Theoretical model of intracranial media ultrasonic attenuation measurement method

The state of intracranial media (IM) and an intracranial pressure (ICP) as its characteristic depends on the relations of the intracranial components’ volumes and their changes. [1,2]. Intracranial components (brain tissue, blood, cerebrospinal fluid (CSF)) are characterized by different acoustic parameters, such as ultrasound speed and frequency dependent attenuation. We have shown in our previous work that the volume changes of these components can be measured by ultrasonic time-of-flight method [3]. In this work [3] we have shown, that by applying simultaneous measurement of the signal’s time-of-flight through IM and the ultrasound attenuation in IM, it is possible to obtain information about the character of the physiological phenomena that occur in IM. For example, in the cases of cerebral vasodilatation and swelling phenomena that cause the increase of ICP, the decrease of signal’s time-of-flight through IM is observed. Therefore, the changes of attenuation in IM are of the opposite signs, i. e. in the case of the swelling phenomenon, the attenuation increases, and in the case of the vasodilatation phenomenon the attenuation decreases [3]. Besides, various reactions of time-of-flight and attenuation can be observed during the occurrence of physiological phenomena, by choosing different acoustic paths through IM. Additional information about the ultrasound attenuation in IM is supposed to allow choosing more optimal measurement acoustic path and give more exact interpretation of the physiological phenomena measured. The aim of this study is to create a mathematical model of ultrasonic attenuation measurement in the intracranial media that could be realized by the non-invasive ultrasonic time-of-flight methods and to perform analysis of possible components of the uncertainty of measurement.