High Resolution DTI Using 3D Single-Shot Acquisition

描述（由申请人提供）：弥散张量成像（DTI）提供了中枢和外周神经系统中白色物质束组织的相关信息。DTI已成功应用于脑纤维束成像，并对白色病变的早期诊断具有潜在的应用价值。在多发性硬化症等疾病中，弥散张量的早期变化可能先于常规MRI扫描可见的白色物质变化。然而，在目前的DTI技术的局限性，阻止了它在大脑和脊髓，视神经和周围神经，其中MS的早期变化可能是明显的使用。扩散张量成像需要长时间的数据采集，因此容易受到场不均匀性和患者运动引起的图像伪影的影响。这些伪影随着成像速度的加快而减少。单次激发扩散张量成像方法已经被开发为以更快的速度成像，从而以图像分辨率为代价减少运动和不均匀伪影。已经开发了多次激发方法以获得更高的分辨率，但是这些方法受到由多次采集之间的相位不一致引起的伪影的影响。我们已经开发了一种新的DTI技术，三维单次激发扩散加权成像与刺激回波采集（3D SS-DWSTEPI），获得扩散信息，在一个单一的拍摄采集在有限的成像体积。据我们所知，这是第一个关于三维体积的单射获取的报告。这项技术有可能克服目前使用的DTI技术的局限性。与二维成像相比，三维成像可以提供改善的SNR并且在切片边界处没有信号损失。使用容积选择性激发来创建交错的三维子容积将允许具有最佳回波链长度的更快成像。在该项目中，提出了实时导航来监测任何可能降低DTI测量精度的过度运动相关误差，并拒绝/重新获取特定数据。所提出的技术有可能使DTI的重要领域，如脊髓，周围神经，视神经，和目前的DTI方法目前无法访问的大脑区域，允许早期诊断白色物质疾病，如多发性硬化症。

DESCRIPTION (provided by applicant): Diffusion tensor imaging (DTI) provides information about the organization of white matter tracts in the central and peripheral nervous systems. DTI has been successfully applied to tractography of the brain, and has potential usefulness in early diagnosis of white matter disorders. Early changes in diffusion tensors may precede white matter changes visible on conventional MRI scans in diseases such as multiple sclerosis. However, limitations in current DTI techniques have prevented its use in much of the brain and in the spinal cord, optic nerves, and peripheral nerves, where early changes of MS may be manifest. Diffusion tensor imaging requires long data acquisitions and is therefore susceptible to image artifacts arising from field inhomogeneity and patient motion. These artifacts are reduced with faster imaging. Single- shot diffusion tensor imaging methods have been developed to image with greater speed, thus reducing motion and inhomogeneity artifacts, at the cost of image resolution. Multi-shot methods have been developed to attain higher resolution, but these methods are subject to artifacts caused by phase inconsistencies between multiple acquisitions. We have developed a novel DTI technique, three-dimensional single shot diffusion weighted imaging with stimulated echo acquisition (3D ss-DWSTEPI) which obtains diffusion information in a single shot acquisition over a limited imaging volume. To our knowledge, this is the first report on singleshot acquisition of three dimensional volume. This technique has the potential to overcome limitations of currently used DTI techniques. Three-dimensional imaging can give improved SNR and no loss of signal at the slice boundary in comparison with two-dimensional imaging. The use of volume-selective excitation to create interleaved three-dimensional subvolumes will allow faster imaging with optimal echo train lengths. In this project, realtime navigation is proposed to monitor any excessive motion related error which may reduce DTI measurement accuracy, and reject/reacquire the specific data. The proposed technique has the potential to make DTI possible in important areas such as the spinal cord, peripheral nerves, optic nerves, and regions of the brain not currently accessible by current DTI methods, allowing earlier diagnosis of white matter diseases such as multiple sclerosis.