İntrakraniyal Anevrizma Üzerinde Oluşan Sesin Hesaplamalı Akışkanlar Dinamiği Kullanılarak Sayısal Modellenmesi

İntrakraniyal anevrizma, beyindeki bir arterin yırtılmasına ve ciddi sağlık bozukluklarına yol açabilecek bir damar genişlemesidir. Anevrizma oluşumunun kesin nedenleri hala belirsizdir; ancak bozulmuş hemodinamik parametreler ve kan akış koşullarındaki anormallikler damar genişlemesinin başlamasında rol oynar. Bu çalışmada, bozulmuş akış koşullarını ve anevrizma duvarında oluşan sesi incelemek için basitleştirilmiş bir intrakraniyal anevrizma modeli kullanılmıştır. Anevrizmaya bağlı olarak oluşan sesi belirlemek için, hesaplamalı akışkanlar dinamiği simülasyonları kullanılmış ve iç damar duvarındaki basınç dalgalanmaları incelenmiştir. Kararsız akış basınçlarını bulmak için büyük girdap benzeşimi modelleri kullanılmıştır. Sayısal akış simülasyonlarının sonuçları, anevrizma yakınındaki bölgelerde oluşan ses seviyelerinin arttığını göstermektedir. Anevrizma üzerindeki ses seviyeleri, normal damar çapına sahip bölgelerdeki ses seviyeleri ile karşılaştırıldığında, anevrizmanın ses oluşumunda 10 dB civarında bir artışa neden olduğu görülmektedir. Akış kaynaklı sesteki bu göreceli artışın, ciddi semptomlarla karşılaşmadan önce intrakraniyal anevrizmaların teşhisi açısından önemli olduğu öngörülmektedir.

Anahtar Kelimeler:

Akustik basınç, Hesaplamalı akışkanlar dinamiği, Hemodinamik, İntrakraniyal anevrizma

Numerical Modeling of the Sound Generated on an Intracranial Aneurysm Using Computational Fluid Dynamics

Intracranial aneurysm is the enlargement of an artery in the brain which may lead to rupture and result in serious health disorders. The exact mechanism of aneurysm formation is still unclear; however, the disturbed hemodynamics take part in the initiation of the vessel enlargement. In this study, a simplified intracranial aneurysm is numerically investigated to elucidate the disturbed flow conditions and the generated sound on the aneurysm wall. In order to determine the generated sound, the pressure fluctuations on the inner wall are obtained using computational fluid dynamics simulations. Large eddy simulation model is employed to find the unsteady flow pressures. The results indicate that the sound levels increase at the proximity of the intracranial aneurysm. The sound levels on the aneurysm are compared to the sound levels on the sites with normal vessel diameter, and it is seen that the aneurysm results in about 10 dB increase in the sound generation. This relative increase in the flow-generated sound is important in terms of the diagnosis of the intracranial aneurysms, which can be used as a diagnostic tool for the early detection of the aneurysm before facing with the serious symptoms.

Keywords:

Acoustic pressure, Computational fluid dynamics, Hemodynamics, Intracranial aneurysm,

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