Schweser, F., Sommer, K., Deistung, A., & Reichenbach, J. (2011). Improved Quantitative Susceptibility Mapping ( QSM ) with HEIDI.
Schweser, F., K. Sommer, A. Deistung, and J. Reichenbach. “Improved Quantitative Susceptibility Mapping ( QSM ) with HEIDI” (2011).
Schweser, F., et al. Improved Quantitative Susceptibility Mapping ( QSM ) with HEIDI. 2011.
INTRODUCTION – Quantitative susceptibility mapping (QSM) is a novel imaging technique that determines tissue magnetic susceptibility from the phase of complex gradient-echo (GRE) data . Due to the ill-posed nature of this inverse problem, regularization strategies are required to reduce streaking artifacts on the computed susceptibility maps. It has, for example, been proposed recently to incorporate edge information from GRE magnitude images into the inversion procedure [2,3]. Wharton and Bowtell  have, however, demonstrated that edge information may lead to artificial structures in susceptibility maps. This paper presents an improved QSM algorithm, Homogeneity Enabled Incremental Dipole Inversion (HEIDI), which utilizes a sophisticated problem-specific incremental inversion procedure and a priori information on the homogeneity of the susceptibility distribution rather than on its edges. MATERIALS AND METHODS – A priori information: Extraction of a priori information was based on the assumption that a small gradient of the background-corrected GRE phase images φ coincides with a small gradient of the magnetic susceptibility χ : z y x j j j , , , 0 0 = ≈ ∂ ⇒ ≈ ∂ χ φ . This assumption allows generating a binary mask M of