20 May 21. Featured Paper

Link to paper on Human Brain Mapping

Authors

Colin R. Buchanan, Susana Muñoz Maniega, Maria C. Valdés Hernández, Lucia Ballerini, Gayle Barclay, Adele M. Taylor, Tom C. Russ, Elliot M. Tucker-Drob, Joanna M. Wardlaw, Ian J. Deary, Mark E. Bastin, Simon R. Cox

Abstract

Multi-scanner MRI studies are reliant on understanding the apparent differences in imaging measures between different scanners.

We provide a comprehensive analysis of T1-weighted & diffusion MRI (dMRI) structural brain measures between a 1.5 T GE Signa Horizon HDx & a 3 T Siemens Magnetom Prisma using 91 community-dwelling older participants (aged 82 years).

Although we found considerable differences in absolute measurements (global tissue volumes were measured as ~6–11% higher & fractional anisotropy [FA] was 33% higher at 3 T than at 1.5 T), between-scanner consistency was good to excellent for global volumetric & dMRI measures (intraclass correlation coefficient [ICC] range: .612–.993) & fair to good for 68 cortical regions (FreeSurfer) & cortical surface measures (mean ICC: .504–.763).

Between-scanner consistency was fair for dMRI measures of 12 major white matter tracts (mean ICC: .475–.564), & the general factors of these tracts provided excellent consistency (ICC ≥ .769).

Whole-brain structural networks provided good to excellent consistency for global metrics (ICC ≥ .612).

Although consistency was poor for individual network connections (mean ICCs: .275−.280), this was driven by a large difference in network sparsity (.599 vs. .334), & consistency was improved when comparing only the connections present in every participant (mean ICCs: .533–.647).

Regression-based k-fold cross-validation showed that, particularly for global volumes, between-scanner differences could be largely eliminated (R2 range .615–.991).

We conclude that low granularity measures of brain structure can be reliably matched between the scanners tested, but caution is warranted when combining high granularity information from different scanners.

Keywords

• Brain
• Connectome
• Diffusion MRI
• Multi-site
• Reliability
• Structural MRI