Subtraction artifacts and frequency (mis-)alignment in J-difference GABA editing.

摘要: Purpose: To compare the repeatability of γ-aminobutyric acid (GABA) measurements using J-difference editing, before and after spectral realignment—a technique which has previously been demonstrated to improve quality GABA spectra. Materials Methods: We performed in vivo three brain regions (occipital, sensorimotor, dorsolateral prefrontal cortex [DLPFC]), analyzed these alternative alignment approaches evaluate impact on repeatability: “Independent alignment” (aligning each subspectrum independently) “Pairwise off as a pair) were compared. Results: Pairwise improved group mean coefficient variation all regions; 0.4% occipital, 1.1% DLPFC. Independent resulted subtraction artifacts majority cases, increased DLPFC by 9.4%. Simulations demonstrate that quantification error datasets with high B0 drift, is 4.5% without alignment, but <1% optimal alignment. Conclusion: Pairwise improves spectroscopy data. However, independently aligning subspectra can lead worse when compared nonaligned J. Magn. Reson. Imaging 2013;. © 2013 Wiley Periodicals, Inc.