MRI in stroke: types that will show research?
Acute cerebrovascular accident (CVA) is the most common form of emergency, and also one of the most serious health and social problems of our time. To violations of blood circulation in the brain include:
- Ischemic stroke or heart attack.
- Bleeding into brain tissue, or hemorrhagic stroke.
- Hemorrhage under the membranes of the brain.
In addition, there are mixed types: hemorrhage under the membranes of the brain and in the substance of the brain, the simultaneous formation of ischemic and hemorrhagic foci in the brain. All of these reasons pathology combines the term «stroke».
Modern imaging techniques and descriptions are the most reliable ways to diagnose the type of stroke. In the early stages since the stroke, they allow you to choose an effective therapeutic strategy.
In ischemic type of stroke (cerebral infarction) the use of MRI in 80 – 90% of cases accurately identifies areas of hyperintensity after 4-6 hours from the onset of the cerebral accident. In the following hours, up to two days the area of hyperintensional expanding even more. With Mr angiography in the first hours on the tomograms are visible signs of bleeding around the ischemic zone, which confirms the fact that stroke (heart attack). In case of hemorrhage in the area of damage after a day in 30-35% of cases is determined by the local signal enhancement.
In contrast to Mr-imaging, with CT signs of infarction in areas with low density are determined in half of the cases only after 12 hours from the onset of ischemic stroke. Moreover, lesions in the brain stem and lacunar infarctions are determined only by CT with the introduction of contrasting drugs, that is unsafe due to the toxicity for the brain of these substances.
Thus, MRI is a method that’s more effective in the early stages of diagnosis of lacunar infarction than CT.
Please note that lacunar strokes are «clinically silent», i.e., are asymptomatic. But contrary to popular misconception, lacunar stroke – a dangerous form of stroke, with severe consequences. Due to the erased clinical picture of lacunar stroke is not diagnosed and not treated on time. Such multiple lacunar strokes can lead to dementia and cognitive disorders.
Hemorrhagic saturation, i.e. bleeding in the brain previously diagnosed on CT with contrast enhancement and helical CT.
Already after six, maximum of ten hours after a hemorrhagic stroke on CT scan visualized a lesion with increased density, where is the hemorrhage. And, in less than twelve hours after the incident hemorrhagic stroke, around large foci of hemorrhage can recognize the signs of swelling, which is seen as an oval low density. MRI data in the first hours after a hemorrhagic stroke are not sufficient to identify it as the MRI picks up signals from the blood as well as from white matter. At a later time magnetic resonance imaging in hemorrhagic infarction detects the location of the lesion and the amount of vascular anomalies, which eliminates the classic angiography with use of contrast agents, which have toxic effects on the brain. The data of CT and MRI in combination with indicators of severity of condition of patients, are factors determining the need for surgical interventions after hemorrhagic stroke.
Subarachnoid hemorrhage (SA) in the lesion diagnosed by CT and magnetic resonance imaging, particularly with CT and contrast-enhanced Mr angiography, 95% of patients within the next half of the day. Such studies can establish the location and extent of hemorrhage, and infiltration of blood into the substance of the brain.
In the later stages, MRI is more informative than CT. Repeated studies of MRI allow to judge about the dynamics of narrowing of the blood vessels, complications, and the timing of the formation of coronary lesions and their extent. The MRI results are one of two defining reference points for the solution of the question of a possible operational (surgical) treatment of subarachnoid hemorrhage, due to rupture of arterial aneurysms and arteriovenous malformations. The second landmark is the patient’s condition.
CT with contrast enhancement, spiral CT and Mr angiography are replacing standard angiography with the introduction of contrast agents. The latter is used only in the absence of hospital CT and MRI. In addition to the diagnosis of type of stroke-the classic and modified methods CT and MRI provide the opportunity to distinguish acute impairment of cerebral blood flow (stroke), tumors, brain abscesses, post-traumatic epidural and subdural hematomas.
Acute violation of cerebral circulation, which you won’t even notice
A minor stroke with less pronounced symptoms, as dangerous to human life, and lacunar. In fact, it’s the same stroke, but affecting smaller vessels in the center and leaks with no visible effects to the patient. A minor stroke — Wake-up call to the fact that the vascular system in the future can give such failure, which will not pass unnoticed.
The only evidence of the incident of stroke are facial asymmetry, visual disturbances. People may suddenly begin to speak incoherently, to stutter, not to respond to questions of others. If you suspect symptoms of stroke in themselves or a loved one, it is urgent to consult a doctor.
MRI is the only effective diagnostic tool in the search of mini-strokes. It is able to show petechial hemorrhages in the brain. At the same time a survey of the cardiovascular system, because pathology of these organs is the cause of mini-strokes.
In some cases, the etiology of stroke may be disruptions in the microvasculature caused by syphilis, rheumatism. If the specialist suspects one of these diseases, it also diagnose it to detect the etiology of stroke.
Familiar to all, but such a dangerous disease Despite the high prevalence (almost everyone has a friend or relative undergoing ischemic attack or minor stroke) and a study, this disease is deadly! It is difficult to treat and requires a long rehabilitation period. Remember, the sooner a stroke is diagnosed and therapy begun, the better the chance to return to working life!