MRI characteristics of pilomyxoid astrocytoma / 中华放射学杂志

ABSTRACT

Objective To investigate the MRI features of pilomyxoid astrocytoma ( PMA ) in children.Methods MRI features of seven children with pathologically proven PMA in 2011-2013 were retrospectively analyzed.The ages of the patients ranged from 10 months to 32 months at initial diagnosis.Results All tumors were well-circumscribed masses.Six tumors were located in the hypothalamic-chiasmatic-third ventricular region , two tumor involved the bilateral temporal lobe , and one tumor was associated with NF-I.One occurred in the basal ganglia region.Four tumors were solid masses , whereas the other three showed cystic components.Six tumors were hypointense and one was isointense on T 1-weighted image.Five tumors were hyperintense and three were isointense on T 2-weighted image.Four tumors were hypointense , one was iso-hypointense and one was isointense on DWI.After contrast administration , four tumors enhanced homogenously and three tumors enhanced heterogeneously , with intratumoral irregular hypointense region in two tumors and rim enhancement in one tumor.Cerebrospinal fluid ( CSF ) dissemination, hydrocephalus and peritumor edema were observed in 2, 4 and 1 of cases, respectively.Proton magnetic resonance spectrum of two PMA showed elevated Cho /Cr ratios and decreased NAA/Cr ratios.Conclusions The imaging features of pilomyxoid astrocytoma include common origination from the midline of the neuroaxis in younger children about 2-3 years old.The CSF dissemination is common.The presence of hemorrhage and peritumor edema is not common.