Comparison of longitudinal metabolite relaxation times in different regions of the human brain at 1.5 and 3 Tesla.
In vivo longitudinal relaxation times of N-acetyl compounds (NA), choline-containing substances (Cho), creatine (Cr), myo-inositol (mI), and tissue water were measured at 1.5 and 3 T using a point-resolved spectroscopy (PRESS) sequence with short echo time (TE). T(1) values were determined in six different brain regions: the occipital gray matter (GM), occipital white matter (WM), motor cortex, frontoparietal WM, thalamus, and cerebellum. The T(1) relaxation times of water protons were 26-38% longer at 3 T than at 1.5 T. Significantly longer metabolite T(1) values at 3 T (11-36%) were found for NA, Cho, and Cr in the motor cortex, frontoparietal WM, and thalamus. The amounts of GM, WM, and cerebrospinal fluid (CSF) within the voxel were determined by segmentation of a 3D image data set. No influence of tissue composition on metabolite T(1) values was found, while the longitudinal relaxation times of water protons were strongly correlated with the relative GM content.
Ethofer
Thomas
T
Section of Experimental MR of the CNS, Department of Neuroradiology, University of Tuebingen, Tuebingen, Germany.
Mader
Irina
I
Seeger
Uwe
U
Helms
Gunther
G
Erb
Michael
M
Grodd
Wolfgang
W
Ludolph
Albert
A
Klose
Uwe
U
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D001923:Brain Chemistry; D002531:Cerebellum / Q000737:chemistry; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D005260:Female; D005625:Frontal Lobe / Q000737:chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009044:Motor Cortex / Q000737:chemistry; D009778:Occipital Lobe / Q000737:chemistry; D010296:Parietal Lobe / Q000737:chemistry; D013788:Thalamus / Q000737:chemistry
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline