Computational NeuroSurgery (CNS) Lab & Macquarie Neurosurgery, Macquarie Medical School, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, Australia.
Department of Radiology, MR-Physics, Medical University of Graz, Graz, Austria.
Adv Neurobiol. 2024;36:413-428. doi: 10.1007/978-3-031-47606-8_21.
Arteriovenous malformations (AVMs) are cerebrovascular lesions consisting of a pathologic tangle of the vessels characterized by a core termed the nidus, which is the "nest" where the fistulous connections occur. AVMs can cause headache, stroke, and/or seizures. Their treatment can be challenging requiring surgery, endovascular embolization, and/or radiosurgery as well. AVMs' morphology varies greatly among patients, and there is still a lack of standardization of angioarchitectural parameters, which can be used as morphometric parameters as well as potential clinical biomarkers (e.g., related to prognosis).In search of new diagnostic and prognostic neuroimaging biomarkers of AVMs, computational fractal-based models have been proposed for describing and quantifying the angioarchitecture of the nidus. In fact, the fractal dimension (FD) can be used to quantify AVMs' branching pattern. Higher FD values are related to AVMs characterized by an increased number and tortuosity of the intranidal vessels or to an increasing angioarchitectural complexity as a whole. Moreover, FD has been investigated in relation to the outcome after Gamma Knife radiosurgery, and an inverse relationship between FD and AVM obliteration was found.Taken altogether, FD is able to quantify in a single and objective value what neuroradiologists describe in qualitative and/or semiquantitative way, thus confirming FD as a reliable morphometric neuroimaging biomarker of AVMs and as a potential surrogate imaging biomarker. Moreover, computational fractal-based techniques are under investigation for the automatic segmentation and extraction of the edges of the nidus in neuroimaging, which can be relevant for surgery and/or radiosurgery planning.
动静脉畸形（AVM）是一种脑血管病变，由病变的血管组成，其特征是有一个核心称为病灶，是发生瘘管连接的“巢”。AVM 可引起头痛、中风和/或癫痫。其治疗可能具有挑战性，需要手术、血管内栓塞和/或放射外科治疗。AVM 的形态在患者之间差异很大，血管构筑参数仍然缺乏标准化，这些参数既可以作为形态学参数，也可以作为潜在的临床生物标志物（例如，与预后相关）。为了寻找 AVM 的新的诊断和预后神经影像学生物标志物，已经提出了基于计算分形的模型来描述和量化病灶的血管构筑。事实上，分形维数（FD）可用于量化 AVM 的分支模式。较高的 FD 值与具有更多数量和迂曲的颅内血管的 AVM 相关，或者与整体血管构筑复杂性的增加相关。此外，FD 已被研究与伽玛刀放射外科治疗后的结果有关，发现 FD 与 AVM 闭塞之间存在反比关系。总的来说，FD 能够以单一和客观的值来量化神经放射科医生以定性和/或半定量方式描述的内容，从而证实 FD 是 AVM 的可靠形态学神经影像学生物标志物，也是一种潜在的替代成像生物标志物。此外，基于计算分形的技术正在神经影像学中自动分割和提取病灶边缘，这对于手术和/或放射外科规划可能很重要。
