Advances of MR imaging in glioma: what the neurosurgeon needs to know

Abstract

Glial tumors and especially glioblastoma present a major challenge in neuro-oncology due to their infiltrative growth, resistance to therapy, and poor overall survival-despite aggressive treatments such as maximal safe resection and chemoradiotherapy. These tumors typically manifest through neurological symptoms such as seizures, headaches, and signs of increased intracranial pressure, prompting urgent neuroimaging. At initial diagnosis, MRI plays a central role in differentiating true neoplasms from tumor mimics, including inflammatory or infectious conditions. Advanced techniques such as perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) enhance diagnostic specificity and may prevent unnecessary surgical intervention. In the preoperative phase, MRI contributes to surgical planning through the use of functional MRI (fMRI) and diffusion tensor imaging (DTI), enabling localization of eloquent cortex and white matter tracts. These modalities support safer resections by informing trajectory planning and risk assessment. Emerging MR techniques, including magnetic resonance spectroscopy, amide proton transfer imaging, and 2HG quantification, offer further potential in delineating tumor infiltration beyond contrast-enhancing margins. Postoperatively, MRI is important for evaluating residual tumor, detecting surgical complications, and guiding radiotherapy planning. During treatment surveillance, MRI assists in distinguishing true progression from pseudoprogression or radiation necrosis, thereby guiding decisions on additional surgery, changes in systemic therapy, or inclusion into clinical trials. The continued evolution of MRI hardware, software, and image analysis-particularly with the integration of machine learning-will be critical for supporting precision neurosurgical oncology. This review highlights how advanced MRI techniques can inform clinical decision-making at each stage of care in patients with high-grade gliomas.

Keywords: 5ALA - 5-aminolevulinic acid; CBV-cerebral blood volume; CEST-chemical exchange saturation transfer; DTI-diffusion tensor imaging; FMRI-functional MRI; GKS-gamma knife surgery; LITT-Laser induced thermal therapy; MRI-magnetic resonance imaging; RT-radiation therapy; T2FLAIR-T2 fluid attenuated inversion recovery.

Fig. 1

Patient with a molecular glioblastoma (histopathological confirmation, IDH wild type). Upper left, DWI with high signal intensity, lower left, ADC map with isointensity. Upper right, T1 post contrast without enhancement, lower right, dynamic susceptibility perfusion MRI with high cerebral blood volume

Fig. 2

Patient with an astrocytoma grade 4 (IDH-mutated). MR multivoxel spectroscopy with high choline and low NAA inside the tumor. Metabolic ratios Choline/NAA and Choline/Creatin are also high

Fig. 3

Patient with a glioblastoma in the left temporal lobe. Functional MRI depicting left sided language lateralization

Fig. 4

Patient with a glioblastoma (same as in Fig. 3) with the corticospinal tract depicted from MR tractography located medial to the tumor in the left temporal lobe

Fig. 5

Patient with a glioblastoma investigated during treatment surveillance and Bevacizumab treatment. Lower row, before Bevacizumab treatment, and upper row after Bevacizumab treatment. After treatment, the contrast enhancement is slightly less pronounced at T1 post contrast images (left column), while the T2-FLAIR signal changes still continues to progress (second column from the left), the ADC-signal is not facilitated as would be expected in areas with less cell density, and the perfusion images shows that there still is hyperperfused progressing tumor areas