Department of Neurosurgery, JE Purkynje University and Masaryk Hospital, Usti nad Labem, Czech Republic.
Eur J Radiol. 2012 Aug;81(8):1877-82. doi: 10.1016/j.ejrad.2011.04.074. Epub 2011 Jun 12.
The aim of this study was to investigate in detail the effect of gadolinium contrast on diffusion tensor imaging scans. As the present literature offers conflicting results, we have included a large selection of indices in the analysis.
Sixteen patients harboring an intra-axial contrast enhancing brain tumor were included in this study. Two diffusion tensor imaging scans were performed-one natively, and the second following a gadolinium contrast agent application. Maps of the invariant indices fractional anisotropy (FA), linear, planar, and spherical indices, trace, eigenvalues λ(1), λ(2), λ(3) as well as of the components of the diffusion tensor matrix Dxx, Dyy, Dzz, Dxy, Dxz and Dyz were co-registered and compared statistically with matching ROI pairs in the contrast enhancing areas, peritumoral edema and the normal appearing white matter.
We have observed a significant increase in the FA and disproportional decrease of the eigenvalues in the post-contrast scans. In accordance with these findings, the spherical index was decreased and the linear and planar indices were increased. There was a significant decrease of all diagonal components of the diffusion tensor matrix. These changes have been strongest in the contrast enhancing areas, but there were also significant changes in the peritumoral edema and the normal appearing white matter.
Diffusion tensor imaging scans performed after gadolinium contrast agent administration may display artificially increased FA values due to disproportional changes of the measured eigenvalues. The distortion of the diffusion measurement is strongest in, but not limited to the contrasting areas.
本研究旨在详细研究钆造影剂对扩散张量成像扫描的影响。由于目前的文献结果相互矛盾，我们在分析中纳入了大量的指标。
本研究纳入了 16 名患有脑内轴内对比增强肿瘤的患者。进行了两次扩散张量成像扫描 - 一次为自然扫描，另一次在应用钆造影剂后进行。不变量指数分数各向异性（FA）、线性、平面和球形指数、迹线、特征值 λ(1)、λ(2)、λ(3)以及扩散张量矩阵 Dxx、Dyy、Dzz、Dxy、Dxz 和 Dyz 的分量图与对比增强区域、肿瘤周围水肿和正常表现的白质中的匹配 ROI 对进行了配准，并进行了统计学比较。
我们观察到在对比后扫描中 FA 显著增加，特征值不成比例地降低。根据这些发现，球形指数降低，线性和平面指数增加。扩散张量矩阵的所有对角分量都显著降低。这些变化在对比增强区域最强，但在肿瘤周围水肿和正常表现的白质中也有明显变化。
钆造影剂给药后进行的扩散张量成像扫描可能会由于测量特征值的不成比例变化而显示出人为增加的 FA 值。这种扩散测量的失真在增强区域最强，但不仅限于此。
