Beautiful Eyes Guiding Powerful Hands – The Role of Intraoperative Imaging Techniques in the Surgical Management of Gliomas

European Neurological Review, 2011;6(3):208-212 DOI:


The aims of the surgical management of cerebral gliomas are to achieve the widest feasible resection and preserve the patient’s functional integrity. This results in an improved survival rate and a favourable quality of life. When treating this disease, current neuroradiological techniques are important for preoperative depiction and planning, and intraoperative image-guided resection, especially when the tumour involves eloquent cortical and subcortical structures. Knowledge of these techniques and their limitations, and appropriate expertise are therefore necessary to gain the complete benefit of their diagnostic and therapeutic power.
Keywords: Magnetic resonance imaging (MRI), diffusion tensor imaging-fibre tractography (DTI-FT), functional MRI, neuronavigation, glioma
Disclosure: The authors have no conflicts of interest to declare.
Received: May 18, 2011 Accepted September 01, 2011
Correspondence: Lorenzo Bello, Istituto Clinico Humanitas, Via Manzoni 56, 20089, Rozzano, Milan, Italy. E:

Gliomas are primitive cerebral tumours representing a heterogeneous group of intra-axial central nervous system neoplasms of glial origin with different histology, behaviour, molecular characteristics, natural history and thus prognosis.1–4 Four distinct tumour grades have been identified according to the degree of malignancy, as reported in the World Health Organization (WHO) classification.5 The low-grade gliomas (LGGs) commonly refer to grade 2 astrocytoma, grade 2 oligoastrocytoma and grade 2 oligodendroglioma, while high-grade gliomas (HGGs) refer to the grade 3 anaplastic variants of astrocytomas, oligodendrogliomas and oligoastrocytomas, and to the grade 4 gliomas, specifically glioblastomas, giant cell glioblastomas and gliosarcomas. LGGs and HGGs differ in terms of epidemiology, clinical features, proliferation rate, mitotic activity and angiogenesis phenomena, and thus require specific treatment protocols.2–4,6,7

Several investigations in the past two decades have increasingly supported the role and the oncological efficacy of surgically managing LGGs and HGGs.1–3,7–13 Current neurosurgical treatment has several aims: to obtain adequate and representative tissue specimens for an effective histological diagnosis and proper genetic and molecular analysis (MGMT methylation status, 1p19q loss of heterozigosity, isocitrate dehydrogenase 1 mutation); to achieve maximum cytoreduction and to avoid or reduce eventual malignant transformation; to relieve the patient’s neurological signs and symptoms, including seizure occurrence; to minimize postoperative morbidity and preserve the best achievable quality of life. Indeed, the extent of resection (EOR) is significantly related to overall and progression-free survival, as demonstrated in a series of previous investigations.3,7,8,10,14

To maximise the EOR while minimising postoperative morbidity and preserving the patient’s integrity, it is mandatory during surgery to correctly identify functional relevant brain regions, or eloquent areas, which are often infiltrated or dislocated by gliomas, particularly in the case of LGGs. Eloquent supratentorial brain areas are practically defined as areas relevant for the performance of basic neurological functions, such as sensory, motor, language and visual cortical and subcortical structures.15,16

A composite setting of neuroradiological,17 neurophysiological18 and neuropsychological19 assets is available at the pre- and intraoperative stage, with so-called functional brain mapping and monitoring techniques allowing the identification of specific cortical and subcortical functional structures. Using these techniques may impact on the EOR and thus on the long-term survival of patients affected by LGGs.10,15,16 Contemporary imaging techniques are essential at all stages of managing gliomas.20 The authors thus aim to explore and critically analyse different imaging technologies currently used in routine clinical practice at the pre- and intraoperative stage in the surgical management of gliomas. The advantages, limitations and the potential of conventional and advanced magnetic resonance imaging (MRI) and ultrasound techniques are discussed.

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Keywords: Magnetic resonance imaging (MRI), diffusion tensor imaging-fibre tractography (DTI-FT), functional MRI, neuronavigation, glioma