engleski

The role of ultrasound in stroke prevention

Stroke is the third cause of death and first cause of disability in the modern society. The age limit is being shifted toward younger age groups. Since medicamentous therapy has been effective only in a small therapeutic window and associated with great risks, the importance of preventive actions aimed at stroke prevention has been Recognized. The diagnostics of macroangiopathy is important in primary and secondary stroke prevention, because macroangiopathy causes symptoms such as vertigo, transient ischemic attacks (TIA), or minor strokes. Development of neurosonology methods has made possible noninvasive investigation of the head and neck blood vessels. Extracranial color Doppler is a method used for the study of head and neck vessels in real time. Triple information is obtained, i.e. on the plaque morphology, structure and appearance; on hemodynamics, with spectral analysis of hemodynamic curves; and on spatial blood flow disturbances, circulation direction, and circulation disturbances that are color coded. During the examination, the plaque appearance, structure and surface are analyzed, and the degree of stenosis is calculated as percentage of diameter and area stenosis. In hemodynamic evaluation, systolic and diastolic blood flow velocities are measured, and different relations expressed as pulsatility and resistance indices, and relations of systolic and/or diastolic values of internal and common carotid artery are calculated. The degree of stenosis is categorized and expressed as mild, moderate or severe stenosis, pseudoocclusion and occlusion. These categories are important for planning further therapeutic procedures and dynamics of the patient follow-up. Intracranially, hemodynamic investigations of blood flow velocities in the vessels of the circle of Willis and vertebrobasilar system are analyzed. ln this way, data are obtained on hyperperfusion, development of collateral circulation in advanced extracranial stenosis, feeder vessels in blood vessel formations; and follow-up of the spasm in brain hemorrhage. The development of software has enabled simultaneous follow-up and evaluation of vasoreactivity during medicamentous or physical stimulation. It is possible to detect embolic signals in unstable carotid plaques or heart thrombus. The development of ultrasonographic techniques continues, promoting the already existing applications and introducing contrast agents. This method allows exact evaluation of the brain circulation disturbances, thus making the use of invasive methods of investigation ever more unnecessary.

ultrasound; stroke; prevention

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