FAST 1H MISSING-PULSE SSFP CHEMICAL SHIFT IMAGING OF THE HUMAN BRAIN AT 7 TESLA

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 最近，已经引入了稳态自由旋进（SSFP）化学位移成像技术，其由于其短测量时间（Tacq）和高灵敏度（SNR/SNR）而特别有吸引力。Tacq）。基于SSFP的方法的主要缺点是T1和T2对信号强度的影响使定量复杂化，并且由于TR短，光谱分辨率有限。而前者是一个固有的问题，后者是较少的问题，在高场强，如7 T，由于增加的分散的化学位移。光谱丢失脉冲SSFP（spMP-SSFP）具有可以获得全回波的优点。这允许在幅度模式下分析数据，而不会使谱线变宽。因此，这项工作的目的是实现spMP-SSFP与频谱空间射频脉冲在7 T的联合水和脂质抑制。 相对于低场和中场系统，更高的场强提供更好的信号分离和更高的SNR。即使当前可用的RF线圈使用相对较小的翻转角（45 <$），B1不均匀性也会对数据质量产生重大影响。更好的线圈设计和并行射频传输技术应有助于减少B1不均匀性引起的伪影。 资金来源 " NIH赠款RR 09784、AA 12388、AA 13521。 相关出版物 " D.迈耶，D. M.斯皮尔曼 7特斯拉下人脑1H快速失脉冲SSFP化学位移成像，Proc ISMRM，15 th Annual Meeting，柏林，2007，771.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Recently, steady state free precession (SSFP) chemical shift imaging techniques have been introduced which are particularly attractive because of their short measurement time (Tacq) and high sensitivity (SNR/Tacq). The main disadvantages of SSFP-based methods are that the effects of both T1 and T2 on the signal intensities complicate quantitation and the spectral resolution is limited due to the short TRs. Whereas the former is an inherent problem, the latter is less problematic at high field strengths such as 7 T due to the increased dispersion of the chemical shift. Spectroscopic missing pulse SSFP (spMP-SSFP) has the advantage that the full echo can be acquired. This allows data to be analyzed in magnitude mode without spectral line broadening. Therefore, the aim of this work was to implement spMP-SSFP with a spectral-spatial radiofrequency pulse for combined water and lipid suppression at 7 T. The higher field strength provides better signal separation and higher SNR relative to low- and midfield systems. Even when using a relatively small flip angle (45¿) with the currently available RF coil, B1 inhomogeneity has a substantial impact on data quality. Better coil designs and parallel RF transmission techniques should help to reduce the artifacts caused by B1 inhomogeneity. Funding Sources " NIH grants RR09784, AA12388, AA13521. Relevant publications " D. Mayer, D. M. Spielman Fast 1H Missing-Pulse SSFP Chemical Shift Imaging of the Human Brain at 7 Tesla, Proc ISMRM, 15th Annual Meeting, Berlin, 2007, 771.