Magnetic Resonance Imaging Characteristics of Glioblastoma Multiforme: Implications for Understanding Glioma Ontogeny

Abstract

BACKGROUND Identifying the origin of gliomas carries important implications for advancing the treatment of these recalcitrant tumors. Recent research promotes the hypothesis of a subventricular zone (SVZ) origin for the stemlike gliomagenic cells identified within human glioma specimens. However, conflicting evidence suggests that SVZ-like cells are not uniquely gliomagenic but this capacity may be shared by cycling progenitors distributed throughout the subcortical white matter (SCWM). OBJECTIVE To review radiological evidence in glioblastoma multiforme (GBM) patients to provide insight into the question of glioma ontogeny. METHODS We explored whether GBMs at first diagnosis demonstrated a pattern of anatomic distribution consistent with origin at the SVZ through retrospective analysis of preoperative contrast-enhanced T1-weighted magnetic resonance images in 63 patients. We then examined the relationship of tumor volume, point of origin, and proximity to the ventricles using a computer model of glioma growth. RESULTS Fewer than half of the GBMs analyzed had contrast-enhancing portions that contacted the ventricle on preoperative imaging. A strong correlation was found between tumor volume and the distance between the contrast-enhancing edge of the tumor and the ventricle, demonstrating that tumors abutting the ventricle are significantly larger than those that do not. The lesions simulated by the computer model validated our assumption that tumors that are radiographically distant from the ventricles are unlikely to have originated in the SVZ and supported our hypothesis that as they grow, the edges of all tumors will near the ventricles, regardless of their point of origin. CONCLUSION This work offers further support for the hypothesis that the origins of GBMs are at sites distributed throughout the white matter and are not limited to the region of the SVZ.

Can lateral ventricle contact predict the ontogeny and prognosis of glioblastoma?

“…LVC was significantly correlated with tumor size (Fig. 2), consistent with a report that tumors abutting the ventricle were significantly larger than those that do not [10]. These results provide evidence that tumors with ventricular contact are a mass growing in a confined intracranial space that do not necessarily reflect a periventricular origin.…”

“…These results provide evidence that tumors with ventricular contact are a mass growing in a confined intracranial space that do not necessarily reflect a periventricular origin. Using a computer model to simulate glioma growth, these investigators proposed that tumors originating in the SVZ or in other sites may grow and achieve ventricular contact before detection [10]. Thus, the point of origin of glioblastomas cannot be determined by LVC in preoperative MRI scans.…”

“…Moreover, there is evidence that LVC may not reflect the point of origin of glioblastomas, and cannot be used to determine the cell of origin [10]. Although some authors have shown more ''stemness'' in the SVZ, location around the ventricle does not imply that these tumors began there, but it may have spread there from other locations.…”

Mesenchymal/proangiogenic factor YKL-40 related to glioblastomas and its relationship with the subventricular zone

“…Although RG cells maintain a close contact with the SVZ in humans throughout adulthood, its apical processes are shortened by a probable retractable mechanism with posterior acquisition of ependymal characteristics, suggesting that RG cells turn into astrocytes, carried out by a mechanism not well understood [10,75], although the factors responsible for radial glia and their maintenance are lost during development.…”

The human battle with glioblastoma multiforme: A true challenge

“…Diffusion Tensor Imaging (DTI) is commonly used to identify tumor infiltration into the parenchyma of the brain by providing a picture of the actual neurons of the brain in relation to the tumor. This imaging modality, along with neuronavigation guidance, are used intraoperatively during resection of the tumors for maximal patient safety and outcome [9][10][11][12][13][14][15][16][17][18][19][20].…”