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Investigating the stability of mcDESPOT myelin water fraction values derived using a stochastic region contraction approach
Author(s) -
Deoni Sean C.L.,
Kolind Shan H.
Publication year - 2015
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25108
Subject(s) - parameter space , sensitivity (control systems) , contraction (grammar) , imaging phantom , biological system , range (aeronautics) , mathematics , computer science , mathematical optimization , physics , statistics , materials science , optics , medicine , electronic engineering , engineering , composite material , biology
Purpose Multicomponent driven equilibrium single pulse observation of T 1 and T 2 (mcDESPOT) is an alternative to established multiecho T 2 ‐based approaches for quantifying myelin water fraction, affording increased volumetric coverage and spatial resolution. A concern with mcDESPOT, however, is the large number of model parameters that must be estimated, which may lead to nonunique solutions and sensitivity to fitting constraints. Here we explore mcDESPOT performance under different experimental conditions to better understand the method's sensitivity and reliability. Methods To obtain parameter estimates, mcDESPOT uses a stochastic region contraction (SRC) approach to iteratively contract a predefined solution search‐space around a global optimum. The sensitivity of mcDESPOT estimates to SRC boundary conditions, and tissue parameters, was examined using numerical phantoms and acquired in vivo human data. Results The SRC approach is described and shown to return robust myelin water estimates in both numerical phantoms and in vivo data under a range of experimental conditions. However, care must be taken in choosing the initial SRC boundary conditions, ensuring they are broad enough to encompass the “true” solution. Conclusion Results suggest that under the range of conditions examined, mcDESPOT can provide stabile and precise values. Magn Reson Med 73:161–169, 2015. © 2014 Wiley Periodicals, Inc.