Resting-State Functional Connectome in Patients with Brain Tumors Before and After Surgical Resection

Abstract

High-grade glioma surgery has evolved around the principal belief that a safe maximal tumor resection improves symptoms, quality of life, and survival. Mapping brain function has been recently improved by resting-state functional magnetic resonance imaging (rest-fMRI), a novel imaging technique that explores networks connectivity at "rest."-METHODS: This prospective study analyzed 10 patients with high-grade glioma in whom rest-fMRI connectivity was assessed both in single-subject and in group analysis before and after surgery. Seed-based functional connectivity analysis was performed with CONN toolbox. Network identification focused on 8 major functional connectivity networks. A voxel-wise region of interest (ROI) to ROI correlation map to assess functional connectivity throughout the whole brain was computed from a priori seeds ROI in specific resting-state networks before and after surgical resection in each patient.-RESULTS: Reliable topography of all 8 resting-state networks was successfully identified in each participant before surgical resection. Single-subject functional connectivity analysis showed functional disconnection for dorsal attention and salience networks, whereas the language network demonstrated functional connection either in the case of left temporal glioblastoma. Functional connectivity in group analysis showed wide variations of functional connectivity in the default mode, salience, and sensorimotor networks. However, salience and language networks, salience and default mode networks, and salience and sensorimotor networks showed a significant correlation (P uncorrected <0.0025; P false discovery rate <0.077) in comparison before and after surgery confirming non-disconnection of these networks.-CONCLUSIONS: Resting-state fMRI can reliably detect common functional connectivity networks in patients with glioma and has the potential to anticipate network alterations after surgical resection.

Resting-State Functional Magnetic Resonance Imaging for Surgical Neuro-Oncology Planning: Towards a Standardization in Clinical Settings

“…Rest-fMRI can reliably depict temporally coherent networks, and they are codified in the literature based on their different functions, such as the default mode network (DMN), the sensorimotor network, the auditory network, the visual network, the executive control network, the lateralized frontoparietal network, and the temporoparietal network [5,[16][17][18][19] (Figure 2, Table 1). The proof of the existence of the RSNs is based upon the reproducibility of the networks in the single subject, the consistency of the networks between different sub-jects, and the correspondence of the cortical areas identified with different methods of study [5,6,20,21]. Therefore, rest-fMRI is a valid method to evaluate the intrinsic functional architecture, or "connectome," of the human brain [5] (Figure 3) with high reproducibility and reliability.…”

“…The proof of the existence of the RSNs is based upon the reproducibility of the networks in the single subject, the consistency of the networks between different sub-jects, and the correspondence of the cortical areas identified with different methods of study [5,6,20,21]. Therefore, rest-fMRI is a valid method to evaluate the intrinsic functional architecture, or "connectome," of the human brain [5] (Figure 3) with high reproducibility and reliability. The proof of the existence of the RSNs is based upon the reproducibility of the networks in the single subject, the consistency of the networks between different subjects, and the correspondence of the cortical areas identified with different methods of study [5,6,20,21].…”

“…Therefore, rest-fMRI is a valid method to evaluate the intrinsic functional architecture, or "connectome," of the human brain [5] (Figure 3) with high reproducibility and reliability. The proof of the existence of the RSNs is based upon the reproducibility of the networks in the single subject, the consistency of the networks between different subjects, and the correspondence of the cortical areas identified with different methods of study [5,6,20,21]. Therefore, rest-fMRI is a valid method to evaluate the intrinsic functional architecture, or "connectome," of the human brain [5] (Figure 3) with high reproducibility and reliability.…”

“…The proof of the existence of the RSNs is based upon the reproducibility of the networks in the single subject, the consistency of the networks between different subjects, and the correspondence of the cortical areas identified with different methods of study [5,6,20,21]. Therefore, rest-fMRI is a valid method to evaluate the intrinsic functional architecture, or "connectome," of the human brain [5] (Figure 3) with high reproducibility and reliability. Brain MR imaging accurately demonstrates the morphological aspects of brain tumors with standard sequences, such as the three-dimensional (3D) magnetization-prepared rapid acquisition with gradient echo (MPRAGE) T1-weighted images obtained before and after gadolinium enhancement.…”

“…The rest-fMRI sequence is largely available on MRI scanners. By contrast, the main limitation for the clinical implementation of rest-fMRI is the lack of methodology standardization for data processing, which is based on a variety of different software tools and methods that require trained personnel and high skill of expertise [5,6]. Brain MR imaging accurately demonstrates the morphological aspects of brain tumors with standard sequences, such as the three-dimensional (3D) magnetization-prepared rapid acquisition with gradient echo (MPRAGE) T1-weighted images obtained before and after gadolinium enhancement.…”