MULTI-EXCITATION NON-CPMG WITH LOW FLIP ANGLES FOR HYPERPOLARIZED 13C MRS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 我们报告了一种新的磁共振波谱成像序列，利用非CPMG 1，2 FSE回波链与二次相位 调制重聚焦脉冲以催化纵向磁化的稳定性，同时保持横向磁化 磁化在回波链期间重新聚焦。其他可选相位调制方案（XY、MLEV）仅适用于 在重聚焦脉冲旋转角（章动）1的非常有限的范围内，接近1/4。非CPMG阶段方案 对于低至160 <$s的章动表现良好，并且通过适当设计宽带宽的RF脉冲，该技术可以 非常适合快速光谱成像。因为非CPMG允许我们即使在 初始相位变化的存在，我们可以用FSE读数执行多个低翻转角激励，而无需等待 纵向信号通过T1弛豫恢复，这是超极化核光谱成像的理想条件。在 本报告中，我们显示了初步的测试结果，多激励非CPMG与低翻转角（门洛）和它的一个 映射T2弛豫时间的潜在应用。在13 C富集体模上进行测试， 这些参数适用于未来的超极化13 C应用。 要了解卢卡斯中心正在进行的其他项目，请访问http://rsl.stanford.edu/ （卢卡斯年度报告和 ISMRM 2011摘要）

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We report a new MR spectroscopic imaging sequence that utilizes non-CPMG1,2 FSE echo trains with quadratic phase modulation of the refocusing pulses to catalyze the stability of longitudinal magnetization while keeping the transverse magnetization refocused during the echo train. Other alternative phase modulation schemes (XY, MLEV ) are useful only over a very restricted range, close to ¿, of the refocusing pulse rotation angle (nutation)1. The non-CPMG phase scheme performs well for nutations as low as 160¿ and with a proper design of RF pulses of wide bandwidth, this technique can be quite suitable for fast spectroscopic imaging. Because non-CPMG allows us to obtain a full magnitude signal even in the presence of initial phase variation, we can perform multiple low flip-angle excitations with FSE readouts without waiting for the longitudinal signal to recover via T1 relaxation, a condition ideal for spectroscopic imaging of hyperpolarized nuclei. In this report, we show preliminary test results of multi-excitation non-CPMG with low flip angles (MENLO) and one of its potential applications for mapping T2 relaxation time. The tests were performed on a 13C-enriched phantom, with imaging parameters suitable for future hyperpolarized 13C applications. To read about other projects ongoing at the Lucas Center, please visit http://rsl.stanford.edu/ (Lucas Annual Report and ISMRM 2011 Abstracts)