lissencephaly fetal ultrasound

Ultrasound diagnosis:The whole or parts of the surface of the brain appear smooth with lack of development of brain folds (gyri) and grooves (sulci).Prenatal diagnosis is very difficult but suspicion could be raised >24 weeks’ gestation. The parieto-occipital and Sylvian fissures appear flat and the subarachnoid space is usually increased.In all cases of apparently isolated brain abnormalities, such as ventriculomegaly and agenesis of the corpus callosum, a detailed follow-up scan should be arranged at around 26 weeks to exclude an underlying lissencephaly.There are 2 types of lissencephaly:Type I: agyria with lack of neuronal migration. The cortex is smooth and thick.Type II: extensive and anarchic migration with lack of layering. The cortex is described as “cobblestone”.