Abstract
Intracranial gliomas can be clearly revealed based on the preoperative neuroimaging, an intraoperative investigation of frozen or smear sections of the biopsy sample, and detailed postoperative evaluation of the resected tissue using various histopathological, immunohistochemical, and molecular methods. In the majority of cases advanced MRI techniques permit us to establish an accurate diagnosis of the parenchymal brain tumor, however, differentiation of the lesion with cerebral infarction and demyelination disease may be problematic, especially if aggressive surgical resection is under consideration. In such cases functional and metabolic neuroimaging, such as proton MR spectroscopy and positron emission tomography (PET) with methionine, may be extremely useful adjuncts providing valuable diagnostic information. It should be emphasized, that stereotactic biopsy of the brain lesion can be accompanied by sampling errors. In our series the diagnostic accuracy through biopsy in cases of low-grade gliomas was less than 50%. Molecular evaluation of the tissue specimen may be helpful to arrive at a precise diagnosis based on the tissue samples. Intraoperative neuronavigation, which is routinely used in our practice, affords a surgeon precise orientation in the surgical field and tremendously improves the possibilities for aggressive tumor resection. While the available neuronavigation devices may be based on different technical principles and have different tools for data visualization, the optical tracking and display on a PC screen seems to be the most common options. Recently, novel techniques, which permit fusion of the functional data obtained with tractography, the visualized eloquent cortex, and or metabolic information provided by PET, have become available and significantly increase the number of surgical opportunities for aggressive and safe brain turner resections. Nevertheless, understanding and recognizing the possible navigation errors is very important. Particularly, the effect of brain shift can result in 4-8 mm mislocalization errors, which should be compensated for by intraoperative MRI, CT, or ultrasound. Further development of neuronavigation techniques and the creation of preoperative three-dimensional simulation devices for detailed planning of the surgical procedure may result in significant breakthroughs in the surgical management of gliomas.
