Lopez-Kolkovsky Alfredo L, Mériaux Sebastien, Boumezbeur Fawzi
NeuroSpin, I2BM, Commissariat à l'Energie Atomique, Gif-sur-Yvette, France.
Magn Reson Med. 2016 Feb;75(2):503-14. doi: 10.1002/mrm.25602. Epub 2015 Mar 29.
To measure the T1 and T2 relaxation times of water, metabolites, and macromolecules in the rat brain in vivo at 17.2T and achieve absolute quantification of the neurochemical profile. Relaxation times were compared with values from the literature found at lower magnetic fields.
(1) H NMR spectra were measured using a LASER localization sequence. T1 - and T2 -weighted spectra were analyzed using LCModel with an original parameterization of the macromolecule baseline.
The T1 relaxation times of 20 metabolites and the T2 relaxation times of 16 singlets and J-coupled metabolites were measured. The mean T1 and T2 relaxation times for metabolites were 1721 ± 237 ms and 148 ± 53 ms, respectively. In addition, we measured the T1 and T2 relaxation times of 4 macromolecule resonance groups, their mean T1 and T2 relaxation times being 690 ± 100 ms and 37 ± 15 ms, respectively. Absolute quantification of 21 metabolites and 4 groups of macromolecule resonances was achieved with Cramer-Rao Lower Bounds below 5% for Cr, Gln, Glu, GPC, Ins, NAA, PCr, and Tau and below 25% for the remaining resonances.
Comparison of our relaxation times to previously published values suggests a small increase of T1 values and a clear decrease of T2 values between 11.7 and 17.2T.
在17.2T磁场下对大鼠脑内水、代谢物和大分子的T1和T2弛豫时间进行活体测量，并实现神经化学图谱的绝对定量。将弛豫时间与在较低磁场下文献报道的值进行比较。
使用激光定位序列测量（1）H NMR谱。使用LCModel对T1加权和T2加权谱进行分析，并对大分子基线进行原始参数化。
测量了20种代谢物的T1弛豫时间以及16种单峰和J耦合代谢物的T2弛豫时间。代谢物的平均T1和T2弛豫时间分别为1721±237 ms和148±53 ms。此外，我们测量了4个大分子共振组的T1和T2弛豫时间，其平均T1和T2弛豫时间分别为690±100 ms和37±15 ms。对于Cr、Gln、Glu、GPC、Ins、NAA、PCr和Tau，21种代谢物和4组大分子共振的绝对定量的克莱姆-拉奥下界低于5%，其余共振的该下界低于25%。
将我们的弛豫时间与先前发表的值进行比较表明，在11.7T和17.2T之间，T1值略有增加，T2值明显降低。
