Calcification was recently found to be present in the majority of cerebral aneurysms, though how calcification and the presence or absence of co-localized lipid pools affect failure properties is still unknown. The primary objective is to quantify the biomechanical effect of a macro-calcification with surrounding Near-Calcification Region (NCR) of varying mechanical properties on tissue failure behavior. We utilized a structurally informed finite element model to simulate pre-failure and failure behavior of a human cerebral tissue specimen modeled as a composite containing a macro-calcification and surrounding NCR, embedded in a fiber matrix composite. Data from multiple imaging modalities was combined to quantify the collagen organization and calcification geometry. An idealized parametric model utilizing the calibrated model was used to explore the impact of NCR properties on tissue failure. Compared to tissue without calcification, peak stress was reduced by 82% and 49% for low modulus (representing lipid pool) and high modulus (simulating increase in calcification size) of the NCR, respectively. Failure process strongly depended on NCR properties with lipid pools blunting the onset of complete failure. When the NCR was calcified, the sample was able to sustain larger overall stress, however the failure process was abrupt with nearly simultaneous failure of the loaded fibers. Failure of calcified vascular tissue is strongly influenced by the ultrastructure in the vicinity of the calcification. Computational modeling of failure in fibrous soft tissues can be used to understand how pathological changes impact the tissue failure process, with potentially important clinical implications.

中文翻译：

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宏观钙化对颅内动脉瘤壁组织破坏机制的影响

最近发现大多数脑动脉瘤中都存在钙化，但钙化和共定位脂质池的存在或不存在如何影响失败特性仍不清楚。主要目标是量化宏观钙化及其周围具有不同机械特性的近钙化区域 (NCR) 对组织失效行为的生物力学影响。我们利用结构信息有限元模型来模拟人类脑组织样本的失效前和失效行为，该样本被建模为包含宏观钙化和周围 NCR 的复合材料，嵌入纤维基质复合材料中。结合多种成像方式的数据来量化胶原组织和钙化几何形状。利用校准模型的理想化参数模型用于探索 NCR 特性对组织衰竭的影响。与没有钙化的组织相比，NCR 的低模量（代表脂质池）和高模量（模拟钙化尺寸的增加）的峰值应力分别降低了 82% 和 49%。失效过程强烈依赖于 NCR 特性，脂质池可抑制完全失效的发生。当 NCR 钙化时，样品能够承受较大的总应力，但失效过程是突然的，加载的纤维几乎同时失效。钙化血管组织的衰竭受到钙化附近超微结构的强烈影响。纤维软组织失效的计算模型可用于了解病理变化如何影响组织失效过程，具有潜在的重要临床意义。