不同病理类型局灶性皮质发育不良的MRI特征

MRI characteristics of various pathological subtypes of focal cortical dysplasia

目的 总结局灶性皮质发育不良（FCD）的MRI特征性表现,探讨不同病理类型FCD各自的特异性MRI征象.方法 回顾性分析经病理证实的44例FCD患者的MRI表现.将44例患者根据病理检查结果分为FCD Ⅰ型和Ⅱ型,观察以下MRI征象在两种类型中的出现情况：（1）局灶性皮层增厚;（2）灰、白质分界不清;（3）液体衰减反转恢复（FLAIR）序列和（或）T2WI上白质内向脑室方向延伸的锥形异常增高信号;（4）脑叶发育不全;（5）FLAIR上灰质信号强度增高;（6）T2WI上灰质信号强度增高;（7）FLAIR上皮层下白质信号强度增高;（8）T2WI上皮层下白质信号强度增高;（9）T1WI上皮层下白质信号强度减低.2组间的比较采用χ2检验及校正χ2检验.结果 44例FCD患者中FCD Ⅰ型30例,FCDⅡ型14例.共32例患者MRI表现异常,灰、白质分界不清为最常见征象（23例）.其中FCD Ⅰ型患者中MRI表现异常者21例,特征性表现为脑叶发育不全11例,FCDⅡ型脑叶发育不全0例,两种类型间差异有统计学意义（连续性校正χ2=5.0286,P=0.0249）.FCDⅡ型患者中MRI表现异常者11例,特征性表现为局灶性皮层增厚10例,FCD Ⅰ型为11例（χ2=4.6234,P=0.0315）;FLAIR上白质信号增高9例,FCD Ⅰ型为7例（χ2=6.9180,P=0.0085）;白质内向脑室方向延伸的锥形异常增高信号4例,FCD Ⅰ型为0例（连续性校正χ2=6.2883,P=0.0122）;差异均有统计学意义.其他征象两种类型间差异无统计学意义.结论 不同病理类型FCD的MRI表现各有特点,了解这些特点有助于不同病理类型FCD的早期诊断和术前评估.

Objective To summarize MRI findings of focal cortical dysplasia （FCD）, analyze MRI characteristics of various pathological subtypes of focal cortical dysplasia. Methods Forty-four patients with FCD were collected. Their MRI findings were analyzed retrospectively. According to pathologic findings, these patients were divided into FCD type Ⅰ group and FCD type Ⅱ group. The following MR signs were observed in the two types of FCD： （ 1 ） Focal thickening of the cortex. （ 2 ） Blurring of the gray matter-white matter junction. （ 3 ） Tapering of white matter signal intensity alteration toward the ventricle on FLAIR and on T2WI. （4）Focal brain hypoplasia. （5）Increased signal intensity of gray matter on FLAIR. （6）Increased signal intensity of gray matter on T2 WI. （ 7 ） Increased signal intensity of subcortical white matter on FLAIR.（8） Increased signal intensity of subeortical white matter on T2WI. （9） Decreased signal intensity of subcortical white matter on T1 WI. The χ2 tests and corrected χ2 tests were used for comparison between the two groups. Results In the 44 cases, there were 30 cases with FCD type Ⅰ and 14 cases with FCD type Ⅱ. FCD was identified by MRI in 32 cases. Blurring of the gray-white matter junction is the most common sign of FCD （23 cases）. There were 21 cases identified by MRI in FCD type Ⅰ group. Focal brain hypoplasia is a typical sign of FCD type Ⅰ , which was found in 11 cases in FCD type Ⅰ group but none in FCD type Ⅱ group. There was statistically significant difference between the two groups （continuity corrected χ2 =5. 0286,P =0. 0249） . In FCD type Ⅱ group, 11 cases were identified by MRI. Increased cortical thickness was found in 10 eases in FCD type Ⅱ group and 11 cases in FCD type Ⅰ group （ χ2 =4. 6234 ,P =0. 0315）. Increased signal intensity of subcortical white matter on FLAIR was found in 9 cases in FCD type Ⅱ group and 7 cases in FCD type Ⅰ group （χ2 =6.9180,P =0.0085）. Tapering of white matter signal intensity alteration toward the ventricle was found in 4 cases in FCD type Ⅱ group and none in FCD type Ⅰ group （ continuity corrected χ2 = 6. 2883, P = 0. 0122）. The above-mentioned three MRI findings showed statistically significant difference between the two groups and were features of FCD type Ⅱ.All of the other MRI findings showed no statistically significant difference between the two groups. Conclusions Different pathological subtypes of FCD have different MRI characteristics. It is helpful to make preoperative diagnosis and planning.