A 3D finite element model to study the cavitation induced stresses on blood-vessel wall during the ultrasound-only phase of photo-mediated ultrasound therapy.
A 3D finite element model to study the cavitation induced stresses on blood-vessel wall during the ultrasound-only phase of photo-mediated ultrasound therapy.
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光介导超声治疗（PUT）是一种利用同步超声和激光在血管内产生增强空化的新技术。血管内增强的空化诱导生物效应，其可导致微血管的去除和局部血液灌注的减少。这些生物效应具有治疗眼睛中的新血管形成疾病的潜力，例如年龄相关性黄斑变性和糖尿病视网膜病变。目前，PUT处于临床前阶段，在体内兔眼模型上的各种PUT研究已显示成功去除微血管。与目前的临床治疗（如抗血管内皮生长因子治疗和光动力治疗）相反，PUT是完全无创和无颗粒的，并且与激光光凝治疗不同，它精确地去除微血管而不损伤周围组织。在PUT过程中由振荡气泡产生的应力是血管中诱导的生物效应的原因。在我们以前的工作中，在第一阶段的PUT由于超声和激光联合照射引起的应力进行了研究，使用二维模型。在这项工作中，在第三或最后一个阶段的PUT由于单独的超声波引起的应力进行了研究，使用三维有限元法为基础的数值模型。结果表明，当气泡从容器中心向容器壁移动时，周向应力和剪切应力增加，剪切应力从1.848 kPa增加到31.060 kPa，增加了16倍以上，相比之下，对于放置在10 µm容器内的2 µm气泡，应用超声频率1MHz，振幅130kPa。此外，当气泡被放置在较小尺寸的血管中时，应力降低，周向应力降低较大。剪切应力的变化更依赖于气泡与容器壁的距离，而周向应力的变化更依赖于气泡的振幅。此外，气泡形状改变为椭圆形，随着其移动靠近容器壁，在容器的轴向方向上具有更高的振荡幅度，并且气泡振荡幅度随着其被放置在较小尺寸的容器中而急剧减小。
Photo-mediated ultrasound therapy (PUT) is a novel technique utilizing synchronized ultrasound and laser to generate enhanced cavitation inside blood vessels. The enhanced cavitation inside blood vessels induces bio-effects, which can result in the removal of micro-vessels and the reduction in local blood perfusion. These bio-effects have the potential to treat neovascularization diseases in the eye, such as age-related macular degeneration and diabetic retinopathy. Currently, PUT is in the preclinical stage, and various PUT studies on in vivo rabbit eye models have shown successful removal of micro-vessels. PUT is completely non-invasive and particle-free as opposed to current clinical treatments such as anti-vascular endothelial growth factor therapy and photodynamic therapy, and it precisely removes micro-vessels without damaging the surrounding tissue, unlike laser photocoagulation therapy. The stresses produced by oscillating bubbles during PUT are responsible for the induced bio-effects in blood vessels. In our previous work, stresses induced during the first phase of PUT due to combined ultrasound and laser irradiation were studied using a 2D model. In this work, stresses induced during the third or last phase of PUT due to ultrasound alone were studied using a 3D finite element method-based numerical model. The results showed that the circumferential and shear stress increased as the bubble moves from the center of the vessel toward the vessel wall with more than a 16 times increase in shear stress from 1.848 to 31.060 kPa as compared to only a 4 times increase in circumferential stress from 211 to 906 kPa for a 2 µm bubble placed inside a 10 µm vessel on the application of 1 MHz ultrasound frequency and 130 kPa amplitude. In addition, the stresses decreased as the bubble was placed in smaller sized vessels with a larger decrease in circumferential stress. The changes in shear stress were found to be more dependent on the bubble–vessel wall distance, and the changes in circumferential stress were more dependent on the bubble oscillation amplitude. Moreover, the bubble shape changed to an ellipsoidal with a higher oscillation amplitude in the vessel’s axial direction as it was moved closer to the vessel wall, and the bubble oscillation amplitude decreased drastically as it was placed in vessels of a smaller size.
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影响因子：
19.7
作者：
Hynynen, K;McDannold, N;Jolesz, FA
通讯作者：
Jolesz, FA
影响因子：
--
作者：
Chen, Hong;Brayman, Andrew A.;Bailey, Michael R.;Matula, Thomas J.
通讯作者：
Matula, Thomas J.
DOI：
10.1016/j.ijsolstr.2007.04.005
发表时间：
2007-11-01
影响因子：
3.6
作者：
Gao, Farong;Hu, Yuantai;Hu, Hongping
通讯作者：
Hu, Hongping
影响因子：
4.6
作者：
Hu Z;Zhang H;Mordovanakis A;Paulus YM;Liu Q;Wang X;Yang X
通讯作者：
Yang X
DOI：
10.1073/pnas.102184999
发表时间：
2002-05-28
影响因子：
11.1
作者：
Hoger, JH;Ilyin, VI;Hoger, A
通讯作者：
Hoger, A