Magnetic Resonance guided Focused Ultrasound (MRgFUS) is a non-invasive technique based on the thermal ablation of a target using high intensity focused ultrasound. MRgFUS treatment applied to brain is challenging due to the skull presence that attenuates ultrasound, leading to heating effects in bone region. In this study, we simulate trans-cranial nonlinear ultrasound propagation considering the detailed structure of bone tissue. We developed a 2D Finite Element (FE) model that mimics the propagation of focused ultrasound through skin, skull and brain tissue. The skull is represented as a three-layered system with two cortical tables packing a layer of trabecular bone. We assume that the space between the concave transducer and tissue is filled by water. Nonlinear ultrasound propagation is determined through Westervelt equation. To control reflection, absorbing layers have been implemented on the boundaries of the domains. The solution of the pressure equation is subsequently coupled with Pennes bioheat equation to determine the temperature distribution in the tissue region. The acoustic pressure, acoustic intensity and temperature distribution are achieved from FE simulation. Highest values of acoustic pressure occur in the focal area and in the bone tissue region. Ablative temperatures, i.e. superior to 55 degrees C, are achieved in the target zone and at the cortical-trabecular interface. The thermal response in the focal region is in agreement with available literature and allows to validate the model effectiveness. The FE model offers new insights to predict secondary heating effects of ultrasound propagation in the skull region and to improve treatment planning.

A 2d-fem model of nonlinear ultrasound propagation in trans-cranial mrgfus technique / Bini, F; Pica, A; Marrale, M; Gagliardo, C; Marinozzi, F. - 38:(2023), pp. 74-89. (Intervento presentato al convegno 17th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) / 5th Conference on Imaging and Visualization tenutosi a Bonn, Germany) [10.1007/978-3-031-10015-4_7].

A 2d-fem model of nonlinear ultrasound propagation in trans-cranial mrgfus technique

Bini, F
Primo
;
Pica, A;Marinozzi, F
Ultimo
2023

Abstract

Magnetic Resonance guided Focused Ultrasound (MRgFUS) is a non-invasive technique based on the thermal ablation of a target using high intensity focused ultrasound. MRgFUS treatment applied to brain is challenging due to the skull presence that attenuates ultrasound, leading to heating effects in bone region. In this study, we simulate trans-cranial nonlinear ultrasound propagation considering the detailed structure of bone tissue. We developed a 2D Finite Element (FE) model that mimics the propagation of focused ultrasound through skin, skull and brain tissue. The skull is represented as a three-layered system with two cortical tables packing a layer of trabecular bone. We assume that the space between the concave transducer and tissue is filled by water. Nonlinear ultrasound propagation is determined through Westervelt equation. To control reflection, absorbing layers have been implemented on the boundaries of the domains. The solution of the pressure equation is subsequently coupled with Pennes bioheat equation to determine the temperature distribution in the tissue region. The acoustic pressure, acoustic intensity and temperature distribution are achieved from FE simulation. Highest values of acoustic pressure occur in the focal area and in the bone tissue region. Ablative temperatures, i.e. superior to 55 degrees C, are achieved in the target zone and at the cortical-trabecular interface. The thermal response in the focal region is in agreement with available literature and allows to validate the model effectiveness. The FE model offers new insights to predict secondary heating effects of ultrasound propagation in the skull region and to improve treatment planning.
2023
17th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) / 5th Conference on Imaging and Visualization
Nonlinear acoustics; High intensity focused ultrasound; Brain biomechanics; Bone tissue; FEM
04 Pubblicazione in atti di convegno::04b Atto di convegno in volume
A 2d-fem model of nonlinear ultrasound propagation in trans-cranial mrgfus technique / Bini, F; Pica, A; Marrale, M; Gagliardo, C; Marinozzi, F. - 38:(2023), pp. 74-89. (Intervento presentato al convegno 17th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) / 5th Conference on Imaging and Visualization tenutosi a Bonn, Germany) [10.1007/978-3-031-10015-4_7].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1659654
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