Kabat Joanna, Król Przemysław
Department of Diagnostic Imaging, Mazowiecki Regional Hospital in Siedlce, Siedlce, Poland.
Pol J Radiol. 2012 Apr;77(2):35-43. doi: 10.12659/pjr.882968.
Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types the lesion seen on MRI may be smaller than the seizure-generating region seen in the EEG. The abnormalities may also involve vital for life brain parts, where curative surgery will not be an option. Therefore, other diagnostic imaging techniques such as FDG PET, MEG, DTI and intra-cranial EEG are widely used to establish the diagnosis and to decide on management.With advances in both genetics and neuroimaging, we may develop a better understanding of patients with drug-resistant epilepsy, which will help us to provide more successful pharmacological and/or surgical treatment in the future.
局灶性皮质发育不良是一种皮质发育畸形，是小儿人群中药物难治性癫痫最常见的病因，在成人中是药物难治性癫痫第二/第三常见的病因。遗传因素和后天因素均参与皮质发育不良的发病机制。人们已提出了许多对局灶性皮质发育不良复杂结构异常的分类——从1971年泰勒等人的分类到2011年布卢姆克对帕尔米尼分类的最新修订。一般来说，皮质发育不良可分为三种类型。I型局灶性皮质发育不良症状表现较轻且发病较晚，更常见于成人，病变多位于颞叶。II型皮质发育不良临床症状通常更严重，多见于儿童。在这种类型中，颞叶外有更广泛的病变，以额叶最为常见。新型III型是上述发育不良之一，并伴有另一种主要病变，如海马硬化、肿瘤、血管畸形或早年获得性病变。脑部MRI成像显示，大多数II型发育不良有异常，而I型皮质发育不良只有部分有异常。MRI成像最常见的表现包括：局灶性皮质增厚或变薄、局灶性脑萎缩区域、灰白质交界模糊、T2加权像和液体衰减反转恢复序列（FLAIR）加权像上灰质和皮质下白质信号增强，且信号常向脑室逐渐变细。根据MRI表现，可区分I型和II型皮质发育不良。要实现无癫痫发作的生活，需要完整切除致痫区。在一组耐药性癫痫患者中，MRI成像对于识别可能从手术治疗中获益的患者非常有帮助。然而，在I型皮质发育不良中，MR成像通常正常，而且在这两种类型中，MRI上看到的病变可能比脑电图上看到的癫痫发作区小。这些异常也可能累及对生命至关重要的脑部区域，在这些区域无法进行根治性手术。因此，其他诊断成像技术，如氟代脱氧葡萄糖正电子发射断层扫描（FDG PET）、脑磁图（MEG）、弥散张量成像（DTI）和颅内脑电图，被广泛用于确立诊断和决定治疗方案。随着遗传学和神经影像学的进展，我们可能会更好地了解耐药性癫痫患者，这将有助于我们在未来提供更成功的药物和/或手术治疗。
