Use of Preoperative Ependymal Enhancement on Magnetic Resonance Imaging Brain as a Marker of Grade of Glioma.

Objectives: Neural stem cells within the subventricular zone (SVZ) are thought to be responsible for the origin and the heterogeneous nature of the gliomas. The relationship of the gliomas to the SVZ can be appreciated as ependymal enhancement on contrast magnetic resonance imaging (MRI). This study evaluates the rate of ependymal enhancement and its association with the histopathological grade of gliomas.

Patients and Methods: Seventy-five patients with radiological features of glioma were recruited. Preoperative MRI was evaluated for the presence of ependymal enhancement and fluid-attenuated inversion recovery (FLAIR) signal proximity of tumor to ependyma, and the association to grade was investigated.

Results: Seventy-five patients studied showed a male predominance (62.66%) with a mean age of 44.91 ± 13.64 years. Evidence of ependymal enhancement was positive in 24% ( n = 18), 46.67% ( n = 35) showed no evidence, and in 29.33% ( n = 22), assessment was inconclusive. According to WHO grading, 76% ( n = 57) were high-grade gliomas (HGGs) including Grade III ( n = 17) and Grade IV ( n = 40) and 24% ( n = 18) were low-grade gliomas (LGGs) Grade II. HGGs were significantly associated with ependymal enhancement ( P < 0.01) and FLAIR signal proximity to the ependyma ( P < 0.001). Among HGGs, rate of ependymal enhancement and FLAIR signal proximity was more in Grade IV than Grade III but was not statistically significant ( P > 0.05).

Conclusion: SVZ is associated with HGGs. These MRI features can be helpful in predicting the tumor grade preoperatively and by including LGGs, the role of SVZ in the heterogeneous disease process of glioma can be studied as a whole, not only in the glioblastoma (GBM).