What question did this study set out to answer?

This analysis aims to distinguish between different types of brain tumors based on their network perturbations as measured by Fiedler lambda2.

June 2, 2026Open Access

Fiedler Lambda2 Algebraic Connectivity Differentiates Extra-Axial Compression from Intra-Axial Infiltration in Brain Tumors: A Complete 33-Subject rs-fMRI Analysis (ds001226)

Key Points

This analysis aims to distinguish between different types of brain tumors based on their network perturbations as measured by Fiedler lambda2.
Analysis of 33 subjects from the ds001226 rs-fMRI dataset including controls, meningiomas, and gliomas.
Computation of Fiedler lambda2 using Schaefer-100 parcellation and a unified abs(corr) Laplacian pipeline.
Evaluation of lambda2 correlations with tumor size and use of Lo-Shu SE-palace zone energy for spatial discrimination.
Meningioma shows elevated lambda2 (mean=11.46) compared to controls (mean=9.08, AUC=0.706), indicating hyperconnectivity due to compression.
Diffusive gliomas have lambda2 levels similar to controls (mean=9.85, AUC=0.556), showing no significant hyperconnectivity.
Meningioma size significantly correlates with lambda2 (r=0.45), and Lo-Shu energy provides additional spatial distinctions (AUC=0.738).

Abstract

We present a complete analysis of all 33 available subjects from the ds001226 brain tumor rs-fMRI dataset (CON=11, Meningioma=13, Glioma/other=9) using Fiedler lambda2 algebraic connectivity computed from Schaefer-100 parcellation with a unified abs(corr) Laplacian pipeline. The central finding is that lambda2 discriminates the MODE of network perturbation: Meningioma (extra-axial, compressive) shows elevated lambda2 (mean=11.46 vs CON=9.08, AUC=0.706), reflecting compensatory hyperconnectivity driven by mass effect, while diffuse glioma (intra-axial, infiltrative) shows lambda2 indistinguishable from controls (mean=9.85, AUC=0.556). Large high-grade astrocytomas with significant mass effect show paradoxically elevated lambda2, bridging both mechanisms. Meningioma size correlates with lambda2 (r=0.45). Lo-Shu SE-palace zone energy provides complementary spatial discrimination (AUC=0.738). Lambda2 is reframed as a 'compression index' for non-invasive tumor type stratification.

Fiedler Lambda2 Algebraic Connectivity Differentiates Extra-Axial Compression from Intra-Axial Infiltration in Brain Tumors: A Complete 33-Subject rs-fMRI Analysis (ds001226)

Key Points

Abstract

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