| Abstract: |
The most devastating congenital problems encountered are developmcntal defects of the brain or sccondary problems arising from these defects. It is important not only to diagnose and to provide appropriate trcatmcnt of these disorders, but also to rccognize conditions, which affect the development of congenital brain lesion.Various imaging modalities such as ultrasound, computed tomography and cercbral angiography can give useful information in diagnosis of congenital brain anomalies. However, they have their limitation in comparison to MRI, which is considered as a non-invasive imaging technique that demonstrates intracranial anatomy and pathology \vithout the use of ionizing radiation. In addition, the high contrast resolution of MR permits highly sensitive assessment of gray and white matter changes, so that it is the best method to evaluate brain development and maturation.Imaging quality of MRI is dependent on various factors, including field strength, scanning sequences, imaging time and patient cooperation.The aim of this study was to identify and study congenital brain lesions with presentation of their diagnostic imaging features by CT and MRI. Initial review of the embryology of the brain, stages of brain development, anatomy of the brain, normal CT and MRI sectional anatomy of the brain and classi fication of congenital brain lesions and the CT and MRI appearance were thoroughly evaluated.finy patients with congenital brain lesions were included III this study. These patients were 24 males and 26 females.;\1\ patients were subjected to axial CT scans and axial ami sagittal Tl weighted images and axial ’1’2 weighted images.The most cOlllmon antenatal risk factor for the development of congenital brain mal formations was found to be consangumeous marrIages. On the other hand, seizures and delayed milestones were the commonest presenting symptoms.The patients \\ere classi fied according to the time of insult of these congenital lesions in prenatal life into 5 groups. Dysgenesis of the corpus callosum was the most commonly encountered lesion among patients of the present study as it was present In I G patients. Each of meningoencephaloceles ami i\rnold-Chiari malformation was present in 7 cases. Moreover, holoprosencephaly and Dandy-Walker syndrome were present in 5 cases. Next in frequency was neuronal heterotopias and hydrancephaly, each was present in 4 cases. Each of cerebellar hypoplasia, cran iosynostosis and \ issencephal y was present \n 3 cases. Hemimegalencepha\y, tuberous sclerosis, aneurysm of veIn of Galen, polymicrogyria and schizencephaly, each was present in only 2 cases. finally, Sturge-Weber syndrome was present in one case. Clinical and radiological imaging features for each disease were demonstrated in view of other available published data.From the present study, it can be concluded that:1- Congenital brain malformations are considered as major disabling physical and mental problems among in fants and young ch i Idren.2- Seizures and delayed milestones in infants and children are important alarming symptoms for congenital brain malformations.3- Various prenatal risk factors that might contribute to the development of congenital brain malformations includingcon5angu i n i ty, maternal illness or med ication abuse duri ng pregnancy should be thoroughly evaluated.4- Congenital brain malformation arc relati”ely COlllmon, especially dysgenesis of the corpus callosum, Arnold-Chiari mal formation and mell i ngncncephaloce le5.5- CT imaging of the brain is a good screening modality for evaluation of cl1ngcnital brain anomalies and was diagnostic in many of them. 6- CT was superior than (vIRI in diagnosis of tuberous sclerosis and Sturge- \Veber syndrome, owing to its carabi I i ty in diagnosis the associated calcifications in these lesions.7- CT with 3D reconstruction was the modality of choice in diagnosis of cases with craniosynostosis due to its ability in diagnosis prcmature closure of the sutures, over lapping of the cranial vault bones and determining the actual size of the fontanelles.8- MRI proved to be an effective, valuable and reliable method thatcould not fully assessed by CT as: -Partial agenesis of the corpus callosulTI.-Arnold-Chiari type I.-Neuronal migrational disorders as lissencephaly, polymicrogyria,neuronal heterotopias and schizencephaly.9- MRI is a safe modality of imaging with absence of ionizing radiation, but on the other hand it needs more times than CT, and this necessitate the administration of general anesthesia for the patients.We recolTImend starting our investigation with MRI in cases, 111 whom neuronal migrational disorders, cephaloceles, corpus callusum disorders or are presented with delayed milestones or epilepsy.We also recommend to start with CT with 3D reconstructions 111 cases with craniosynostosis.
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