Hemodynamic neuroimaging of pediatric stroke

小儿卒中的血流动力学神经影像学

• 批准号: 6911187
• 负责人: Danny JJ WANG
• 金额: $ 16.55万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6911187
• 关键词: adolescence (12-20); bioimaging /biomedical imaging; blood flow measurement; cerebrovascular imaging /visualization; child (0-11); clinical research; diagnosis design /evaluation; diffusion magnetic resonance imaging; hemodynamics; human subject; magnetic resonance imaging; noninvasive diagnosis; patient oriented research; prognosis; stroke

DESCRIPTION (provided by applicant): The goal of stroke treatment is to limit infarct size, improve outcome and prevent recurrence. A consensus is emerging from studies of adult stroke that multimodal MRI may play an important role in determining the volume of tissue that is at risk. Particularly, patients with regions of hypoperfusion larger than the volume of tissue with low diffusion are more likely to experience substantial enlargement of the infarct volume over time, a selection criteria for thrombolytic therapy in acute stroke. The mechanisms and outcome of pediatric stroke, however, are very poorly understood with no accepted protocol for patient treatment and management. The difficulty resides in the diverse etiology and clinical manifestations of pediatric stroke as well as the lack of suitable evaluation technology. Existing cerebral blood flow (CBF) measurements in adults cannot be easily applied on children due to safety concerns related to the use of radioisotopes and the logistical difficulties in rapidly injecting contrast agents in pediatric patients. Arterial spin labeling (ASL) perfusion MRI is a promising technology to directly measure CBF by utilizing magnetically labeled arterial blood water as endogenous tracer. This technique is ideally suited for pediatric imaging because it is totally noninvasive and provides improved image quality due to increased blood flow and water content of the pediatric brain. During recent years, we have developed and validated a suite of ASL methods to assess the hemodynamic status in cerebrovascular disease based on measurements of CBF and arterial transit time. Capitalizing on the latest advancement at high magnetic field, the image quality of these ASL methods has been greatly improved and approaching regular structural MRI scans. Building on the extensive experience in the development and application of ASL perfusion MRI at the University of Pennsylvania and the rich clinical resources at the Children's Hospital of Philadelphia, this proposed project will use the latest high field ASL methods to assess the hemodynamic status in pediatric stroke patients, aiming to probe the brain tissue at risk and predict the potential neurological outcome. In three specific aims, we will measure regional CBF, arterial transit time using ASL techniques along with diffusion imaging in pediatric stroke patients. We will then compare the deficit volumes detected in perfusion, diffusion and transit time modalities with the eventual infarct volume probed by follow up T2 lesion. The predicted outcome is that the volume of perfusion deficits detected in ASL images will be best correlated with T2 lesion volume. The obtained results are expected to enrich the understanding of the mechanism and development of pediatric stroke, as well as contribute to a standard for patient evaluation and treatment. The optimized pediatric ASL technique has potentially wide applicability in childhood brain disorders including sickle cell disease, neoplasm, peri ventricular leukomalacia etc. This project is therefore expected to advance the general application of ASL in the diagnosis, prognosis and management of pediatric brain disorders.

描述（由申请人提供）：中风治疗的目的是限制梗死大小，改善预后并防止复发。从成人中风的研究中得出了共识，即多模式MRI可能在确定处于危险中的组织量中起重要作用。特别是，灌注不足的区域大于扩散量低的组织的患者更有可能随着时间的推移经历梗死体积的大量扩大，这是急性中风中溶栓治疗的选择标准。然而，小儿中风的机制和结果对没有接受的患者治疗和管理方案的理解很糟糕。这些困难在于小儿中风的多种病因和临床表现以及缺乏合适的评估技术。由于与放射性同位素使用有关的安全问题以及在小儿患者迅速注入对比剂时的后勤困难，成人现有的脑血流（CBF）测量无法轻易应用于儿童。动脉自旋标记（ASL）灌注MRI是一项有前途的技术，可以通过利用磁标记的动脉血水作为内源性示踪剂来直接测量CBF。该技术非常适合小儿成像，因为它完全无创，并且由于小儿大脑的血流和水含量增加而提供了改善的图像质量。近年来，我们已经开发了一套ASL方法，以根据CBF和动脉运输时间的测量来评估脑血管疾病中的血液动力学状态。利用高磁场的最新进步，这些ASL方法的图像质量得到了极大的改进，并接近了常规的结构MRI扫描。在宾夕法尼亚大学的ASL灌注MRI开发和应用方面的广泛经验以及费城儿童医院的丰富临床资源的基础上，该提议的项目将使用最新的高现场ASL方法来评估儿科中风患者的血液动力学状态，以探究脑组织的风险和潜在的神经系统组织的可能性。在三个特定目标中，我们将使用ASL技术以及小儿中风患者的扩散成像来测量区域CBF，动脉传输时间。然后，我们将比较灌注，扩散和过境时间模态中检测到的缺陷量与随访T2病变探测的最终梗塞体积。预测的结果是，在ASL图像中检测到的灌注缺陷的体积将与T2病变体积相关。预期获得的结果将丰富对小儿中风的机制和发展的理解，并为患者评估和治疗的标准做出贡献。因此，优化的小儿ASL技术在儿童脑疾病中具有广泛的适用性，包括镰状细胞病，肿瘤，室室性白细胞乳突等。