Comparative Analysis Of MR Imaging Between Pleomorphic Xanthoastrocytoma And Ependymoma In The Supratentorial Brain Parenchyma

Objective:By conducting a retrospective analysis of 21 cases of pleomorphic xanthoastrocytoma and 24 cases of ependymoma in the supratentorial brain parenchyma,which were confirmed by pathology.Compare and analyze the clinical and MR characteristics of the lesions in the tow groups,in order to summarize and improve the understanding of such kind of lesions and improve diagnostic accuracy.Methods:From January 2015 to February 2018,21 cases of pleomorphic xanthoastrocytoma and 24 cases of ependymoma in the supratentorial brain parenchyma,which were confirmed by pathology underwent MR scan in the First Affiliated Hospital of Nanchang University and the Second Affiliated Hospital of Nanchang University.The results were analyzed with Independent-Samples T test,and we use the Pearson?² test for the comparison between the two groups.A p value of<0.05 was considered statistically significant.Results:There were 21 cases of pleomorphic astrocytoma in the supratentorial brain parenchyma,including 13 male cases and 8 female cases.The ages ranged from 7 to56 years old,with mean age of 29.0±14.3 years old.Among them,13 cases were less than 30 years old?61.9%?.Pathologic histology results showed that 19 cases were grade II and 2 cases were grade?.Clinical manifestations were epilepsy in 12 cases?57.1%?and non-epilepsy in 9 cases?42.9%?.The lesions occurred at frontal lobe in 8cases?38.1%?,temporal lobe in 9 patients?42.9%?,and 4 other cases?19.0%?in other lobe.5 cases?23.8%?have unclear boundary with lateral ventricles,and 13cases?61.9%?with cerebral pia mater closely related.Tumor morphology was regular in 12 cases?57.1%?and irregular in 9 cases?42.9%?.4 cases?19.0%?were solid,8cases?38.1%?were cystic-solid,9 cases?42.9%?were cystic with wall nodules.7 cases accompanied with septum.The solid part of the tumor on T₁WI showed slight hypointensity.T₂WI is slight hyperintensity;the cystic part on T_lWI showed hypointensity,T₂WI showed hyperintensity.The cystic part on T_l WI showed hypointensity,T₂WI showed hyperintensity.1 case of tumor associated with hemorrhage.1 case of tumor hemorrhage.It showed mild edema in 15 cases?71.4%?,moderate edema in 3 cases?14.3%?,severe edema in 3 cases?14.3%?.Solid parts of the lesions and mural nodule showed obvious enhancement in 19 cases,only 2 cases showed slight enhancement,and just 2 cases showed visualized pia mater enhancement.There were 24 cases of ependymoma in the supratentorial brain parenchyma,including 11 male cases and 13 female cases.The ages ranged from 4 to74 years old,with mean age of 36.8±21.6 years old.Among them,7 cases were less than 30 years old?29.2%?.Pathologic histology results showed that 15 cases?62.5%?were grade II and 9 cases?37.5%?were grade?.Clinical manifestations were epilepsy in 3 cases?12.5%?and non-epilepsy in 21 cases?87.5%?.The lesions occurred at frontal lobe in 11 cases?45.8%?,temporal lobe in 7 patients?29.2%?,and 6 other cases?25.0%?in other lobe.Among them,4 cases?16.7%?have unclear boundary with lateral ventricles,and 9 cases?37.5%?with cerebral pia mater closely related.Tumor morphology was regular in 12 cases?50.0%?and irregular in 12 cases.3 cases?12.5%?were solid,4 cases?16.7%?were cystic,17 cases?70.8%?were cystic-solid,among which,6 cases?25.0%?were cystic with wall nodules.13 cases accompanied with septum.The solid part of the tumor on T₁WI showed slight hypointensity,T₂WI is slight hyperintensity.The signal of 3 cases with hemorrhage was mixed.It showed mild edema in 13 cases?54.2%?,moderate edema in 7 cases?29.2%?,severe edema in 4 cases?16.7%?.Solid parts of the lesions showed obvious enhancement in 23 cases?95.8%?,and no enhancement of the adjacent pia mater was seen.However,1 case showed a cord-like vascular shadow in the parenchyma.By comparing and analyzing the two groups of cases in clinical data and MRI performances,we found that in the supratentorial brain parenchyma,the proportion of patients of PXA group with less than 30 years old was higher than that of ependymoma group,and the difference had statistical significance??²=4.862,p<0.05?.The ratio of epilepsy in the PXA group was greater than that of the ependymoma group,and the difference had statistical significance??²=10.045,p<0.05?.The proportion of patients with grade III in the PXA group was significantly lower than that in the cerebral ependymoma group,and the difference had statistical significance??²=5.917,p<0.05?.Other MRI performances had no statistical significance?p>0.05?.Conclusions:1.The onset age of ependymoma within the brain parenchyma is slightly higher than that of pleomorphic xanthoastrocytoma.In addition,clinical manifestations of epilepsy are more common in PXA,which also have some identification value.2.Pleomorphic xanthoastrocytoma and ependymoma of the supratentorial brain parenchyma are more common in cystic-mixed type.The large cyst with wall nodule is more common in PXA,but not its specific sign.However,compared to PXA,cystic type is more common in cerebral ependymoma.3.For the two groups of patients in this study,the proportion of patients of PXA group with anaplastic features was greater than that of ependymoma group,which means that the ependymoma has higher malignancy rate.However,The PXA overlaps with the cerebral ependymoma significantly in the location,morphology,hemorrhage,peritumoral edema,intracapsular septa and the relationship with the meninges or lateral ventricle,and should be cautious in differential diagnosis.