Objective To study MRI
diagnosis and
differential diagnosis of posterior fossa
cyst with
hydrocephalus in
children.
Methods MRI performances and clinical data of 56
children with
cyst in the posterior fossa and
hydrocephalus were analyzed and classified.Results 12 cases of
Dandy-Walker malformation(DWM)showed absence of the vermis at different degrees and the enlarged
fourth ventricle widely communicating with the large posterior fossa
cyst,accompanied by elevation of the tentorium
cerebella and
hydrocephalus,in which 1 case combined with callosal agenesis,1 case with subependymal
gray matter heterotopia and 1 case with subependymal
gray matter heterotopia and small
occipital encephalocele.9 cases of Blake'
s pouch cyst(BPC)showed mildly
dilatation of the
fourth ventricle,and the
cyst was below the cerebellar and
hydrocephalus.Neither cerebellar hypoplasia nor elevation of the tentorium
cerebella was observed. The postirior wall of the
cyst was observed on sagittal T 2WI in 5 cases.The
choroid plexus of the fourth ventricular moving to the top wall of the
cyst were seen on thin sagittal T 2WI in 1 case.35 cases of
arachnoid cyst(AC)showed aggregation of
cerebrospinal fluid,and the fourth ventricular and
aqueductal stenosis at different degrees and
hydrocephalus.Conclusion MRI has evident advantages at
diagnosis and
differential diagnosis of cystic malformations of the posterior fossa with
hydrocephalus,especially on sagittal MRI.