Institute of Diagnostic and Interventional Radiology, The Sixth Affiliated People's Hospital, Shanghai Jiao Tong University, No. 600, Yi Shan Road, Shanghai 200233, China.
Neural Plast. 2021 Oct 31;2021:2678379. doi: 10.1155/2021/2678379. eCollection 2021.
This study introduced new MRI techniques such as neurite orientation dispersion and density imaging (NODDI); NODDI applies a three-compartment tissue model to multishell DWI data that allows the examination of both the intra- and extracellular properties of white matter tissue. This, in turn, enables us to distinguish the two key aspects of axonal pathology-the packing density of axons in the white matter and the spatial organization of axons (orientation dispersion (OD)). NODDI is used to detect possible abnormalities of posttraumatic encephalomalacia fluid-attenuated inversion recovery (FLAIR) hyperintense lesions in neurite density and dispersion. . 26 epilepsy patients associated with FLAIR hyperintensity around the trauma encephalomalacia region were in the epilepsy group. 18 posttraumatic patients with a FLAIR hyperintense encephalomalacia region were in the nonepilepsy group. Neurite density and dispersion affection in FLAIR hyperintense lesions around encephalomalacia were measured by NODDI using intracellular volume fraction (ICVF), and we compare these findings with conventional diffusion MRI parameters, namely, fractional anisotropy (FA) and apparent diffusion coefficient (ADC). Differences were compared between the epilepsy and nonepilepsy groups, as well as in the FLAIR hyperintense part and in the FLAIR hypointense part to try to find neurite density and dispersion differences in these parts. . ICVF of FLAIR hyperintense lesions in the epilepsy group was significantly higher than that in the nonepilepsy group ( < 0.001). ICVF reveals more information of FLAIR(+) and FLAIR(-) parts of encephalomalacia than OD and FA and ADC. . The FLAIR hyperintense part around encephalomalacia in the epilepsy group showed higher ICVF, indicating that this part may have more neurite density and dispersion and may be contributing to epilepsy. NODDI indicated high neurite density with the intensity of myelin in the FLAIR hyperintense lesion. Therefore, NODDI likely shows that neurite density may be a more sensitive marker of pathology than FA.
本研究引入了新的 MRI 技术，如神经丝取向弥散和密度成像（NODDI）；NODDI 应用三分区组织模型对多壳 DWI 数据进行分析，允许检查白质组织的细胞内和细胞外特性。这反过来又使我们能够区分轴突病理学的两个关键方面——白质中轴突的堆积密度和轴突的空间组织（取向弥散（OD））。NODDI 用于检测创伤后脑软化 FLAIR 高信号病变中的神经丝密度和弥散的可能异常。26 例与创伤后脑软化 FLAIR 高信号区相关的癫痫患者被纳入癫痫组。18 例创伤后 FLAIR 高信号脑软化区患者被纳入非癫痫组。使用细胞内容积分数（ICVF）通过 NODDI 测量 FLAIR 高信号病变周围脑软化区的神经丝密度和弥散变化，并将这些发现与常规扩散 MRI 参数（即各向异性分数（FA）和表观扩散系数（ADC））进行比较。比较了癫痫组和非癫痫组之间的差异，以及 FLAIR 高信号部分和 FLAIR 低信号部分，以试图在这些部分找到神经丝密度和弥散的差异。癫痫组 FLAIR 高信号病变的 ICVF 明显高于非癫痫组（<0.001）。ICVF 比 OD、FA 和 ADC 提供了更多关于脑软化 FLAIR(+)和 FLAIR(-)部分的信息。癫痫组脑软化区周围 FLAIR 高信号部分的 ICVF 较高，表明该部分可能具有更高的神经丝密度和弥散，可能与癫痫有关。NODDI 显示 FLAIR 高信号病变中神经丝密度较高，提示髓鞘强度。因此，NODDI 可能表明神经丝密度比 FA 更能敏感地反映病理学。
