Dapeng Liu;Jinyuan Zhou;Rong Xue;Zhentao Zuo;Jing An;J. J. Danny Wang
期刊论文
10.1002/mrm.24560
SCIE, SSCI, ISTP
Magnetic Resonance in Medicine
17
70#4
2013/10/
1070#1081
1070#1081
PurposeThis study aimed to quantitatively investigate two main magnetization transfer effects at low B-1: the nuclear Overhauser enhancement (NOE) and amide proton transfer in the human brain at 7 T.
MethodsThe magnetization transfer effects in the human brain were characterized using a four-pool proton model, which consisted of bulk water, macromolecules, an amide group of mobile proteins and peptides, and NOE-related protons resonating upfield. The pool sizes, exchange rates, and relaxation times of these proton pools were investigated quantitatively by fitting, and the net signals of amide proton transfer and NOE were simulated based on the fitted parameters.
ResultsThe results showed that the four-pool model fitted the experimental data quite well, and the NOE effects in human brain at 7 T had a broad spectrum distribution. The NOE effects peaked at a B-1 of approximate to 1-1.4 T and were significantly stronger in the white matter than in the gray matter, corresponding to a pool-size ratio approximate to 2:1. As the amide proton transfer effect was relatively small compared with the NOE effects, magnetization transfer asymmetry analysis yielded an NOE-dominated contrast in the healthy human brain in this range of B-1.
ConclusionThese findings are important to identify the source of NOE effects and to quantify amide proton transfer effects in human brain at 7 T. Magn Reson Med, 70:1070-1081, 2013.
magnetization transfer; nuclear Overhauser enhancement; amide proton transfer; ultra high field; chemical exchange saturation transfer
鉴别脑胶质瘤复发与放射性坏死的磁共振分子成像新方法研究