在体检测γ-氨基丁酸的MEGA-PRESS序列优化设计

Optimization of the MEGA-PRESS Sequence for Detection of γ-Aminobutyric Acid in Vivo

γ-氨基丁酸(γ-aminobutyric acid,GABA)含量异常会引发一系列大脑疾病,因此在体检测人脑GABA含量成为一种十分必要的医疗技术.本文基于GABA检测常用的谱编辑方法 MEGA-PRESS,引入性能更好的SLR脉冲代替常用的高斯脉冲,并使用单频带和双频带结合的方法激发特定频率的物质,在联影(United Imaging Healthcare,UIH)的uMR780磁共振系统上实现了一种优化的MEGA-PRESS序列.结果表明:SLR脉冲可以减少大分子(macromolecule,MM)信号对GABA信号的干扰;单频带和双频带结合可以更好地抑制残余水信号对GABA~*信号的影响.水模实验和人体实验结果均证实优化的MEGA-PRESS序列可以更好地实现GABA~*含量在体检测.

Abnormal metabolism γ -aminobutyric acid （GABA） is involved in many brain diseases, and in vivo GABAdetection is important for the diagnosis of these diseases. This study optimized a commonly used spectral editing methodfor in vivo GABA detection, MEGA-PRESS. We used high-performance Shinnar-Le Roux （SLR） pulses to replace thecommonly used Gaussian pulses. Single-band pulse and dual-band pulse were combined to excite the resonances of givenmetabolites. An optimized MEGA-PRESS sequence was implemented on the uMR780 magnetic resonance imaging systemmanufactured by United Imaging Healthcare （UIH）. The results showed that the SLR pulse could reduce the interference ofmacromolecule （MM） on GABA signal. Compared with the traditional methods, combining the single-band and dual-bandpulses could better suppress contamination of residual water signal to the GABA＊ signal. Volunteer experimentsdemonstrated that the optimized MEGA-PRESS sequence improved in vivo measurement of GABA＊ concentration.