基于分子间多量子相干的三维磁共振成像模拟

Simulation of Intermolecular Multiple-quantum Coherences in 3D Magnetic Resonance Imaging

核磁共振中的分子间多量子相干信号源自远程偶极相互作用.基于分子间多量子相干的成像信号能提供一种新的对比度机理.为了快速、高效地模拟和研究该对比度机理,本文运用如下算法:先对磁共振信号在实空间进行傅立叶变换,从而将磁化量从实空间变换至k空间,计算远程偶极场和扩散效应,然后将其变换回实空间来处理化学位移和弛豫等参数.研究结果表明:此算法可以准确反映三维结构样品中的偶极场效应,并且验证了由此产生的分子间多量子相干信号能够有效地提高磁共振成像的对比度.

In three-dimensional magnetic resonance imaging,intermolecular multiple-quantum coherences （iMQC） come from distant-dipole field effects. In this paper,a fast,efficient numerical algorithm was employed to simulate dipolar field effects for heterogeneous three dimensional structures. When suitable imaging parameters were selected, images with unique contrast were obtained without using contrast agents. Simulated results demonstrated that the iMQC images have contrast fundamentally different from the conventional single-quantum coherence images.