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In vivo detection of serine in the human brain by proton magnetic resonance spectroscopy ( 1 H‐MRS) at 7 Tesla

2009; Wiley; Volume: 62; Issue: 4 Linguagem: Inglês

10.1002/mrm.22079

1522-2594

Changho Choi, Ivan Dimitrov, Deborah Douglas, Chenguang Zhao, Halima Hawesa, Subroto Ghose, Carol A. Tamminga,

Advanced MRI Techniques and Applications

Abstract A single‐voxel proton magnetic resonance spectroscopy ( 1 H‐MRS) filtering strategy for in vivo detection of serine (Ser) in human brain at 7T is proposed. Spectral difference of coupled resonances arising from different subecho times of triple refocusing at a constant total echo time (TE) was utilized to detect the Ser multiplet and cancel the overlapping creatine (Cr) 3.92‐ppm singlet via difference editing. Dependence of the Ser signal on subecho times was investigated using density‐matrix simulation incorporating the slice‐selective radio frequency (RF) pulses. The simulation indicated that the difference‐edited Ser CH 2 multiplet at ∼3.96 ppm is maximized with (TE 1 , TE 2 , TE 3 ) = (54, 78, 78) and (36, 152, 22) ms. The edited Ser peak amplitude was estimated, with both numerical and phantom analyses of the performance, as 83% with respect to 90° acquisition for a localized volume, ignoring relaxation effects. From the area ratio of the edited Ser and unedited Cr 3.03‐ppm peaks, assuming identical T 1 and T 2 between Ser and Cr, the Ser‐to‐Cr concentration ratio for the frontal cortex of healthy adults was estimated to be 0.8 ± 0.2 (mean ± SD; N = 6). Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.