Characterizing the microstructural basis of "unidentified bright objects" in neurofibromatosis type 1: A combined in vivo multicomponent T2 relaxation and multi-shell diffusion MRI analysis
Characterizing the microstructural basis of "unidentified bright objects" in neurofibromatosis type 1: A combined in vivo multicomponent T2 relaxation and multi-shell diffusion MRI analysis
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DOI：
10.1016/j.nicl.2014.04.005
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发表时间：
2014-01-01
影响因子：
4.2
通讯作者：
Emsell, Louise
中科院分区：
文献类型：
--
作者：
Billiet, Thibo;Maedler, Burkhard;Emsell, Louise
“不明明亮物体”（UBOs）（神经纤维瘤病-1 （NF1）患者在t2加权磁共振（MR）脑部扫描中看到的高强度区域）的组织病理学基础尚不清楚。新的基于体内mri的技术（多指数T2弛豫（MET2）和扩散磁共振成像（dMRI））提供了与微结构变化相关的测量。我们结合了这些方法，并提出了以前未报道的NF1体内UBO微观结构的数据。方法：采集17例NF1患者的3-Tesla dMRI数据，覆盖30个白质ubo。计算UBO部位和对侧正常白质（cNAWM）的扩散张量、峰度、神经突取向和弥散密度成像参数。对24对UBO-cNAWM进行MET2参数分析。结果：髓磷脂水组分及细胞内和细胞外水组分未见明显变化。ubo组IE水的平均T2时间显著增高。与cNAWM相比，UBOs还表现出轴向、径向和平均扩散系数的增加，分数各向异性、平均峰度和神经突密度指数的降低。神经突取向、分散和各向同性流体分数未发生变化。结论：我们的研究结果表明，ubo不太可能出现脱髓鞘和轴突变性，这可能主要是由细胞内和细胞外水池的t2值升高引起的。这可能是由于微结构区隔的改变和“细胞外样”细胞内水的增加，可能是由于髓内水肿。这些发现证实了结合dMRI和MET2来表征体内T2高信号的显微结构基础的附加价值。(C) 2014年作者。Elsevier Inc.出版。
Introduction: The histopathological basis of "unidentified bright objects" (UBOs) (hyperintense regions seen on T2-weighted magnetic resonance (MR) brain scans in neurofibromatosis-1 (NF1)) remains unclear. New in vivo MRI-based techniques (multi-exponential T2 relaxation (MET2) and diffusion MR imaging (dMRI)) provide measures relating to microstructural change. We combined these methods and present previously unreported data on in vivo UBO microstructure in NF1.Methods: 3-Tesla dMRI data were acquired on 17 NF1 patients, covering 30 white matter UBOs. Diffusion tensor, kurtosis and neurite orientation and dispersion density imaging parameters were calculated within UBO sites and in contralateral normal appearing white matter (cNAWM). Analysis of MET2 parameters was performed on 24 UBO-cNAWM pairs.Results: No significant alterations in the myelin water fraction and intra-and extracellular (IE) water fraction were found. Mean T2 time of IE water was significantly higher in UBOs. UBOs furthermore showed increased axial, radial and mean diffusivity, and decreased fractional anisotropy, mean kurtosis and neurite density index compared to cNAWM. Neurite orientation dispersion and isotropic fluid fraction were unaltered.Conclusion: Our results suggest that demyelination and axonal degeneration are unlikely to be present in UBOs, which appear to be mainly caused by a shift towards a higher T2-value of the intra-and extracellular water pool. This may arise from altered microstructural compartmentalization, and an increase in 'extracellular-like', intracellular water, possibly due to intramyelinic edema. These findings confirm the added value of combining dMRI and MET2 to characterize the microstructural basis of T2 hyperintensities in vivo. (C) 2014 The Authors. Published by Elsevier Inc.