Novel therapies of central nervous system (CNS) malignancies have evoked the demand to increasingly integrate dedicated imaging techniques into the diagnostic work-up and treatment evaluation in neuro-oncology. In primary and secondary malignancies of the CNS, advanced neuroimaging techniques enable non-invasive assessment of tissue microstructure, cellular and vascular proliferation and capillary permeability. Furthermore, eloquent cortical areas in the vicinity of tumours and the course of white matter pathways are rendered visible to facilitate surgical therapy.
The armamentarium of magnetic resonance (MR) imaging techniques includes diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), diffusion-tensor imaging (DTI), functional MRI (f-MRI) and MR spectroscopy (MRS). Computed tomography perfusion (perfusion CT) may serve as an alternative to magnetic resonance perfusion (perfusion MR). These new imaging techniques lend support to distinguish the primary brain neoplasms from the secondary brain neoplasms, aid in grading of gliomas, delineate infiltration beyond visible boundaries on contrast-enhanced images and thus support guidance for biopsies and surgical resection. Surveillance and treatment monitoring of neoplasms may shift from almost exclusive reliance on contrast enhancement to an imaging approach that combines traditional morphology with advanced “functional” techniques.
Validation of these new developments is ongoing based on the observations in clinical neuro-oncology, radiation oncology, histopathology and neurosurgery. Application of advanced imaging protocols may promise to improve diagnosis, to stratify patients to an increasing diversity of treatment options and potentially individualise therapy.