Asymmetric tumor‐related alterations of network‐specific intrinsic functional connectivity in glioma patients

Abstract

Resting-state functional MRI (rs-fMRI) allows mapping temporally coherent brain networks, and intra-and inter-network alterations have been described in different diseases. This prospective study investigated hemispheric resting-state functional connectivity (RSFC) differences in the default-mode network (DMN) and frontoparietal network (FPN) between patients with left-and right-hemispheric gliomas (LH PAT, RH PAT), addressing asymmetry effects the tumor might have on networkspecific intrinsic functional connectivity under consideration of the prognostically relevant isocitrate-dehydrogenase (IDH) mutation status. Twenty-seven patients (16 LH PAT, 12 IDH-wildtype) and 27 healthy controls underwent anatomical and rs-fMRI as well as neuropsychological assessment. Independent component analyses were performed to identify the DMN and FPN. Hemispheric DMN-and FPN-RSFC were computed, compared across groups, and correlated with cognitive performance. Patient groups did not differ in tumor volume, grade or location. RH PAT showed higher contra-tumoral DMN-RSFC than controls and LH PAT. With regard to the FPN, contra-tumoral RSFC was increased in both patient groups as compared to controls. Higher contra-tumoral RSFC was associated with worse cognitive performance in patients, which, however, seemed to apply mainly to IDH-wildtype patients. The benefit of RSFC alterations for cognitive performance varied depending on the affected hemisphere, cognitive demand, and seemed to be altered by IDH-mutation status.

Dissociation of structural and functional connectomic coherence in glioma patients

“…29 patients with cerebral glioma (mean age: 50 ± 17 years, 17 males, 28 right-handed, 19 LH PAT, 15 IDHmut) and 27 healthy controls (mean age: 46 ± 14 years, 17 males, 26 right-handed) were included in the study. They were part of a bigger sample of 36 patients and 30 controls, who were prospectively enrolled at a single university hospital center and were examined in detail in previous studies 25 , 27 . Only unilateral and histopathologically proven gliomas were finally included in the analysis.…”

“…MRI examination was applied using a 3T Siemens Prisma MRI scanner equipped with a standard 20-channel head coil. The detailed scanning protocol is described in previous studies 25 , 27 , and comprised the following pulse sequences: First, a sagittal 3D T1 magnetization-prepared rapid acquisition gradient echo (MPRAGE) sequence was acquired [repetition time (TR) = 2300 ms, echo time (TE) = 2.01 ms, 176 slices with a slice thickness of 1 mm, flip angle = 9°, field of view (FoV) = 256 mm, voxel size = 1 mm isotropic, and 256 × 256 matrix]. For tumor identification purposes, a contrast-enhanced, T1-weighted turbo inversion recovery magnitude (TIRM) dark-fluid sequence was acquired (TR = 2200 ms, TE = 32 ms, slice thickness = 3 mm, flip angle = 150°, FOV = 230 mm, voxel size = 0.9 × 0.9 × 3.0 mm3, matrix = 256 × 256) as well as a T2-weighted TIRM dark-fluid scan were applied (TR = 9000 ms, TE = 79 ms, slice thickness = 3 mm, flip angle = 150°, FOV = 230 mm, voxel size = 0.9 × 0.9 × 3 mm3, matrix = 256 × 256).…”

“…Previous studies have frequently shown correlations of functional impairment with network-specific alterations in rs-fMRI connectivity in glioma patients 21 , 23 , 24 . Findings did however not always seem conclusive, as increases as well as decreases in network-specific FC have been reported to be associated with functional impairment in patients 9 , 23 , 25 , and the relation to underlying structural alterations remains unclear. Glioma-associated aberrations in whole-brain FC have recently been shown to be associated with tumor grade and isodehydrogenase (IDH) mutation status, with stronger abnormalities described in the prognostically less favorable IDH-wildtype (IDHwt) patient group 26 .…”

Contralesional functional network reorganization of the insular cortex in diffuse low-grade glioma patients

“…These atypical increasing FC only reflected a functional adaption in a short-term but not indicated functional compensation 34 . Even some abnormal increasing FCs were related to worse cognitive performance in patients with glioma 35 . Moreover, some studies found that these increasing FC did not ultimately aid in cognitive function [36][37][38] .…”

Machine Learning Analytics of Resting-State Functional Connectivity Predicts Survival Outcomes of Glioblastoma Multiforme Patients

“…Here we demonstrate that a trained SVM predicts short and long-term survival in GBM patients based on rsFC measures. Previous work in GBM patients have shown that cognitive impairment in GBM patients can be associated with both increases and decreases in rsFC ( 53 , 54 ).…”