Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom.
Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London WC1N 3BG, United Kingdom.
Epilepsy Res. 2014 Feb;108(2):336-9. doi: 10.1016/j.eplepsyres.2013.11.004. Epub 2013 Nov 17.
Malformations of cortical development (MCD), particularly focal cortical dysplasia (FCD), are a common cause of refractory epilepsy but are often invisible on structural imaging. NODDI (neurite orientation dispersion and density imaging) is an advanced diffusion imaging technique that provides additional information on tissue microstructure, including intracellular volume fraction (ICVF), a marker of neurite density. We applied this technique in 5 patients with suspected dysplasia to show that the additional parameters are compatible with the underlying disrupted tissue microstructure and could assist in the identification of the affected area. The consistent finding was reduced ICVF in the area of dysplasia. In one patient, an area of reduced ICVF and increased fibre dispersion was identified that was not originally seen on the structural imaging. The focal reduction in ICVF on imaging is compatible with previous iontophoretic data in surgical specimens, was more conspicuous than on other clinical or diffusion images (supported by an increased contrast-to-noise ratio) and more localised than on previous DTI studies. NODDI may therefore assist the clinical identification and localisation of FCD in patients with epilepsy. Future studies will assess this technique in a larger cohort including MRI negative patients.
皮质发育畸形（MCD），特别是局灶性皮质发育不良（FCD），是难治性癫痫的常见原因，但在结构成像上往往不可见。NODDI（神经丝取向分散和密度成像）是一种先进的扩散成像技术，可提供组织微观结构的额外信息，包括细胞内体积分数（ICVF），这是神经丝密度的标志物。我们将该技术应用于 5 名疑似发育不良的患者，结果表明，额外的参数与潜在的组织微观结构破坏一致，并有助于识别受影响的区域。病变区域的 ICVF 一致减少。在一名患者中，发现了一个原本在结构成像上看不到的区域，其 ICVF 减少，纤维分散增加。成像上的 ICVF 局灶性减少与手术标本中的离子电泳数据一致，比其他临床或扩散图像更明显（支持增加对比度噪声比），比以前的 DTI 研究更局限。因此，NODDI 可能有助于癫痫患者 FCD 的临床识别和定位。未来的研究将在包括 MRI 阴性患者在内的更大队列中评估该技术。
