Daniel Nunes1, Tomás Cruz1, Sune Nørhøj Jespersen2, and Noam Shemesh1
1Champalimaud Neuroscience Program, Champalimaud Center for the Unknown, Lisbon, Portugal, 2CFIN/MindLab, Aarhus Universitet, Århus C, Denmark
Characterizing white matter (WM) microstructure in terms of axon size and volume fraction remains elusive and typically requires extremely strong gradients to resolve water diffusion in micron-sized axons. Here, we develop and apply a new approach for quantifying WM microstructure using a simple multi-gradient-echo (MGE) sequence. We use rat spinal cord as our experimental system, and show that, at long echo times, oscillations in the signal decay emerge, which can be used to robustly quantify the WM microstructure. The ensuing parameteric maps segment the SC into its underlying microstructures. The simplicity of the approach bodes well for many future applications.
