Quote
L. Butry, J. Thomä, J. Forsting, E. Enax-Krumova, and L. Schlaffke, "Cross-vendor reliability of functional and structural brain connectivity in a traveling cohort," Scientific Reports, vol. 16, no. 1, p. 12071, 2026.
Content
Scanner-related bias is a major challenge in multi-center neuroimaging studies. This study assesses cross-vendor reliability of functional and structural brain connectivity (FC, SC) and evaluates the effect of neuroComBat harmonization.A traveling cohort (n = 10) of healthy participants was scanned on a Siemens Prisma 3T and a Philips Achieva 3.0T system within one week. Reliability metrics of FC (Pearson's r) and SC (based on iFOD2 & SIFT2) were calculated for each edge before and after neuroComBat harmonization.At the subject-level, reliability was poor for FC (ICC: 0.22 ± 0.23, wsCV: 62 ± 14%, unharmonized) and fair for SC (ICC: 0.43 ± 0.32, wsCV: 28 ± 15%, unharmonized).At the group-level, Bland-Altman analyses showed minimal systematic bias between scanners in both modalities, but with wide limits of agreement.Pattern similarity was 0.63 (FC) and 0.98 (SC).G Theory analyses showed the scanner accounted for 11.8% (FC) and 7.9% (SC) of the variance.After harmonization, subject-level reliability only improved marginally, but scanner-dependent variability dropped to 0.8% and 1.1% in FC and SC, respectively.Overall, reliability was higher for SC than FC mirroring their differential temporal stability,for group-averaged than subject-level data, and for fullconnectome organization than for individual edges.NeuroComBat worked as designed, successfully mitigating scanner-dependent variance at the group but not the subject level.