Axcaliber: A method for measuring axon diameter distribution from diffusion MRI

The diameter of a myelinated nerve axon is directly proportional to its conduction velocity, so the axon diameter distribution helps determine the channel capacity of nervous transmission along fascicles in the central (CNS) and peripheral nervous systems (PNS). Previously, this histological information could only be obtained using invasive tissue biopsies. Here we propose a new NMR-based approach that employs a model of water diffusion within "restricted" cylindrical axons to estimate their diameter distribution within a nerve bundle. This approach can be combined with MRI to furnish an estimate of the axon diameter distribution within each voxel. This method is validated by comparing the diameter…

• IS
  Israel Science Foundation
• TA
  Tel Aviv University
• NI
  National Institutes of Health
• NI
  National Institute of Child Health and Human Development