title: In vivo detection of serine in the human brain by proton magnetic resonance spectroscopy (1H-MRS) at 7 Tesla.
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 approximately 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 degrees 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).
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA. changho.choi@utsouthwestern.edu
authors.forename: Changho
authors.initials: C
authors.lastname: Choi
authors.forename: Ivan
authors.initials: I
authors.lastname: Dimitrov
authors.forename: Deborah
authors.initials: D
authors.lastname: Douglas
authors.forename: Chenguang
authors.initials: C
authors.lastname: Zhao
authors.forename: Halima
authors.initials: H
authors.lastname: Hawesa
authors.forename: Subroto
authors.initials: S
authors.lastname: Ghose
authors.forename: Carol A
authors.initials: CA
authors.lastname: Tamminga
mesh_terms: D000328:Adult; D000465:Algorithms; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012694:Serine / Q000032:analysis*; D055815:Young Adult
chemical_list: D011522:Protons; D012694:Serine