位於腦內壁的扣帶迴(cingulate cortex)在病理學領域已有相當廣泛的研究，內容擴及精神失調以及慢性疼痛。有許多癌症或神經損傷所造成的疼痛並無法單純用藥物治療，因此神經外科手術透過切除部分的扣帶迴來治療這些頑固性的疼痛。然而興奮性傳輸神經「谷氨酸鹽(Glutamate)」扮演相當重要的角色，不僅涉及病理學更是一種藥物干預的機制，而「麩醯胺(Glutamine)」為谷氨酸鹽的病理機制與藥物動態的前兆，透過定量谷氨酸鹽與麩醯胺的代謝物可提供相當重要的資訊。面迴訊氫原子核磁振頻譜影像(proton echo planar spectroscopic imaging; PEPSI) 技術是一種快速的磁共振頻譜影像(magnetic resonance spectroscopic imaging; MRSI)掃描方法，它可用來估算腦袋內代謝物的含量及種類。本實驗我們提出兩種掃描時間少於十分鐘的面迴訊氫原子核磁振頻譜影像序列協定來量測腦內壁的谷氨酸鹽及麩醯胺，由於在核磁振頻譜中谷氨酸鹽及麩醯胺屬於在同一個頻譜範圍內的代謝物，為了可以單獨量測到谷氨酸鹽，我們使用編輯頻譜的方式將回音時間(Time to Echo; TE)平均(TEavg)以達到減少麩醯胺以利突顯谷氨酸鹽的頻譜。最後透過重複性(reproducibility)的實驗定量短回音時間(short-TE)及平均回音時間(TE -averaged)下的谷氨酸鹽、麩醯胺及兩者之混和(Glx)之代謝物濃度。

Cingulate cortex (CC) is involved in many pathological conditions including psychiatric disorders and chronic pain. As the major excitatory neurotransmitter of the brain, glutamate (Glu) plays an important role not only in the pathology of these conditions but also as a mechanism for drug intervention. Glutamine (Gln) is the precursor of both Glu and Gamma-Amino Butyric acid (GABA), the major inhibitory neurotransmitter of the brain. Quantification of Glu and Gln in CC may provide important information about pathological mechanisms and drug dynamics. We used Proton Echo Planar Spectroscopic Imaging (PEPSI), a fast magnetic resonance spectroscopic imaging (MRSI) technique, sequence with short-TE (TE30) and averaged TE (TEavg) protocols to detect Glu and Gln in CC. Although a better fitting was obtained for Glu with TEavg, there was no obvious difference in coefficient of variance (COV) of Glu between two protocols. In conclusion, PEPSI is suitable for assessment of short-term and long-term changes in brain metabolites. Compared to TEavg, TE30 protocol had similar performance on Glu but provides more accurate quantification of Gln and other metabolites.

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