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題名 Effects of Frequency Drift on the Quantification of Gamma-Aminobutyric Acid Using MEGA-PRES
作者 蔡尚岳
Tsai, Shang-Yueh;Fang, Chun-Hao;Wu, Thai-Yu;Lin, Yi-Ru
貢獻者 應物所
日期 2016-04
上傳時間 30-May-2016 15:23:03 (UTC+8)
摘要 The MEGA-PRESS method is the most common method used to measure γ-aminobutyric acid (GABA) in the brain at 3T. It has been shown that the underestimation of the GABA signal due to B0 drift up to 1.22 Hz/min can be reduced by post-frequency alignment. In this study, we show that the underestimation of GABA can still occur even with post frequency alignment when the B0 drift is up to 3.93 Hz/min. The underestimation can be reduced by applying a frequency shift threshold. A total of 23 subjects were scanned twice to assess the short-term reproducibility, and 14 of them were scanned again after 2–8 weeks to evaluate the long-term reproducibility. A linear regression analysis of the quantified GABA versus the frequency shift showed a negative correlation (P < 0.01). Underestimation of the GABA signal was found. When a frequency shift threshold of 0.125 ppm (15.5 Hz or 1.79 Hz/min) was applied, the linear regression showed no statistically significant difference (P > 0.05). Therefore, a frequency shift threshold at 0.125 ppm (15.5 Hz) can be used to reduce underestimation during GABA quantification. For data with a B0 drift up to 3.93 Hz/min, the coefficients of variance of short-term and long-term reproducibility for the GABA quantification were less than 10% when the frequency threshold was applied.
關聯 Scientific Reports, Vol.6, pp.24564
資料類型 article
DOI http://dx.doi.org/10.1038/srep24564
dc.contributor 應物所
dc.creator (作者) 蔡尚岳zh_TW
dc.creator (作者) Tsai, Shang-Yueh;Fang, Chun-Hao;Wu, Thai-Yu;Lin, Yi-Ru
dc.date (日期) 2016-04
dc.date.accessioned 30-May-2016 15:23:03 (UTC+8)-
dc.date.available 30-May-2016 15:23:03 (UTC+8)-
dc.date.issued (上傳時間) 30-May-2016 15:23:03 (UTC+8)-
dc.identifier.uri (URI) http://nccur.lib.nccu.edu.tw/handle/140.119/96996-
dc.description.abstract (摘要) The MEGA-PRESS method is the most common method used to measure γ-aminobutyric acid (GABA) in the brain at 3T. It has been shown that the underestimation of the GABA signal due to B0 drift up to 1.22 Hz/min can be reduced by post-frequency alignment. In this study, we show that the underestimation of GABA can still occur even with post frequency alignment when the B0 drift is up to 3.93 Hz/min. The underestimation can be reduced by applying a frequency shift threshold. A total of 23 subjects were scanned twice to assess the short-term reproducibility, and 14 of them were scanned again after 2–8 weeks to evaluate the long-term reproducibility. A linear regression analysis of the quantified GABA versus the frequency shift showed a negative correlation (P < 0.01). Underestimation of the GABA signal was found. When a frequency shift threshold of 0.125 ppm (15.5 Hz or 1.79 Hz/min) was applied, the linear regression showed no statistically significant difference (P > 0.05). Therefore, a frequency shift threshold at 0.125 ppm (15.5 Hz) can be used to reduce underestimation during GABA quantification. For data with a B0 drift up to 3.93 Hz/min, the coefficients of variance of short-term and long-term reproducibility for the GABA quantification were less than 10% when the frequency threshold was applied.
dc.format.extent 1272795 bytes-
dc.format.mimetype application/pdf-
dc.relation (關聯) Scientific Reports, Vol.6, pp.24564
dc.title (題名) Effects of Frequency Drift on the Quantification of Gamma-Aminobutyric Acid Using MEGA-PRES
dc.type (資料類型) article
dc.identifier.doi (DOI) 10.1038/srep24564
dc.doi.uri (DOI) http://dx.doi.org/10.1038/srep24564