eprintid: 10041770 rev_number: 39 eprint_status: archive userid: 608 dir: disk0/10/04/17/70 datestamp: 2018-01-26 16:02:43 lastmod: 2021-12-19 00:00:11 status_changed: 2018-03-09 11:09:37 type: article metadata_visibility: show creators_name: Milovic, C creators_name: Bilgic, B creators_name: Zhao, B creators_name: Acosta-Cabronero, J creators_name: Tejos, C title: Fast nonlinear susceptibility inversion with variational regularization ispublished: pub divisions: UCL divisions: B02 divisions: C07 divisions: B04 divisions: C05 divisions: F42 keywords: Augmented Lagrangian, nonlinear inversion, quantitative susceptibility mapping, total variation note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: PURPOSE: Quantitative susceptibility mapping can be performed through the minimization of a function consisting of data fidelity and regularization terms. For data consistency, a Gaussian-phase noise distribution is often assumed, which breaks down when the signal-to-noise ratio is low. A previously proposed alternative is to use a nonlinear data fidelity term, which reduces streaking artifacts, mitigates noise amplification, and results in more accurate susceptibility estimates. We hereby present a novel algorithm that solves the nonlinear functional while achieving computation speeds comparable to those for a linear formulation. METHODS: We developed a nonlinear quantitative susceptibility mapping algorithm (fast nonlinear susceptibility inversion) based on the variable splitting and alternating direction method of multipliers, in which the problem is split into simpler subproblems with closed-form solutions and a decoupled nonlinear inversion hereby solved with a Newton-Raphson iterative procedure. Fast nonlinear susceptibility inversion performance was assessed using numerical phantom and in vivo experiments, and was compared against the nonlinear morphology-enabled dipole inversion method. RESULTS: Fast nonlinear susceptibility inversion achieves similar accuracy to nonlinear morphology-enabled dipole inversion but with significantly improved computational efficiency. CONCLUSION: The proposed method enables accurate reconstructions in a fraction of the time required by state-of-the-art quantitative susceptibility mapping methods. Magn Reson Med, 2018. © 2018 International Society for Magnetic Resonance in Medicine. date: 2018-08 date_type: published official_url: http://dx.doi.org/10.1002/mrm.27073 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_id: 1525587 doi: 10.1002/mrm.27073 lyricists_name: Acosta-Cabronero, Julio lyricists_name: Milovic, Carlos lyricists_id: JACOS66 lyricists_id: CMILO93 actors_name: Acosta-Cabronero, Julio actors_id: JACOS66 actors_role: owner full_text_status: public publication: Magnetic Resonance in Medicine volume: 80 number: 2 pagerange: 814-821 event_location: United States issn: 1522-2594 citation: Milovic, C; Bilgic, B; Zhao, B; Acosta-Cabronero, J; Tejos, C; (2018) Fast nonlinear susceptibility inversion with variational regularization. Magnetic Resonance in Medicine , 80 (2) pp. 814-821. 10.1002/mrm.27073 <https://doi.org/10.1002/mrm.27073>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10041770/1/Milovic_Fast_nonlinear_susceptibility.pdf