Division of Neuroimaging and Neurointervention, Stanford Initiative for Multimodality neuro-Imaging in Translational Anatomy Research (SIMITAR), Department of Radiology, Stanford University School of Medicine, Stanford, California, USA.
Clin Anat. 2021 Apr;34(3):326-332. doi: 10.1002/ca.23589. Epub 2020 Apr 3.
Blood vessel tortuosity results from increased diameter and length in response to higher hemodynamic loads. Tortuosity metrics have not been determined for abnormal superior cerebral veins (SCVs) draining cerebral arteriovenous malformations (AVMs). Draining vein (DV) tortuosity may influence safety and efficacy of retrograde microcatheter navigation during transvenous treatment of pial AVMs. Here, we quantify SCV tortuosity in normal subjects and AVM patients using two image segmentation methods. We used contrast-enhanced brain magnetic resonance (MR) images to define the axis of each SCV through a regularly spaced set of three-dimensional (3D) points defining its skeleton curve. We then calculated two metrics: the "sum of angles metric" (SOAM), which adds all angles of curvature along a vessel and normalizes by vessel length, and the "distance metric" (DM), a tortuosity measure providing a ratio of vessel length to linear distance between vessel endpoints. We analyzed 168 metrics in 43 veins of eight normal subjects and 41 veins of seven AVM patients. In normal subjects, the mean SOAM and DM for SCVs were 21.34 ± 7.49 °/mm and 1.42 ± 0.25, respectively. In AVM patients, DVs had a significantly higher mean SOAM of 30.43 ± 11.38 °/mm (p = .02) and DM of 2.79 ± 1.77 (p = .01) than normal subjects. In AVM patients, DVs were significantly more tortuous than matched contralateral uninvolved SCVs, which were similar in tortuosity to normal subject SCVs. We thus report normative tortuosity metrics of brain SCVs and show that AVM cortical DVs are significantly more tortuous than normal SCVs. Knowledge of these comparative tortuosities is valuable in planning endovenous AVM embolotherapies.
血管迂曲是由于直径和长度增加，以应对更高的血液动力学负荷所致。尚未确定异常大脑上静脉（SCV）引流脑动静脉畸形（AVM）的迂曲度测量标准。引流静脉（DV）的迂曲度可能会影响经静脉治疗脑 AVM 时逆行微导管导航的安全性和有效性。在此，我们使用两种图像分割方法来量化正常受试者和 AVM 患者的 SCV 迂曲度。我们使用对比增强脑磁共振（MR）图像，通过一组规则间隔的三维（3D）点定义每个 SCV 的轴，这些点定义了其骨架曲线。然后，我们计算了两个度量标准：“角度总和度量”（SOAM），该度量标准沿血管增加所有曲率角度，并通过血管长度进行归一化；以及“距离度量”（DM），这是一种迂曲度度量标准，提供了血管长度与血管端点之间的直线距离的比值。我们分析了 8 名正常受试者的 43 条静脉和 7 名 AVM 患者的 41 条静脉中的 168 个度量标准。在正常受试者中，SCV 的平均 SOAM 和 DM 分别为 21.34 ± 7.49°/mm 和 1.42 ± 0.25。在 AVM 患者中，DV 的平均 SOAM 明显更高，为 30.43 ± 11.38°/mm（p = 0.02），DM 也明显更高，为 2.79 ± 1.77（p = 0.01）。与正常受试者的 SCV 相比，AVM 患者的 DV 明显更迂曲，而与之相匹配的对侧未受累 SCV 的迂曲度与正常受试者的 SCV 相似。因此，我们报告了脑 SCV 的正常迂曲度度量标准，并表明 AVM 皮质 DV 比正常 SCV 明显更迂曲。了解这些比较迂曲度对于规划经静脉 AVM 栓塞治疗非常有价值。
