Xu Y, Balschi J A, Springer C S
Department of Chemistry, State University of New York, Stony Brook 11794-3400.
Magn Reson Med. 1990 Oct;16(1):80-90. doi: 10.1002/mrm.1910160109.
Paramagnetic compounds are often used to enhance contrast in MRI by virtue of their increase in the kinetics of the relaxation of water 1H magnetization. Here, we demonstrate a method for contrast enhancement which is based on the resonance frequency shifts caused by the bulk magnetic susceptibility (BMS) effects of such compounds. This involves the frequency selective excitation in the absence of field gradients, during the imaging sequence, of a portion of the water 1H resonance which is rendered inhomogeneous by BMS shifts only. The image which results is of that portion of the sample which gives rise to the portion of the spectrum excited. A phantom sample which simulates some aspects of tissue, particularly blood vessels with different orientations in the magnetic field, was prepared. The contrast enhancement exhibited here avoids some of the distortions attendant to the use of paramagnetic reagents. This new approach can, in principle, utilize the natural BMS differences found in all tissue.
顺磁性化合物常常因其加快水1H磁化弛豫动力学的能力而被用于增强磁共振成像（MRI）的对比度。在此，我们展示了一种基于此类化合物的体磁敏感性（BMS）效应所引起的共振频率偏移来增强对比度的方法。这涉及在成像序列中，在没有场梯度的情况下对仅因BMS偏移而变得不均匀的一部分水1H共振进行频率选择性激发。所得图像是样品中产生被激发光谱部分的那一部分的图像。制备了一个模拟组织某些方面的体模样品，特别是模拟了磁场中不同取向的血管。此处展示的对比度增强避免了使用顺磁性试剂时伴随的一些失真。原则上，这种新方法可以利用所有组织中存在的天然BMS差异。
