1H metabolite relaxation times at 3.0 tesla:: Measurements of T1 and T2 values in normal brain and determination of regional differences in transverse relaxation
1H metabolite relaxation times at 3.0 tesla:: Measurements of T1 and T2 values in normal brain and determination of regional differences in transverse relaxation
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DOI：
10.1002/jmri.20053
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发表时间：
2004-05-01
影响因子：
4.4
通讯作者：
Schild, HH
中科院分区：
文献类型：
--
作者：
Träber, F;Block, W;Schild, HH
目的：测定3t时脑代谢物H-1松弛时间，探讨脑内区域差异。材料与方法：在3.0 t临床全身磁共振（MR）系统上进行研究。测定42名健康受试者6个脑区n -乙酰天冬氨酸（NAA）、总肌酸（tCr）和胆碱化合物（Cho）的T2弛豫时间。测定10例受试者枕白质（WM）、额叶和运动皮层中这些代谢物和肌醇（Ins）的T1松弛时间。结果：在所有研究区域，所有代谢物的T2值相对于1.5 T显著降低。运动皮层NAA T2 （247 +/- 13 msec）明显短于枕部WM (301 +/- 18 msec) （P < 0.001）。tCr甲基共振T2显示相应但不太明显的降低（162 +/- 16 msec比178 +/- 9 msec， P = 0.021）。基底神经节中所有代谢物的T2值甚至更低。3.0 T时代谢物T1弛豫时间与1.5 T时无显著差异。结论：所研究的脑代谢物的横向弛豫时间与磁场强度成反比，特别是NAA的T2在3 T时表现出明显的区域差异，这可能归因于相对WM/灰质（GM）含量的差异和局部顺磁性。
Purpose: To measure H-1 relaxation times of cerebral metabolites at 3 T and to investigate regional variations within the brain.Materials and Methods: Investigations were performed on a 3.0-T clinical whole-body magnetic resonance (MR) system. T2 relaxation times of N-acetyl aspartate (NAA), total creatine (tCr), and choline compounds (Cho) were measured in six brain regions of 42 healthy subjects. T1 relaxation times of these metabolites and of myo-inositol (Ins) were determined in occipital white matter (WM), the frontal lobe, and the motor cortex of 10 subjects.Results: T2 values of all metabolites were markedly reduced with respect to 1.5 T in all investigated regions. T2 of NAA was significantly (P < 0.001) shorter in the motor cortex (247 +/- 13 msec) than in occipital WM (301 +/- 18 msec). T2 of the tCr methyl resonance showed a corresponding yet less pronounced decrease (162 +/- 16 msec vs. 178 +/- 9 msec, P = 0.021). Even lower T2 values for all metabolites were measured in the basal ganglia. Metabolite T1 relaxation times at 3.0 T were not significantly different from the values at 1.5 T.Conclusion: Transverse relaxation times of the investigated cerebral metabolites exhibit an inverse proportionality to magnetic field strength, and especially T2 of NAA shows distinct regional variations at 3 T. These can be attributed to differences in relative WM/gray matter (GM) contents and to local paramagnetism.