全脑同时神经黑色素敏感与定量磁化率成像

Simultaneously Neuromelanin-sensitive Imaging and Quantitative Susceptibility Mapping in the Whole Brain

尽管具有磁化转移(Magnetization Transfer,MT)的三维梯度回波序列可以同时进行神经黑色素和定量磁化率成像,但MT预饱和脉冲耗时长,且MT对磁化率定量的影响尚不明确.本文通过开发具有可变持续时间的MT脉冲,缩短了MT脉冲持续时间,并评估了MT对磁化率值定量的影响.研究结果显示,MT脉冲持续时间为5ms的梯度回波序列在显示神经黑色素方面不低于持续时间为8ms、10ms和12ms时序列的显示效果,并且得到的大脑深部灰质核团磁化率值与未加MT的序列具有良好一致性.这表明短持续时间的MT脉冲提供了一种同时成像神经黑色素和磁化率的实用方法.

Three-dimensional(3D)gradient recalled echo(GRE)sequence with magnetization transfer(MT)can simultaneously image neuromelanin and magnetic susceptibility.However,the sequence requires long duration of MT saturation pulse and the effect of MT pulse on susceptibility values remains unclear.Therefore,this paper aims to shorten the MT pulse duration and evaluate the effect of MT pulse on susceptibility value.Results showed that 3D GRE sequence with 5 ms of MT pulse provided a saturation effect no less than that of 8 ms,10 ms and 12 ms in highlighting neuromelanin,and yielded susceptibility values in the deep gray matter nuclei similar to sequence without MT pulse.In conclusion,short MT pulse provides a practical means to simultaneously image the neuromelanin and magnetic susceptibility.