Aneurysm Sac Growth as the Etiology of Recurrence in Coiled Cerebral Aneurysms

描述(申请人提供)：脑动脉瘤是大脑中动脉的囊状扩张。如果不治疗，有些可能会破裂，导致死亡或损伤。血管内卷曲是一种新的日益流行的治疗方法。在这里，通过导管进入动脉瘤囊并填充弹簧圈，这将在动脉瘤内诱导凝块的形成。线圈-凝块将不允许血液进入，从而保护动脉瘤免受破裂和出血。但在一些患者中，在手术后几个月到几年内，血液会重新进入囊内，这是一种称为复发的并发症。接受弹簧圈治疗的患者中有10%-30%可能复发。复发的原因人们知之甚少。重要的是要了解导致复发的原因，因为这是应对这一挑战并减少其发生率的第一步。这也将对动脉瘤患者的干预策略产生重大影响。这个项目的总体目标是阐明复发的潜在机制。传统的观点认为，复发的发生是因为线圈质量随着时间的推移在囊内自我压缩(即缩小)，为血液重新进入它腾出空间。尽管这看起来似乎是可信的，但通过使用严格的三维图像分析技术对试点人群进行的初步研究表明并非如此。这项研究的主要假设是，复发的机制是动脉瘤囊本身的生长，而不一定是弹簧圈致密。该项目的具体目标#1是在25名表现为复发的弹簧圈栓塞的动脉瘤患者中检验这一假设。三维图像处理和计算分析工具将用于从旋转血管造影扫描中准确重建和估计动脉瘤囊和线圈质量体积，以评估复发受试者是否存在动脉瘤囊生长。此外，如果确定一些可测量的 动脉瘤的形态指标或治疗方法可能是复发的危险因素。申请者小组开发了计算形态计量学工具，用于严格量化患者特定动脉瘤的三维形态，将其分为大小和形状指标。具体目标#2是比较AIM#1中易复发人群与大小和位置匹配的对照人群(即无复发的螺旋动脉瘤)之间的形态和操作指标。目标是确定哪些患者特有的可测量指标可以作为复发的预后指标。确定复发的危险因素可能有助于识别和避免患者容易出现这种主要并发症，否则是安全和有效的手术。如果AIM#1中的结果与提出的复发与囊腔生长相关的假设一致，则不断增长的动脉瘤患者不适合进行这一手术。因此，拟议的项目可以显著影响动脉瘤患者的临床管理。

DESCRIPTION (provided by applicant): Cerebral aneurysms are sac-like expansions of arteries in the brain. If left untreated, some may rupture causing death or impairment. Endovascular coiling is a recent and increasingly popular method of treatment. Here the aneurysm sac is accessed by a catheter and filled with coils, which should induce formation of a clot inside the aneurysm. The coil-clot mass will disallow entry of blood and hence protect the aneurysm from rupture and bleeding. But in some patients, within months to years of the procedure, blood is noted to re-enter the sac, a complication called recurrence. Recurrence can occur in 10-30% of patients treated with coils. The causes of recurrence are poorly understood. It is important to understand what causes recurrence because that is the first step in addressing this challenge and reducing its incidence. It will also significantly impact intervention strategie for aneurysm patients. The overall goal of this project is to shed light on the mechanisms underlying recurrence. Conventional thinking holds that recurrence occurs because the coil mass compacts itself (i.e., reduces in size) inside the sac over time, making room for blood to re-enter it. Plausible as this may seem, preliminary studies performed by employing rigorous three-dimensional image analysis techniques with a pilot population suggest otherwise. The primary hypothesis of this study is that the mechanism for recurrence is the growth of the aneurysm sac itself, not necessarily coil compaction Specific aim #1 of the project is to test the hypothesis in a statistically powered population of 25 coil-embolized aneurysm patients presenting with recurrence. Three dimensional image processing and computational analysis tools will be leveraged for accurate reconstructions and estimations of the aneurysm sac and coil mass volumes from rotational angiography scans in order to assess whether sac growth exists in recurrence subjects. Further, it would be quite beneficial to identify if some measurable metrics of aneurysm morphology or treatment procedure ay serve as risk factors for recurrence. The applicants' group has developed computational morphometric tools for rigorously quantifying the three-dimensional morphology of patient- specific aneurysms into size and shape metrics. Specific aim #2 is to compare metrics of morphology and procedure between the recurrence-prone population from aim #1 with a control population (i.e., coiled aneurysms that do not show recurrence) that is size and location-matched. The goal is to ascertain which, if any, of the patient-specific measurable metrics may serve as prognostic indicators of recurrence. Identifying risk factors of recurrence may help identify and avoid patients prone to this major complication from this otherwise safe and effective procedure. If the results in aim #1 are consistent with proposed hypothesis that recurrence is associated with sac growth, patients with growing aneurysms are not suitable candidates for this procedure. The proposed project therefore can significantly impact clinical management of aneurysm patients.