Details

Autor(en) / Beteiligte

• Dimov, Alexey V.
• Nguyen, Thanh D.
• Gillen, Kelly M.
• Marcille, Melanie
• Spincemaille, Pascal
• Pitt, David
• Gauthier, Susan A.
• Wang, Yi

Titel

Susceptibility source separation from gradient echo data using magnitude decay modeling

Ist Teil von

• Journal of neuroimaging, 2022-09, Vol.32 (5), p.852-859

Ort / Verlag

United States: Wiley Subscription Services, Inc

Erscheinungsjahr

2022

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Background and Purpose The objective is to demonstrate feasibility of separating magnetic sources in quantitative susceptibility mapping (QSM) by incorporating magnitude decay rates R2∗$R_2^{\rm{*}}$ in gradient echo (GRE) MRI. Methods Magnetic susceptibility source separation was developed using R2∗$R_2^{\rm{*}}$ and compared with a prior method using R2′=R2∗−R2${R^{\prime}_2} = R_2^* - {R_2}$ that required an additional sequence to measure the transverse relaxation rate R2. Both susceptibility separation methods were compared in multiple sclerosis (MS) patients (n = 17). Susceptibility values of negative sources estimated with R2∗$R_2^{\rm{*}}$‐based source separation in a set of enhancing MS lesions (n = 44) were correlated against longitudinal myelin water fraction (MWF) changes. Results In in vivo data, linear regression of the estimated χ+${\chi}^{+}$ and χ−${\chi}^{-}$ susceptibility values between the R2∗$R_2^*$‐ and the R2′${R^{\prime}_2}$‐based separation methods performed across 182 segmented lesions revealed correlation coefficient r = .96 and slope close .99. Correlation analysis in enhancing lesions revealed a significant positive association between the χ−${\chi}^{-}$ increase at 1‐year post‐onset relative to 0 year and the MWF increase at 1 year relative to 0 year (β = ‐0.144, 95% confidence interval: [–0.199, –0.1], p = .0008) and good agreement between R2′${R^{\prime}_2}$ and R2∗$R_2^*$ methods (r = .79, slope = .95). Conclusions Separation of magnetic sources based solely on GRE complex data is feasible by combining magnitude decay rate modeling and phase‐based QSM and χ−${\chi}^{-}$ change may serve as a biomarker for myelin recovery or damage in acute MS lesions.