Department of Radiology and Neuroradiology, Children's Hospital V. Buzzi, Via Castelvetro 32, Milan 20154, Italy.
AJR Am J Roentgenol. 2012 Feb;198(2):439-47. doi: 10.2214/AJR.11.6662.
Limited information is available about the development of focal cortical gyration anomalies in the human brain. Using prenatal MRI, we characterized focal cortical gyration anomalies at an early formative stage and sought clues about the mechanisms of their development.
From a large prenatal MRI database, 30 cases (gestational age, ≤ 24 weeks) with reported focal distortion of the cortical rim profile were selected. Eight cases were matched with histologic examinations; another seven had prenatal MRI, MRI autopsy, or postnatal MRI follow-up; and 15 had no follow-up but did present analogous abnormal cortical features. Focal cortical gyration anomalies were detectable when the brain was still smooth (i.e., physiological lissencephaly).
Four patterns of cortical plate anomaly were identified: wartlike (11 cases), abnormal invaginating sulcus (11 cases), sawtooth (six cases), and single or multiple bumps (two cases). A thinned or blurred subplate and intermediate zone in the focal cortical gyration anomaly site was detected in 80% of cases. All but two cases had other intracranial anomalies. Seven cases were classified as hypoxic-ischemic, five as genetic, and three as infective. In 15 cases, the cause could not be established. In five fetuses with further intrauterine or postnatal MRI, focal cortical gyration anomalies increased in complexity, fulfilling postnatal imaging criteria of polymicrogyria.
Focal cortical gyration anomalies can be detected at the early sulcation process stage. The process leading to abnormal gyration may evolve faster than physiologic ones and seems to be related to alterations of parenchymal layering occurring before 24 weeks' gestation. Most focal cortical gyration anomalies evolve toward what is currently considered polymicrogyria.
有关人类大脑皮质局部回旋异常发育的信息有限。我们使用产前 MRI 来描述早期形成阶段的皮质局部回旋异常，并寻找有关其发育机制的线索。
从一个大型产前 MRI 数据库中，选择了 30 例（胎龄≤24 周）报告有皮质边缘轮廓局部变形的病例。8 例与组织学检查相匹配；另 7 例有产前 MRI、MRI 尸检或产后 MRI 随访；15 例无随访，但存在类似的异常皮质特征。当大脑仍然光滑（即生理性无脑回畸形）时，可检测到皮质局部回旋异常。
确定了 4 种皮质板异常模式：疣状（11 例）、异常内陷沟（11 例）、锯齿状（6 例）和单个或多个隆起（2 例）。在 80%的病例中，在局部皮质回旋异常部位检测到变薄或模糊的基板和中间带。除了 2 例外，所有病例均存在其他颅内异常。7 例分类为缺氧缺血性，5 例为遗传性，3 例为感染性。在 15 例病例中，原因无法确定。在 5 例具有进一步宫内或产后 MRI 的胎儿中，局部皮质回旋异常的复杂性增加，符合产后影像学多微小脑回的标准。
皮质局部回旋异常可在早期脑回发育过程中检测到。导致异常回旋的过程可能比生理性过程更快，似乎与 24 周前发生的实质分层改变有关。大多数皮质局部回旋异常向目前认为的多微小脑回发展。
