Kevin D. Harkins1,2, Adrienne N. Dula1,2,
Mark D. Does, 1,3
1Institute of Image Science, Vanderbilt
University, Nashville, TN, United States; 2Radiology and
Radiological Sciences, Vanderbilt University, Nashville, TN, United States; 3Biomedical
Engineering, Vanderbilt University, Nashville, TN, United States
The
myelin water fraction (MWF) estimated from multi-exponential T2 analysis is
an effective marker of myelin in tissue, but there is evidence that the MWF
is underestimated due to the exchange of water between myelin and other
tissue compartments. In this work, in-vivo experiments confirm a bias in the
MWF within rat spinal cord. Numerical studies further suggest that exchange
can account for the variation in MWF, and that exchange between T2 components
may be limited by the apparent diffusivity of myelin water.