Changes in functional MRI signals after 3D based radiotherapy of glioblastoma multiforme

Abstract

The purpose of our study was to examine the potential effects of conventional 3D based radiotherapy on functional MRI activation areas following the treatment of glioblastoma multiforme. Seventeen patients with a histologically proven glioblastoma multiforme were enrolled in this study. A functional MRI examination was performed alongside the planning CT and conventional MRI prior to the delivery of conventional 3D based radiotherapy. All patients received 3D based postoperative radiotherapy (up to 60 Gy) combined with temozolomide. Follow-up fMRI examinations were performed after completion of the treatment in the 6th week and in 3 months time. Changes of the task related activation areas were registered and analyzed. The difference in changes of high dose and low dose areas of the brain were also registered and analyzed. The comparison of the pretreatment and 6th week control fMRI activation areas revealed significant changes in motor activation and listening tasks in the case of brain areas which received a high dose (over 40 Gy). Based on the population level statistical parametric images (motor activation tasks) acquired at the 6th week control examination, a significant increase of signal was registered in the precuneus region and in the globus pallidus region. When comparing the 6th week and 3rd month activation signals, no significant changes were registered. Our results demonstrate the influence of radiotherapy on functional MRI signals within the human brain. Based on our findings, functional activation transfers from high dose areas to low dose areas. In case of the motor activation tasks, activations of the secondary motor area were observed following radiotherapy.

Attenuation of the BOLD fMRI Signal and Changes in Functional Connectivity Affecting the Whole Brain in Presence of Brain Metastasis

“…Aside from that, several patients in this study had already undergone previous therapies. Alterations in fMRI signals [ 40 ], as well as FC, might be induced by both chemotherapy [ 41 , 42 , 43 ] and radiotherapy [ 44 , 45 ]. Moreover, a possible explanation for altered FC in the presence of BM could also be cerebral reorganization [ 46 ].…”

Radiation-agent combinations for glioblastoma: challenges in drug development and future considerations

“…Radiomics enables high-output extraction of medical image quantitative features, providing a comprehensive non-invasive assessment of tumor phenotype [42]. Radiomics has spurred interest in near-term research initiatives that include photon and particle radiotherapy delivery platforms driven by treatment planning software utilizing (a) biologic rather than physical dose [43], (b) grid therapy [44], and (c) avoidance algorithms for eloquent brain [45]. How best to integrate radiomics into clinical trials remains under study.…”

Neurotoxicity from Old and New Radiation Treatments for Brain Tumors

“…Functional MRI, which indirectly measures neural activity through the measurement of changes in blood flow, has observed that after high radiotherapy doses there is a decrease in neural activation during motor and sensory tasks that lasts several months [ 124 ]. Moreover, MR spectroscopy has reported a molecular derangement not only in areas of the brain receiving high doses of radiotherapy, but also in unexposed regions [ 125 , 126 ], probably related to a release of cytokine cascades.…”