| Keywords [eng] |
fMRI, brain tumors, preoperative mapping, BOLD imaging, neurosurgical mapping, eloquent cortex, language mapping, motor mapping |
| Abstract [eng] |
Background: Brain tumors located in or near eloquent cortical regions present a major neurosurgical challenge, as maximal tumor resection must be balanced against preservation of neurological function. Functional magnetic resonance imaging (fMRI) provides a non-invasive method for preoperative mapping of motor, language, and other functional brain areas. By detecting blood- oxygen-level-dependent (BOLD) signal changes, fMRI can support surgical planning, risk assessment, and patient counseling. However, its clinical reliability is influenced by patient cooperation, methodological variability, and tumor-related neurovascular uncoupling and reorganization. Methods: This narrative literature review evaluated the role of fMRI in patients with brain tumors, with a particular focus on preoperative functional mapping, surgical outcome improvement, and concordance with intraoperative direct cortical stimulation (DCS). A literature search was conducted using PubMed/MEDLINE and the Cochrane Library. Studies were selected according to predefined inclusion and exclusion criteria and structured around three PICO questions addressing diagnostic value, clinical outcomes, and agreement with intraoperative mapping. Results: The reviewed literature demonstrates that fMRI adds clinically relevant functional information beyond conventional structural imaging, particularly for tumors located in or near motor and language cortices. Task-based fMRI remains the most established technique, especially for motor mapping, while resting-state fMRI is increasingly used in patients unable to perform active paradigms. Evidence suggests that preoperative fMRI may contribute to reduced postoperative morbidity and improved functional preservation, especially when integrated into multimodal surgical planning. Concordance with DCS is generally higher for motor mapping than for language mapping, where results are more variable due to the distributed nature of language networks and tumor-induced reorganization. Conclusion: fMRI is a valuable adjunct in the preoperative assessment of brain tumor patients and contributes to individualized neurosurgical planning. Its greatest clinical utility lies in defining the spatial relationship between tumors and eloquent cortex, supporting risk stratification, and guiding intraoperative mapping strategies. Nevertheless, fMRI should not be regarded as a standalone replacement for DCS, but rather as a part of a multimodal approach combining structural MRI, DTI and intraoperative validation. Future standardization of acquisition protocols, analysis methods, and integration of resting-state and AI-based approaches may further enhance its clinical reliability. |
