鉴别诊断
胼胝体发育异常/发育不良(ACC)
胼胝体正常的发育次序为从前向后,首先是膝部，其次为体部和压部,而位于膝部下缘的胼胝体嘴部最后形成。在影像学上,完全性发育异常包括胼胝体缺如和由于旋转失败所致的扣带回缺如。这种改变可使第三脑室上抬至侧脑室之间,在轴位影像学可见其与侧脑室并行排列,同时可见侧脑室的枕角扩大畸形。白质纤维穿过胼胝体,而非沿侧脑室内缘对齐,并自前向后分布,这些纤维即指 Probst束。在冠状扫描,由于 Probst束的内侧压痕和胼胝体膝部缺如,使得侧脑室额角呈“长角”状。大脑半球内侧脑回呈放射状延伸至第三脑室边缘。ACC几乎均合并其他畸形。胼月体发育不良表现为部分体部、压部和嘴部缺如在鉴别胼胝体发育异常(嘴部缺如)和一些脑拦害疾患时,其关键点就在于胼胝体嘴部是否缺如。在胼胝体异常发育过程中,胼周脂肪瘤常见。
The normal developmental sequence of the corpus callosum is anterior and posterior, followed by the knee, the body and the pressor, and the mouth of the corpus callosum located at the lower edge of the knee is formed finally. On imaging, complete developmental anomalies include corpus callosum absence and cingulate gyrus absence due to rotation failure. This change causes the third ventricle to be raised between the lateral ventricles, which can be seen in axial imaging in parallel with the lateral ventricles, as well as an enlarged occipital horn deformity of the lateral ventricle. The white matter fibers pass through the corpus callosum, not along the inner edge of the lateral ventricle, and are distributed from anterior to posterior. These fibers are known as the Probst tracts. In coronal scanning, the frontal horn of the lateral ventricle was 'long horn' due to the medial indenture of the Probst tract and the absence of the corpus callosum knee. The medial cerebral gyrus radiates to the edge of the third ventricle. ACC almost all combined with other malformations. Body dysplasia subcallosal month as part of the body, and the mouth is absent in the identification of the corpus callosum dysplasia (mouth is absent), and some brain block against disease, the key point lies in the corpus callosum is absent in the mouth. In the process of abnormal development of corpus callosum, the subcallosal weeks lipoma commonly.
胼胝体损伤/脑损伤
大多数肼胝体损伤是由于外科手术,多见于第三脑室内或鞍上占位切除,而创伤和出血在胼胝体损伤中少见。在影像学上,可见损伤区胼胝体缺如,而其余部分则完整。胼胝体嘴部存在即可排除胼胝体发育不良。
Most of the loss of hydrazine callosum is due to surgery, and is most often seen in the third ventricle or sublar resection, while trauma and bleeding are rare in corpus callosum injury. On imaging, the corpus callosum in the lesion area is absent, while the rest is intact. The presence of the mouth of the corpus callosum eliminates dysplasia of the corpus callosum.
前脑无裂畸形
前脑无裂畸形是指一组以双侧大脑半球独立形成障碍为特征的畸形。根据大脑镰和透明隔缺如程度不同,可分为3种类型:无脑叶型、半脑叶型和脑叶型。无脑叶型最严重,可见背侧巨大的大脑半球间囊肿(单一巨大脑室);前部脑实质融合,呈扁平状;同时丘 脑也融合,而胼胝体、大脑镰前部、纵裂和外侧裂均缺如。相关的颅面部畸形包括眶距过窄和腭裂。在半脑叶型中,胼胝体前部包括嘴部缺如而胼胝体后部存在。
Holoprosencephaly is a group of malformations characterized by bilateral hemispheric independence disorders. Depending on the degree of falx and septum absence, there are three types: anencephalic, hemiencephalic, and lobular. The lobules are the most severe, with a large dorsal interhemispheric cyst (single giant ventricle). Anterior parenchyma fused, flattened; The thalamus also fused, while the corpus callosum, anterior falx, longitudinal fissure, and lateral fissure were absent. Related craniofacial deformities include narrow orbital space and cleft palate. In the hemispheres the anterior part of the corpus callosum including the mouth is missing and the posterior part of the corpus callosum is present.
胼胝体体积缩小
胼胝体体积与幕上脑白质体积相关。在髓鞘形成前,胼胝体较薄。在髓鞘形成过程中,胼胝体形成其正常的体积与外形。当幕上脑实质严重受损时,可见部分或全部胼胝体萎缩,因为胼胝体的体积是由参与形成的白质纤维束决定的。在严重脑积水时,由于继发于压力或胼胝体软化会有类似表现。
The volume of corpus callosum correlates with the volume of supratentorial white matter. Before myelin formation, the corpus callosum is thinner. During myelin formation, the corpus callosum forms its normal size and shape. When the supratentorial parenchyma is severely damaged, some or all of the corpus callosum is seen to atrophy, because its volume is determined by the white matter tracts involved in formation. In severe hydrocephalus, similar manifestations may occur due to secondary stress or softening of the corpus callosum.
