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

描述（由申请人提供）：脑动脉瘤是脑动脉的囊状扩张。如果不及时治疗，有些可能会破裂，造成死亡或损伤。血管内盘绕术是一种近年来日益流行的治疗方法。导管进入动脉瘤囊并填充线圈，这会在动脉瘤内形成血栓。线圈-凝块将阻止血液进入，从而保护动脉瘤免于破裂和出血。但在一些患者中，在手术后的几个月到几年里，血液会重新进入囊内，这种并发症被称为复发。10-30%接受线圈治疗的患者可出现复发。复发的原因尚不清楚。了解导致复发的原因很重要，因为这是应对这一挑战和减少其发病率的第一步。它也将显著影响动脉瘤患者的干预策略。该项目的总体目标是阐明复发的潜在机制。传统的观点认为，复发的发生是因为随着时间的推移，囊内的线圈团自身压缩（即体积减小），为血液重新进入提供了空间。这似乎是可信的，但采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情况并非如此。本研究的主要假设是，复发的机制是动脉瘤囊本身的生长，而不一定是线圈压实。该项目的第1个具体目标是在25例出现复发的线圈栓塞动脉瘤患者的统计数据中验证该假设。三维图像处理和计算分析工具将用于准确重建和估计旋转血管造影扫描的动脉瘤囊和线圈质量体积，以评估复发患者是否存在囊生长。此外，确定一些可测量的数据将是非常有益的

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.