Localized short-echo-time proton MR spectroscopy with full signal-intensity acquisition
Localized short-echo-time proton MR spectroscopy with full signal-intensity acquisition
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DOI：
10.1002/mrm.21043
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发表时间：
2006-11-01
影响因子：
3.3
通讯作者：
Gruetter, Rolf
中科院分区：
文献类型：
--
作者：
Mlynarik, Vladimir;Gambarota, Giulio;Gruetter, Rolf
我们将一维加减方案与双片选择性自旋回波（SE）序列相结合，开发了质子局域光谱的短回波时间（TE）序列。该序列保留了所选感兴趣体积（VOI）的全部磁化强度。通过减少作用于横向磁化的射频（RF）脉冲的数量，我们能够将TE降至与受激回波采集模式（STEAM）技术相同的水平，同时灵敏度也提高了两倍。在加减定位中使用绝热脉冲，提高了在高磁场下经常遇到的空间非均匀射频场中的激发效率。该方法被称为自旋回声，全强度获得定位（SPECIAL）光谱，在大鼠大脑中进行了体内实验。与光谱成像相结合，实现了2 μ l的空间分辨率，信噪比（SNR）超过30，通常足以可靠地定量大量代谢物（神经化学谱）。
We developed a short-echo-time (TE) sequence for proton localized spectroscopy by combining a 1D add-subtract scheme with a doubly slice-selective spin-echo (SE) sequence. The sequence preserves the full magnetization available from the selected volume of interest (VOI). By reducing the number of radiofrequency (RF) pulses acting on transverse magnetization, we were able to minimize the TE to the level that is achievable with the stimulated echo acquisition mode (STEAM) technique, and also gained a twofold increase in sensitivity. The use of an adiabatic pulse in the add-subtract localization improved the efficiency of excitation in spatially inhomogeneous RF fields, which are frequently encountered at high magnetic fields. The localization performance and sensitivity gains of this method, which is termed SPin ECho, full Intensity Acquired Localized (SPECIAL) spectroscopy, were demonstrated in vivo in rat brains. In conjunction with spectroscopic imaging, a 2-mu l spatial resolution was accomplished with a signal-to-noise ratio (SNR) above 30, which is usually sufficient for reliable quantification of a large number of metabolites (neurochemical profile).