Electric Field Simulations Show High Reliability Across Multiple MRI Scanners
A traveling-subject neuroimaging study found that individualized electric field simulations for transcranial brain stimulation are highly reliable across different MRI scanners and repeated scans. Researchers scanned 10 participants twice on each of five 3T Siemens scanners, using SimNIBS v4.1 to simulate targeted electrical stimulation across seven brain regions. The findings support the use of these simulations in large-scale, multicenter brain stimulation research.
A preprint study posted to bioRxiv assessed whether electric field simulations used to plan transcranial direct current stimulation (tDCS) remain consistent when MRI data are collected across different scanners or at different time points. Using a traveling-subject design, 10 participants were each scanned twice on five different 3T Siemens MRI scanners, and SimNIBS v4.1 was used to simulate focal tDCS targeting seven cortical and cerebellar regions. Intraclass correlation coefficients (ICC) indicated good to excellent inter-scanner reliability (0.86–0.97) and scan-rescan reliability (0.94–0.98), with between-scanner variance not exceeding typical measurement error. The primary driver of within-person variability in simulated field magnitudes was intra-individual segmentation variability — differences in how the software parsed brain anatomy across scans — rather than image quality metrics. These results address a longstanding gap in the neuroimaging reliability literature, where structural, functional, and diffusion MRI had been validated for multicenter use but electric field simulations had not. The authors conclude that individualized electric field models are robust to scanner-related variation, strengthening the case for pooling data across sites in brain stimulation research.
What's missing
The study used only 3T Siemens scanners, leaving open whether findings generalize to other field strengths (e.g., 7T) or scanner manufacturers (e.g., GE, Philips). The sample size of 10 participants is small, and the study does not address whether reliability holds across clinical populations with atypical brain anatomy. The relationship between simulation reliability and actual clinical or behavioral outcomes from tDCS is not examined.
What different sources said
- bioRxivCenter
Multicenter reliability of electric field simulations: Evidence from a traveling-subjects study
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