title: 1H NMR spectroscopic imaging of the mouse brain at 9.4 T.
abstract: OBJECTIVE
  To assess the feasibility of 1H spectroscopic imaging (SI) in the mouse brain at 9.4 T, and investigate regional variations in brain metabolites.
  
  
  METHODS
  A total of 21 SI studies were performed in CD-1 mice to evaluate the basal ganglia (N=5), hippocampus and thalamus (N=11), and cerebellum (N=5). We adjusted the B0 homogeneity for each slice using a fully automated shim calculation method based on the B0 map, which we measured using a multislice gradient-echo sequence with multiple phase evolution delays. The SI employed a modified localization by adiabatic selective refocusing (LASER) sequence with TE/TR of 50/2000 msec, 24x24 encodes over a field of view (FOV) of 24 mmx24 mm, 1 microL voxel resolution, and two averages, for a total acquisition time of 38 minutes.
  
  
  RESULTS
  Sufficient shimming was achieved and high-quality spectra were consistently obtained in each slice. N-acetyl aspartate (NAA)/creatine (Cr) ratios in the basal ganglia and thalamus (0.86+/-0.07, and 0.87+/-0.07, respectively) were significantly higher than those in the hippocampus and cerebellum (0.76+/-0.03 and 0.67+/-0.07), which were also significantly different from each other.
  
  
  CONCLUSIONS
  1H SI of the mouse brain is highly reproducible and allows differences in regional metabolite ratios to be easily visualized.
authors.affiliation: Department of Radiology, Albert Einstein College of Medicine, Bronx, New York 10461, USA. n.miyasaka.gyne@tmd.ac.jp
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyasaka
authors.forename: Kan
authors.initials: K
authors.lastname: Takahashi
authors.forename: Hoby P
authors.initials: HP
authors.lastname: Hetherington
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005240:Feasibility Studies; D016018:Least-Squares Analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D051379:Mice
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine