磁振頻譜能提供代謝物的訊息，但在腦中要收取到品質好的頻譜不容易，於是分別使用了三種技術來讓頻譜可以有更好的品質。隨著主磁場提高，會導致磁場不均勻性增加，利用最先進的Shim技術，其使用FASTMAP方法讓最後得到的頻譜頻寬能縮小。在頻譜中，水訊號都會高出代謝物幾千倍，造成代謝物無法輕易的看見，通常會使用水抑制技術來使水信號降低，所以使用VAPOR技術並且經過我們的最佳化將水訊號壓低，讓代謝物能夠容易辨識。最後採集資料使用sLASER序列，其能降低CSDE的問題並且在空間選擇性上有更好的優勢，在SNR的表現能夠和PRESS序列的結果相近。透過以上種技術能將頻譜的品質變好，並且利用後處理進行一系列的處理，可以讓後續代謝物定量評估變的更準確。

Magnetic resonance spectroscopy can provide information about metabolites, but it is difficult to obtain high-quality spectra in the brain. Therefore, three different techniques were used to improve the quality of the spectra. As the main magnetic field increases, the magnetic field inhomogeneity increases. The most advanced Shim technology was used to reduce the final spectrum bandwidth using the FASTMAP method. In the spectrum, the water signal is thousands of times higher than the metabolites, making it difficult to see the metabolites. Water suppression techniques are usually used to reduce the water signal. Therefore, the VAPOR technology was used to optimize the water signal and make the metabolites easier to identify. Finally, the sLASER sequence was used to collect data, which can reduce the problem of CSDE and has better advantages in spatial selectivity. The SNR performance can be similar to that of the PRESS sequence. Through these techniques, the quality of the spectra can be improved, and post-processing can be used to make subsequent metabolite quantification more accurate.

[1] H. Watanabe and N. Takaya, "Quantitation error in 1H MRS caused by B1 inhomogeneity and chemical shift displacement," Magnetic Resonance in Medical Sciences, vol. 17, no. 3, p. 244, 2018.
[2] G. Öz et al., "Advanced single voxel 1H magnetic resonance spectroscopy techniques in humans: Experts' consensus recommendations," NMR in Biomedicine, vol. 34, no. 5, p. e4236, 2021.
[3] M. Wilson et al., "A methodological consensus on clinical proton MR spectroscopy of the brain: review and recommendations," Magn. Reson. Med, 2020.
[4] A. A. Maudsley et al., "Advanced magnetic resonance spectroscopic neuroimaging: Experts' consensus recommendations," NMR in Biomedicine, vol. 34, no. 5, p. e4309, 2021.
[5] A. D'Astous et al., "Shimming toolbox: An open‐source software toolbox for B0 and B1 shimming in MRI," Magnetic Resonance in Medicine, vol. 89, no. 4, pp. 1401-1417, 2023.
[6] K. Landheer and C. Juchem, "FAMASITO: FASTMAP Shim Tool towards user‐friendly single‐step B0 homogenization," NMR in Biomedicine, vol. 34, no. 6, p. e4486, 2021.
[7] R. Gruetter and I. Tkáč, "Field mapping without reference scan using asymmetric echo‐planar techniques," Magnetic Resonance in Medicine: An Official Journal of the International Society for Magnetic Resonance in Medicine, vol. 43, no. 2, pp. 319-323, 2000.
[8] R. Kreis et al., "Terminology and concepts for the characterization of in vivo MR spectroscopy methods and MR spectra: Background and experts' consensus recommendations," NMR in biomedicine, vol. 34, no. 5, p. e4347, 2021.
[9] Z. Dong, "Proton MRS and MRSI of the brain without water suppression," Progress in nuclear magnetic resonance spectroscopy, vol. 86, pp. 65-79, 2015.
[10] I. Tkáč et al., "Water and lipid suppression techniques for advanced 1H MRS and MRSI of the human brain: experts' consensus recommendations," NMR in Biomedicine, vol. 34, no. 5, p. e4459, 2021.
[11] K. L. Chan, R. Ouwerkerk, and P. B. Barker, "Water suppression in the human brain with hypergeometric RF pulses for single‐voxel and multi‐voxel MR spectroscopy," Magnetic resonance in medicine, vol. 80, no. 4, pp. 1298-1306, 2018.
[12] T. W. Scheenen, D. W. Klomp, J. P. Wijnen, and A. Heerschap, "Short echo time 1H‐MRSI of the human brain at 3T with minimal chemical shift displacement errors using adiabatic refocusing pulses," Magnetic Resonance in Medicine: An Official Journal of the International Society for Magnetic Resonance in Medicine, vol. 59, no. 1, pp. 1-6, 2008.
[13] D. K. Deelchand, K. Kantarci, and G. Öz, "Improved localization, spectral quality, and repeatability with advanced MRS methodology in the clinical setting," Magnetic resonance in medicine, vol. 79, no. 3, pp. 1241-1250, 2018.
[14] J. P. Wijnen et al., "Short echo time 1H MRSI of the human brain at 3T with adiabatic slice‐selective refocusing pulses; reproducibility and variance in a dual center setting," Journal of Magnetic Resonance Imaging, vol. 31, no. 1, pp. 61-70, 2010.
[15] M. Garwood and L. DelaBarre, "The return of the frequency sweep: designing adiabatic pulses for contemporary NMR," Journal of magnetic resonance, vol. 153, no. 2, pp. 155-177, 2001.
[16] D. K. Deelchand et al., "Across‐vendor standardization of semi‐LASER for single‐voxel MRS at 3T," NMR in Biomedicine, vol. 34, no. 5, p. e4218, 2021.
[17] G. Öz and I. Tkáč, "Short-echo, single-shot, full-intensity 1H MRS for neurochemical profiling at 4T: validation in the cerebellum and brainstem," Magnetic resonance in medicine: official journal of the Society of Magnetic Resonance in Medicine/Society of Magnetic Resonance in Medicine, vol. 65, no. 4, 2011.
[18] V. Mlynárik, G. Gambarota, H. Frenkel, and R. Gruetter, "Localized short‐echo‐time proton MR spectroscopy with full signal‐intensity acquisition," Magnetic Resonance in Medicine: An Official Journal of the International Society for Magnetic Resonance in Medicine, vol. 56, no. 5, pp. 965-970, 2006.
[19] J. Near et al., "Preprocessing, analysis and quantification in single‐voxel magnetic resonance spectroscopy: experts' consensus recommendations," NMR in Biomedicine, vol. 34, no. 5, p. e4257, 2021.
[20] S. W. Provencher, "Automatic quantitation of localized in vivo 1H spectra with LCModel," NMR in Biomedicine: An International Journal Devoted to the Development and Application of Magnetic Resonance In Vivo, vol. 14, no. 4, pp. 260-264, 2001.