other diseases, which are typical episodes of loss of consciousness.
- Represents difficulty in some cases and features such as being overweight.
The following cases can be distinguished in the group of relative contraindications:
- Earliest pregnancy.
- Decompensated stage of heart failure.
- Presence of prosthetic vessels or heart valves.
- Presence of tattoos with metallic pigments.
Diagnosis of brain pathology
When it comes to the diagnostic examination of the brain, magnetic resonance imaging (MRI) is the most informative type of examination.
Essentially, MRI scans of the brain are photos of its layers.
Therefore, thanks to this diagnostic technique, the most detailed study of the substance of the brain becomes possibleand detection of pathologies at the earliest stages.
MRI images of the brain should be done in the following cases:
- Acute cerebrovascular accident.
- Severe traumatic brain injury. With a traumatic brain injury, it is customary to take an x-ray of the head to exclude a fracture of the skull bones. MRI, however, will allow visualizing not only the bones of the skull, but also the state of intracranial structures.
- Signs of intracranial hypertension. In this situation, the exclusion or detection of an intracranial mass is greatly facilitated by layered images. MRI of the brain in hypertension syndrome is prescribed to confirm such diagnoses as intracranial hematoma, intracranial tumors, brain abscess.
- Abnormal development of cerebral vessels.
- Monitoring the condition after neurosurgical surgery.
- A detailed MRI scan will help and establish the localization and (with repeated studies) the dynamics of the development of neurinomas and cystic formations.
Diagnosis of spinal pathology
Magnetic resonance imaging provides the broadest possibilities for diagnosing pathological conditions of the spine.
The result of the diagnostic procedure will be a detailed layered image.
MRI of the thoracic spine is prescribed for the following indications:
- Pain syndrome of unknown etiology in the chest area - to exclude primary oncological formations or metastatic lesions.
- Neurological symptoms suggestive of a herniated disc.
- The procedure is applicable both before surgery and after it - to control the dynamics of recovery processes.
- Injuries with suspected chest fracture - to exclude bone damage. Since a tomogram provides a detailed layered image, it is more informative in these situations than an x-ray.
MRI of the lumbar region is of diagnostic value in the following cases:
- Complaints of pain in the lumbosacral region, with insufficient effectiveness of x-ray examination.
- After injuries of this area - to exclude bone-traumatic injuries.
- In case of a diagnosed fracture of the spine, complicated by displacement of fragments - to clarify the degree of displacement, exclude damage to the intervertebral cartilage, meninges and spinal cord.
- For the differential diagnosis of degenerative changes in the spine and destruction of the vertebrae as a result of a metastatic lesion.
- Neurological symptoms indicating irritation or compression of the nerve root, clarification of the cause of compression is required; in this case, to diagnose the case of displacement of the vertebrae, it is enough to take an x-ray. An MRI of the spine should be performed to detect pathology from non-radiocontrast tissues (displacement of the intervertebral disc, disc herniation, inflammatory edema that compresses the nerve root, neoplasm that causes compression).
