Computational Modeling and Investigation of the Vibro-Acoustic Effects Induced by Intracranial Stenosis in a Simplified Head Model

Abstract

Purpose Intracranial stenosis is a critical cardiovascular disorder which may lead to recurrent ischemic stroke. The flow in a stenosed artery tends to have a chaotic pattern, resulting in fluctuating pressures on the artery wall. These acoustic pressures are known as the sources of arterial noise and vibration. The generated vibro-acoustic signals on the stenosed artery propagate through the surrounding body tissues and reach the epidermal surface. In this study, the stenosis-induced vibration on the epidermal surface is aimed to be utilized for the diagnosis of occlusion in the intracranial artery. Methods An intracranial stenosis is modeled considering a simplified head geometry consisted of brain, skull, and skin. The simplified head model has an idealized spherical form. Three different stenosis severities are employed to elucidate the effects of mild, moderate, and severe intracranial stenosis. ADINA finite element analysis software package is used to perform harmonic and modal analyses to determine the biodynamic responses on the epidermal surface of a human head. Results According to the results obtained, vibration amplitudes on the epidermal surface tend to increase with increasing stenosis severity. The stenosis-induced effects on the vibration responses are particularly prominent in the frequency range of 400-1000 Hz. Abnormal increase in vibration amplitudes between 400 and 1000 Hz can be an indicator of further occlusion in the intracranial artery. Conclusions The stenosis-induced vibro-acoustic effects provide important clues about arterial health. Excessive vibration amplitudes indicate a potential arterial occlusion and can be used as an early diagnostic tool for intracranial stenosis detection.