Artifact-Free Diffusion Mapping with Echo-Planar Imaging

使用回波平面成像进行无伪影扩散映射

• 批准号: 6809267
• 负责人: NAN-KUEI CHEN
• 金额: $ 8.65万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-07 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6809267
• 关键词: bioimaging /biomedical imaging; clinical biomedical equipment; clinical research; evaluation /testing; human middle age (35-64); human subject; image enhancement; magnetic resonance imaging; method development; phantom model; time resolved data; young adult human (21-34)

DESCRIPTION (provided by applicant): The overall objective of the proposed project is to develop, optimize and validate an artifact-free diffusion mapping protocol based on echo-planar imaging (EPI), to enable a fast and accurate quantitative diffusion mapping in clinical examinations. EPI based diffusion mapping is a powerful tool to assess the microstructure of the biological tissues, and is valuable in the clinical examinations and the detection of pathological changes in various diseases, such as the ischemic stroke, multiple sclerosis, and tumor. However, the accuracy of EPI based diffusion mapping is usually degraded by various EPI artifacts, such as the Nyquist artifact and geometric distortions due to the eddy current. In this proposal, we aim to further improve the state-of-the-art EPI artifact removal methods, and integrate them into a diffusion mapping protocol in such a way that the clinical scan time is not increased. This project has three specific aims. Firstly, we plan to design techniques to remove artifacts in diffusion-weighted EPI, based on the distortion correction and Nyquist artifact removal techniques we have previously developed. Secondly, we plan to integrate the developed artifact removal methods into a diffusion mapping protocol without increasing the clinical scan time. Specifically, the time-consuming procedure for characterizing the eddy current phase errors (which are subject independent) will be performed on a phantom. In the clinical scan sessions, only the subject dependent phase errors will be measured using a modified EPI sequence. The phase error information obtained from phantom and clinical scans will be combined for an effective artifact removal. Finally, we will evaluate the effectiveness of the developed diffusion mapping protocol on eight normal subjects at 3 Tesla. The levels of artifacts before and after correction will be quantified, and the stability of the correction methods over multiple scan sessions will also be evaluated. A successful outcome from this study will generate a robust and rigorously validated diffusion mapping protocol free from EPI artifacts.

描述（由申请人提供）： 该项目的总体目标是开发、优化和验证基于回波平面成像（EPI）的无伪影扩散映射协议，以在临床检查中实现快速、准确的定量扩散映射。基于EPI的扩散图是评估生物组织微观结构的有力工具，在缺血性中风、多发性硬化症和肿瘤等多种疾病的临床检查和病理变化检测中具有重要价值。然而，基于 EPI 的扩散映射的精度通常会因各种 EPI 伪影而降低，例如奈奎斯特伪影和涡流引起的几何失真。在本提案中，我们的目标是进一步改进最先进的 EPI 伪影去除方法，并将其集成到扩散映射协议中，从而不增加临床扫描时间。该项目有三个具体目标。首先，我们计划基于我们之前开发的失真校正和奈奎斯特伪影消除技术，设计消除扩散加权 EPI 中的伪影的技术。其次，我们计划将开发的伪影去除方法集成到扩散映射协议中，而不增加临床扫描时间。具体来说，用于表征涡流相位误差（与受试者无关）的耗时过程将在体模上执行。在临床扫描过程中，将使用修改后的 EPI 序列仅测量受试者相关的相位误差。从体模和临床扫描获得的相位误差信息将被结合起来以有效去除伪影。最后，我们将评估所开发的扩散映射协议在 3 特斯拉下对八名正常受试者的有效性。校正前后的伪影水平将被量化，并且校正方法在多次扫描过程中的稳定性也将被评估。这项研究的成功结果将产生一个强大且经过严格验证的扩散映射协议，没有 EPI 伪影。