Diagnosis of many diseases is significantly complicated by the fact that to accurately determine the problem, it is necessary to see the features of external changes in the tissue, a change in its structure. It is in such cases that the optimal diagnostic method is magnetic resonance imaging (MRI).
What is magnetic resonance imaging?
Imaging with MRI is very common today, since it allows you to visualize almost all internal organs and identify structural changes in tissues and organs; in particular, layered MRI images of the brain are very informative and very helpful in the diagnosis of intracranial oncological neoplasms, strokes (the ability to see the focus in hemorrhagic stroke), as well as vascular pathology (aneurysms, or malformations) is especially valuable; MRI is also necessary for severe traumatic brain injuries.
Method Advantages
The MRI method combines visual and indicative, 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, with the aim of more detailed visualization, contrast enhancement is used; in particular, this is applicable in the study of pathology of cerebral vessels. Brain MRI images with contrast are very informative in case of acute cerebrovascular accident, as they make it possible to track the level of vascular lesion and the exact size of the pathological focus.
How does a tomograph work?
Under the influence of 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 released.
The diagnostic MRI technique works based on the phenomenon of magnetic resonance. The principle of operation of diagnostic equipment a consists in the transformation of 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 health.
Having already received the finished picture, doctors of the corresponding profile analyze the resulting image, compare with the norm and identify pathological changes.
Method History
The phenomenon of nuclear magnetic resonance itself was discovered and described as early as the middle of the twentieth century - in 1946. And the first time to get an image using this technology was possible in 1973.
How is the examination
Externally, the apparatus for magnetic resonance imaging looks like a rather narrow long tube.
When examining a patient, they are placed inside the building using a special couch.
Since the duration of the patient’s stay inside the device is quite large - up to forty minutes, and in some difficult cases even longer, the conditions for the patient’s stay in the “tube” should be as comfortable as possible. Indoor lighting and ventilation are maintained inside the unit, sufficient to ensure a calm breathing. Without fail, inside the device there should be a button for communication with the operator conducting the examination.
Preparation
- MRI should not be done on a full stomach.
- Before the examination procedure, the patient must remove all metal things (watches, jewelry, hairpins, removable dentures).
Throughout the procedure, the patient is forced to lie as motionless as possible, since an image is formed during the study; 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 put their mother in the tomograph together with him.
Survey results
An 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 receives a printed MRI image in his hands, reflecting the main, key images, as well as a form with the conclusion of a specialist.
For convenience, in many cases, the patient’s hands are also given a disk with all, without exception, images obtained during the procedure. This nuance is very important in cases where in the future the patient will seek other specialists to decrypt the data obtained during the diagnosis.
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;
- organs of the chest and abdominal cavity;
- of cardio-vascular system.
It is also used to diagnose pathological changes in these organs and systems.
Indications are situations when, for the diagnosis of traumatic injuries, the information provided by the x-ray image is not enough.
MRI is necessary in cases where there is a suspicion of structural pathology of tissues or organs.
A feature of the method is that in the study of soft tissues, this technique is significantly more effective.
Not investigated using tomography:
- Bone.
- Lung tissue.
- Stomach and all parts of the intestine.
Contraindications and limitations
The method of magnetic resonance imaging is quite safe and has no age-related contraindications. However, a number of contraindications still exist:
- Given the specificity of this diagnostic technique, it is contraindicated in patients who have any metal 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. joint prostheses
- Significant difficulties are presented by magnetic resonance imaging in patients with epilepsy and other diseases for which episodes of loss of consciousness are typical.
- It is difficult in some cases and such a feature as overweight.
The following cases can be distinguished into the group of relative contraindications:
- The earliest stages of pregnancy.
- Decompensated stage of heart failure.
- Presence of prostheses of blood vessels or heart valves.
- The presence of tattoos with metal pigments.
Diagnosis of brain pathology
When it comes to diagnostic examination of the brain, magnetic resonance imaging (MRI) is the most informative type of examination.
In fact, MRI images of the brain are photos of its layers.
Therefore, thanks to this diagnostic technique, the most detailed study of the substance of the brain and the identification of pathologies at the earliest stages becomes possible.
MRI images of the brain must be taken in the following cases:
- Acute cerebrovascular accident.
- Severe traumatic brain injury. In case of 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 you to visualize not only the bones of the skull, but also the condition of the intracranial structures.
- Signs of intracranial hypertension. In this situation, the exclusion or identification of intracranial volumetric education significantly facilitate layered images. Brain MRI for hypertension syndrome is prescribed to confirm such diagnoses as intracranial hematoma, intracranial tumors, brain abscess.
- Anomalies in the development of cerebral vessels.
- Condition monitoring after neurosurgical surgery.
- A detailed MRI scan will help to establish the localization and (with repeated studies) the dynamics of the development of neuromas and cystic formations.
Diagnosis of spinal pathology
Magnetic resonance imaging provides the broadest possibilities for the diagnosis of pathological conditions of the spine.
The result of the diagnostic procedure will be a detailed layered image.
MRI of the thoracic spine is prescribed according to the following indications:
- Pain syndrome of unknown etiology in the chest area - to exclude primary oncological formations or metastatic lesions.
- Neurological symptoms allowing intervertebral hernia.
- The procedure is applicable both before and after surgery - to control the dynamics of recovery processes.
- Injury with suspected fracture of the chest - to exclude bone damage. Since the tomogram provides a detailed layered image, it is more informative in these situations than an x-ray.
MRI of the lumbar region has diagnostic value in the following cases:
- Complaints of pain in the lumbosacral region, with insufficient effectiveness of the radiographic examination.
- After injuries in this area - to exclude bone-traumatic injuries.
- With a diagnosed spinal fracture complicated by displacement of fragments - to clarify the degree of displacement, to exclude damage to the intervertebral cartilage, meninges and spinal cord.
- For differential diagnosis of degenerative changes in the spine and destruction of the vertebrae as a result of metastatic lesions.
- Neurological symptoms indicating irritation or compression of the nerve root require clarification of the cause of compression; in this case, to diagnose a case of vertebral displacement, it is enough to take an X-ray. Spinal MRI should be performed to identify pathology from non-radiopaque tissues (displacement of the intervertebral disc, herniated disc, inflammatory edema, compressing the nerve root, neoplasm causing compression).