| Co-Investigator(Kenkyū-buntansha) |
SUGISHITA Morihiro Graduate School of Medicine, Professor, 大学院・医学系研究科, 教授 (10114513)
OGINO Takashi National Center of Neurology and Psychiatry, National Institute of Neuroscience, Research Chief, 神経研究所, 室長(研究職) (50185526)
INOUE Yusuke Institute of Medical Science, Lecturer, 医科学研究所, 講師 (40232566)
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| Research Abstract |
Primary goal of this study was to evaluate the accuracy of our simple method for semiquantitative analysis of cerebral metabolites and to evaluate the possibility of proton MRS for clinical MR studies for cerebral disorders. The 3D-chemical shift imaging (CSI) data were obtained by PRESS sequence (TR/TE=2000msec/30msec, data points=2048, spectral width=2500Hz, phase steps= 24×24, FOV=24 cm, 1NEX, slice thickness=20mm, and acquisition time=19.3minutes) and the data without water suppression were obtained subsequently by same PRESS sequence (TR/TE=2000msec/30msec, data points=2048, spectral width=2500Hz, phase steps= 8×8, FOV=24 cm, 1NEX, slice thickness=20mm, and acquisition time=2.01 minutes). The 3D-MRSI data without water suppression by short time acquisition were used for correction of inhomogeneous B0 and B1 fields. The spectral peak and the signal intensity of non-suppressed water were used for correcting the B0 and B1 fields, respectively. The phase correction was done automatically by using the chemical shift of the spectral peak of the water. By using non-suppressed water image for correction of B0- and B1-inhomogenity and of phase shift, it was possible to obtain highly accurate quantitative cerebral ^1H 3D-CSI of the normal volunteers and the patients with cerebral disorders. In order to apply these quantitative ^1H-CSI in clinical studies, however, further development in fast chemical shift imaging technique and in software for analysis of quantification of cerebral metabolites was expected. Especially correction for T1 values of metabolites was difficult because of longer imaging time and lower SNR due to longer TR and shorter flip angle, respectively.
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