1H MRSI AT 7T USING AN INTERLEAVED NARROW-BAND PRESS SEQUENCE

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。 在7 T下使用具有空间-频谱绝热重聚焦脉冲的交错窄带PRESS序列的1H MRSI 质子磁共振波谱成像（1H MRSI）是一种有用的技术， 体内代谢物水平，胆碱（Cho）、肌酸（Cr）和N-乙酰天冬氨酸 (NAA)是感兴趣的最突出的MRS可检测的脑生化物质。1H MRSI 在很高的领域，如7 T，提供了更高的信噪比和改善频谱的优势 分辨率然而，与高场系统相关的主要技术挑战，例如 增加的化学位移定位（CSL）误差以及B1和B 0不均匀性， 常规1H MRSI序列的性能。为了解决这些问题，我们开发了 a具有绝热空间-光谱的位置分辨光谱（PRESS）序列 在一个实施例中，可以使用SPSP重聚焦脉冲，以交错方式获取多个窄光谱带。 绝热SPSP脉冲在达到峰值之前可以被过驱动1.6倍 我们的7 T全身磁体的RF幅度限制，提供磁化曲线， 在我们的7 T头部线圈测量的40% B1变化上基本不变。此外，本发明还 由于发射频率针对每个频谱进行调整，因此CSL误差可以忽略不计 乐队在体内1H MRSI数据从正常志愿者的大脑中获得，使用 标准PRESS序列和具有绝热的交织窄带PRESS序列 重新聚焦脉冲。与传统的PRESS相比，这种新方法产生了 更高质量的光谱，从明显更大的感兴趣的区域，并实现了更高的整体 叶老

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. 1H MRSI at 7T using an interleaved narrow-band PRESS sequence with spatial-spectral adiabatic refocusing pulses Proton magnetic resonance spectroscopic imaging (1H MRSI) is a useful technique for measuring metabolite levels in vivo, with Choline (Cho), Creatine (Cr) and N-Acetyl-Aspartate (NAA) being the most prominent MRS-detectable brain biochemicals of interest. 1H MRSI at very high fields, such as 7T, offers the advantages of higher SNR and improved spectral resolution. However, major technical challenges associated with high-field systems, such as increased chemical shift localization (CSL) error as well as B1 and B0 inhomogeneity, degrade the performance of conventional 1H MRSI sequences. To address these problems, we have developed a Position Resolved Spectroscopy (PRESS) sequence with adiabatic spatial-spectral (SPSP) refocusing pulses, to acquire multiple narrow spectral bands in an interleaved fashion. The adiabatic SPSP pulses can be overdriven by a factor of 1.6 before reaching the peak RF amplitude limits for our 7T whole body magnet, providing magnetization profiles that are largely invariant over the 40% B1 variation measured for our 7T head coil. Additionally, there is negligible CSL error since the transmit frequency is adjusted for each spectral band. In vivo 1H MRSI data was obtained from the brain of a normal volunteer using a standard PRESS sequence and the interleaved narrow-band PRESS sequence with adiabatic refocusing pulses. In comparison with conventional PRESS, this new approach generated high quality spectra from an appreciably larger region of interest and achieved higher overall SNR.