DOI: 10.3171/2012.2.JNS102032

OligOdendrOglial tumors are predominantly su-pratentorial, diffuse primary brain tumors and represent the second most common glioma in adults after glioblastoma multiforme.11 Closely related to diffuse fibrillary astrocytomas both clinically and biologi-cally, they are classified as pure oligodendrogliomas or mixed oligoastrocytomas and are graded histologically as low grade (WHO Grade II) or anaplastic (WHO Grade III).20 Similar to fibrillary astrocytomas, oligodendroglial tumors that show enhancement on conventional MRI af-ter administration of gadolinium contrast medium have long been thought to portend a poorer prognosis.18,22 In fact, the presence of contrast enhancement has been con-sidered a central criterion in some grading systems for oligodendroglial tumors.10 Furthermore, the presence of Magnetic resonance imaging volumetric assessment of the extent of contrast enhancement and resection in oligodendroglial tumors Clinical articl