Neuroradiological viewpoint on the diagnostics of space-occupying brain lesions.

Conventional magnetic resonance (MR) imaging of space-occupying lesions may answer most of the questions concerning the diagnosis and subsequent treatment strategies if patient age, clinical and paraclinical findings are considered as well. However, crucial and relevant differential diagnoses require additional MR methods, such as diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and magnetic resonance spectroscopy (MRS). In necrotic ring-enhancing lesions DWI may detect inflammatory processes, whereas characteristics of the peritumoral area may help to distinguish between metastases and glioblastomas. In solid tumors DWI, PWI and MRS may also aid the differentiation between low-grade gliomas and malignant tumors, such as gliomas WHO (World Health Organization) grade III and IV and lymphomas. This review briefly explains special MR methods with respect to brain tumors and illustrates the diagnostic pathways necessary for supplying a reliable diagnosis as well as optimal pre-operative imaging of space-occupying brain lesions.