Rethinking tractography and neuroanatomy: does image resolution hold the key?

The structural brain connectome spans multiple length scales with varying complexity, from major commissural, association, and projection pathways down to much smaller pathways within brain regions. Diffusion MRI is often acquired for whole-brain coverage with limited spatial resolution for tractography purposes. How does this 'one size fits all' approach impact tractography and diffusion quantification, and do we need to care? Here, we discuss the concept of image resolution and define the structural image resolution limit, representing the resolution threshold at which a given dMRI setup can reliably resolve anatomical structures.