Chadzynski Grzegorz L, Pohmann Rolf, Shajan Gunamony, Kolb Rupert, Bisdas Sotirios, Klose Uwe, Scheffler Klaus
Biomedical Magnetic Resonance, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany,
MAGMA. 2015 Jun;28(3):239-49. doi: 10.1007/s10334-014-0460-5. Epub 2014 Sep 24.
In this study, the feasibility of in vivo proton magnetic resonance spectroscopic imaging ((1)H MRSI) of the healthy human brain at a field strength of 9.4 T, using conventional acquisition techniques, is examined and the initial experience is summarized.
MRSI measurements were performed on a 9.4 T MR scanner (Siemens, Erlangen, Germany) equipped with head-only gradient insert (AC84, Siemens) and custom-developed, 8-channel transmit/24-channel receive, and 16-channel transmit/31-channel receive coils. Spectra were acquired from the superior part of the human brain with a modified STEAM sequence. Spectral quantification was done with LCModel software.
Reasonable quality and signal-to-noise ratio of the acquired spectra allowed reliable quantification of 12 metabolites (Cramer-Rao lower bounds < 20 %), some of which may be difficult to quantify at field strengths below 7 T due to overlapping resonances or low concentrations.
While further developments are necessary to minimize chemical shift displacement and homogeneity of the transmit field, it is demonstrated that in vivo (1)H MRSI at a field strength of 9.4 T is possible. However, further studies applying up-to-date techniques to overcome high-field specific problems are needed in order to assess the potential gain in sensitivity that may be offered by MRSI at 9.4 T.
在本研究中，使用传统采集技术，对健康人脑在9.4 T场强下进行体内质子磁共振波谱成像（（1）H MRSI）的可行性进行了研究，并总结了初步经验。
在配备仅头部梯度插入件（AC84，西门子）以及定制开发的8通道发射/24通道接收和16通道发射/31通道接收线圈的9.4 T MR扫描仪（西门子，埃尔朗根，德国）上进行MRSI测量。使用改良的STEAM序列从人脑上部采集光谱。使用LCModel软件进行光谱定量。
所采集光谱具有合理的质量和信噪比，能够对12种代谢物进行可靠定量（克莱姆 - 拉奥下界<20%），其中一些代谢物由于共振重叠或浓度低，在低于7 T的场强下可能难以定量。
虽然需要进一步改进以最小化化学位移偏移和发射场的均匀性，但已证明在9.4 T场强下进行体内（1）H MRSI是可行的。然而，需要进一步开展应用最新技术来克服高场特定问题的研究，以便评估9.4 T的MRSI可能提供的灵敏度潜在增益。
