Huppertz Hans-Jürgen, Wellmer Jörg, Staack Anke Maren, Altenmüller Dirk-Matthias, Urbach Horst, Kröll Judith
Swiss Epilepsy Centre, Zürich, Switzerland.
Epilepsia. 2008 May;49(5):772-85. doi: 10.1111/j.1528-1167.2007.01436.x. Epub 2007 Nov 28.
To evaluate the potential diagnostic value of a novel magnetic resonance image (MRI) postprocessing technique in subtle forms of subcortical band heterotopia (SBH). The method was introduced to improve the visualization of blurred gray-white matter junctions associated with focal cortical dysplasia but was found to be applicable also to SBH.
In the voxel-based MRI analysis presented here, T1-weighted MRI volume data sets are normalized and segmented using standard algorithms of SPM5. The distribution of gray and white matter is analyzed on a voxelwise basis and compared with a normal database of 150 controls. Based on this analysis, a three-dimensional feature map is created that highlights brain areas if their signal intensities fall within the range between normal gray and white matter and differ from the normal database in this respect. The method was applied to the MRI data of 378 patients with focal epilepsy in three different epilepsy centers.
SBH was diagnosed in seven patients with five of them showing subtle forms of SBH that had gone unrecognized in conventional visual analysis of MRI and were only detected by MRI postprocessing. In contrast to distinct double cortex syndrome, these patients had partial double cortex with SBH mostly confined to posterior brain regions.
The results of this study suggest that a considerable part of cases with SBH might remain unrecognized by conventional MRI. Voxel-based MRI analysis may help to identify subtle forms and appears to be a valuable additional diagnostic tool in the evaluation of patients with cryptogenic epilepsy.
评估一种新型磁共振成像（MRI）后处理技术在皮质下带状异位（SBH）细微形式中的潜在诊断价值。该方法最初是为改善与局灶性皮质发育异常相关的模糊灰白质交界处的可视化而引入的，但后来发现也适用于SBH。
在此呈现的基于体素的MRI分析中，使用SPM5的标准算法对T1加权MRI体积数据集进行归一化和分割。在体素水平上分析灰质和白质的分布，并与150名对照的正常数据库进行比较。基于此分析，创建一个三维特征图，突出显示信号强度落在正常灰质和白质范围之间且在这方面与正常数据库不同的脑区。该方法应用于三个不同癫痫中心的378例局灶性癫痫患者的MRI数据。
在7例患者中诊断出SBH，其中5例表现为SBH的细微形式，在MRI的传统视觉分析中未被识别，仅通过MRI后处理检测到。与明显的双皮质综合征不同，这些患者有部分双皮质，SBH大多局限于后脑区域。
本研究结果表明，相当一部分SBH病例可能在传统MRI检查中未被识别。基于体素的MRI分析可能有助于识别细微形式，似乎是评估隐源性癫痫患者的一种有价值的辅助诊断工具。
