Microstructure-Weighted Connectomics: dual-site validation of a diffusion MRI protocol for mapping brain structural connectivity

Motivation: Microstructure-weighted connectomes offer valuable insights into brain pathology mechanisms. To ensure a reliable analysis, diffusion model parameters and connectome metrics must remain consistent across protocols and scanners. Goal(s): This work aimed to validate a four-shell diffusion MRI protocol for structural connectome reconstruction and assess the consistency of the extracted network metrics across acquisitions. Approach: Phantom and in-vivo data were acquired on two 3T scanners and processed with DTI and NODDI models. Connectomes were reconstructed from in-vivo data and modelled as undirected weighted networks. Results: The four-shell protocol yielded stable and consistent fit results. Network metrics from microstructure-weighted connectomes demonstrated good agreement across scanners. Impact: This study demonstrates the reproducibility of microstructure-weighted connectomes, supporting their use in investigating brain connectivity. By integrating detailed microstructural information from advanced models like NODDI, these connectomes offer richer characterisation of brain structures, contributing to improved understanding of brain diseases.