MRI of the brain: what the survey shows?
The development of medicine enabled the shift from invasive, often paired with a deadly danger, and diagnostic procedures to noninvasive and safe imaging techniques of the brain. One of the most common methods of diagnosis, providing accurate and detailed information to date is magnetic resonance imaging (MRI). The results of brain MRI can detect pathological changes in the early stages, which gives a chance to prevent the aggravation of the disease and to carry out timely treatment.
Description of the diagnostic method
MRI allows to obtain cross-sectional image of the internal structure of the skull. The technique is based on the ability of brain tissue to give the electromagnetic response when exposed to body wave pulses. With the help of special equipment – a tomograph is determined by a combination of signals and the measured reflected energy received by the protons – the atomic nucleus of hydrogen.
The varieties of surveys
There are several specialized types of surveys on the CT scan. Describe the main types in more detail.
Mr cisternography and liquorrhea
Non-invasive technology that allows you to get a «picture» of cerebrospinal fluid spaces, without the artificial enhancement of the subarachnoid cisterns (extended receptacle of cerebrospinal fluid in the subarachnoid space). This kind of magnetic resonance imaging administered to study the structure and functional capacities of the CSF system, the main purpose of which is excretion from the human brain of waste products.
A more informative examination: Mr liquorrhea is a method that is directly linked to the natural cycle of cardiac activity. The only way to objectively assess the hydrodynamic characteristics in liquor space.
Technology shows the image of vascular structures through the scanner. This survey gives you the opportunity to visually assess the condition of the circulatory system of the brain without injection of contrast. However, in some situations, for more detailed information and the final report requires the use of special contrast agents on the basis of the magnetizable elements of paramagnetic materials.
Diffusion-weighted magnetic resonance imaging
The most used method of research to identify ischemic brain lesions. The image obtained by this method shows the localization of the lesion in the acute stage of ischemic stroke that gives the chance to carry out remedial measures during the period of the therapeutic window – the range favorable for tissue regeneration.
Using Mr-perfusion can be considered to quantify the circulating blood volume within the brain. The method shows the relative volume of blood flow in the body and allows one to estimate the rate of passage of blood through the smallest vessels – the capillaries. A survey carried out for diagnosis of malignant tumors of the brain, especially when the task is to obtain quantitative data on blood flow in a particular Department.
This method of examination is recognized as the most promising technique to identify local foci of epilepsy, as its main purpose is to identify areas of the brain that show activity in response to the action of certain external stimuli. This type of magnetic resonance imaging can identify the location of brain areas responsible for motor activity, speech, vision, memory and are unique to each person.
Magnetic resonance spectroscopy
This study allows without the use of invasive technology and without damage to the examined patient to obtain authentic data on the chemical composition of the brain tissue. The method is based on the fact that when a particular type of disease changes the concentration of certain biologically active substances in the tissues of the brain.
Indications for MRI of the brain
If the physical examination by a neurologist there is a suspicion for the presence of pathologies that affect the Central nervous system, after performing standard clinical trials: General and biochemical blood analysis, the doctor prescribes examination on the CT scan. The results of magnetic resonance imaging allow to make the accurate conclusion to confirm or refute the assumption about the development of various diseases, including:
- brain tumor;
- vascular disease and malformations (stenosis, thrombosis, aneurysms, angiomas, telangiectasia);
- acute critical condition (cerebral infarction, cerebral hemorrhage by the type of hemorrhagic infarction or hematoma, hemorrhage in the subarachnoid space, cerebral infarction);
- infectious and degenerative processes (abscess, meningitis, encephalitis, parasitic lesions, multiple sclerosis, Alzheimer’s disease).
Interpreting the results of MRI will help to differentiate the effects of head injuries: bone fractures, extracerebral and subdural hematomas, and traumatic subarachnoid hemorrhage.
Transcript of MRI in cases of suspected neoplasm of the brain
The purpose of the scoping study of CT – primary measure in cases of suspected neoplasms of the brain. The results of the survey allow to determine the nature, location, stage of the tumor. Here are the main examples of deciphering a doctor’s opinion.
Astrocytic glioma in T1-weighted images show Hypo-formations. If the scanner operates in the mode of T2 – astrocytoma looks hyperintense area. When using a contrast agent heterogeneity is expressed as T1 images and T2 images. Transcript data for the differentiation of ependymomas based on their localization and morphological features.
For papillomas of the choroid plexus is characterized by intense asymmetric MRI -manifestation of entities with well-delineated contours and a form of «cauliflower».
The results of imaging in the examination of metastatic tumors most objective if the study was conducted with contrast enhancement. In this case, a more reliable decoding of images that allow to determine the localization of metastasis and number of tumor sites.
Meningiomas irrespective of their histological type in most cases look Hypo to the cerebral cortex. The results obtained in the T2 mode of the imager are characterized by their variability.
When great extent survey mode T1 MRI shows low intensity, however, T2-mode angioretikulez demonstrate higher activity. As a rule, after application of the contrast signal from hemangioblastoma increases.
The results of magnetic resonance imaging differentiate the different brain tumors, including:
- primary lymphoma;
- tumors of the brain stem;
- extracerebral tumor.
To date, the recommendation to implement a review of magnetic resonance imaging – rational and adequate treatment of even the relatively healthy person in the absence of specific clinical symptoms. Interpreting the results of imaging allows you to choose the correct treatment strategy, provides an opportunity to monitor and make adjustments to the applied therapy program.