BACKGROUND Focal cortical dysplasia (FCD) is a neuronal migration disorder and is a major cause of drug-resistant epilepsy. However, many focal abnormalities remain undetected during routine visual inspection, and many patients with histologically confirmed FCD have normal fluid-attenuated inversion recovery (FLAIR-negative) images. The aim of this study was to quantitatively evaluate the changes in cortical thickness with magnetic resonance (MR) imaging of patients to identify FCD lesions from FLAIR-negative images. METHODS We first used the three-dimensional (3D) Laplace method to calculate the cortical thickness for individuals and obtained the cortical thickness mean image and cortical thickness standard deviation (SD) image based on all 32 healthy controls. Then, a cortical thickness extension map was computed by subtracting the cortical thickness mean image from the cortical thickness image of each patient and dividing the result by the cortical thickness SD image. Finally, clusters of voxels larger than three were defined as the FCD lesion area from the cortical thickness extension map. RESULTS The results showed that three of the four lesions that occurred in non-temporal areas were detected in three patients, but the detection failed in three patients with lesions that occurred in the temporal area. The quantitative analysis of the detected lesions in voxel-wise on images revealed the following: specificity (99.78%), accuracy (99.76%), recall (67.45%), precision (20.42%), Dice coefficient (30.01%), Youden index (67.23%) and area under the curve (AUC) (83.62%). CONCLUSION Our studies demonstrate an effective method to localize lesions in non-temporal lobe regions. This novel method automatically detected FCD lesions using only FLAIR-negative images from patients and was based only on cortical thickness feature. The method is noninvasive and more effective than a visual analysis for helping doctors make a diagnosis.

中文翻译：

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根据皮质厚度从FLAIR阴性图像中检测局灶性皮质发育异常病变。

背景技术局灶性皮质发育不良（FCD）是一种神经元迁移疾病，并且是耐药性癫痫的主要原因。但是，在常规的目视检查过程中仍未发现许多局灶异常，并且许多经组织学证实为FCD的患者均具有正常的液体衰减倒置恢复（FLAIR阴性）图像。这项研究的目的是通过磁共振（MR）成像定量评估患者皮层厚度的变化，以从FLAIR阴性图像中识别FCD病变。方法我们首先使用三维（3D）Laplace方法来计算个体的皮层厚度，然后基于所有32位健康对照者获得皮层厚度平均图像和皮层厚度标准差（SD）图像。然后，通过从每个患者的皮层厚度图像中减去皮层厚度平均图像，然后将结果除以皮层厚度SD图像，即可计算出皮层厚度延伸图。最后，从皮层厚度延伸图将大于3的体素簇定义为FCD病变区域。结果结果表明，在三例患者中发现了在非颞区发生的四个病变中的三个，但是在三例中出现了在颞部病变的患者中，检测失败。在图像上以体素方式对检测到的病变进行定量分析显示：特异性（99.78％），准确性（99.76％），召回率（67.45％），准确性（20.42％），骰子系数（30.01％），尤登指数（67.23％）和曲线下面积（AUC）（83.62％）。结论我们的研究证明了一种在非颞叶区域定位病变的有效方法。这种新颖的方法仅使用来自患者的FLAIR阴性图像自动检测FCD病变，并且仅基于皮层厚度特征。该方法是无创的，比视觉分析更有效，可帮助医生进行诊断。