MRI Assessment Of Fetal Cerebellar Vermis Development

ObjectiveTo measure the main dimensions of fetal cerebellar vermis and assess its development. To explore the MRI features of Dandy-Walker syndrome (DWS)Materials and Methods52 of the 63 fetal specimens (gestational age 15-40 weeks) scanned on a 3.0T MR system met the inclusion criteria.the anterior posterior diameter (APD)of cerebellar vermis,the height of anterior vermis and posterior vermis were measured and analized. The MRI findings of DWS (n=6) confirmed by MRI scan were analyzed retrospectively.ResultsAPD and the height of anterior vermis and posterior vermis increased linearly with gestational age,the height of anterior vermis was greater than posterior vermis, P<0.05. primary and inferoposterior fissure could be visualized on midsagittal T1 and T2-weighted images. The main MRI findings of DWS were observed as follows:absence of the cerebellar vermis or partial agenesis of the separative cerebellar hemispheres,cystic dialation of the fourth ventricle communicating with enlargement of posterior fossa cyst ConclusionThe development of fetal cerebellar vermis could be assessed by MRI after a gestational age of 17 weeks. There are characteristic MRI findings in the DWS and MRI scan is a valuable method for an early diagnosis of DWS.