Parameter estimation approach to banding artifact reduction in balanced steady-state free precession

Björk, MarcusUppsala universitet,Avdelningen för systemteknik,Reglerteknik,Biomedical systems (författare)

Purpose: The balanced steady-state free precession (bSSFP) pulse sequence has shown to be of great interest due to its high signal-to-noise ratio efficiency. However, bSSFP images often suffer from banding artifacts due to off-resonance effects, which we aim to minimize in this paper. Methods: We present a general and fast two-step algorithm for 1) estimating the unknowns in the bSSFP signal model from multiple phase-cycled acquisitions, and 2) reconstructing band-free images. The first step, Linearization for Off-Resonance Estimation (LORE), solves the nonlinear problem approximately by a robust linear approach. The second step applies a Gauss-Newton algorithm, initialized by LORE, to minimize the nonlinear least squares criterion. We name the full algorithm LORE-GN. Results: We derive the Cramér-Rao bound (CRB), a theoretical lower bound of the variance for any unbiased estimator, and show that LORE-GN is statistically efficient. Furthermore, we show that simultaneous estimation of T1 and T2 from phase-cycled bSSFP is difficult, since the CRB is high at common SNR. Using simulated, phantom, and in vivo data, we illustrate the band-reduction capabilities of LORE-GN compared to other techniques, such as sum-of-squares. Conclusion: Using LORE-GN we can successfully minimize banding artifacts in bSSFP.

Ingle, R. Reeve (författare)
Gudmundson, ErikLund University,Lunds universitet,Matematisk statistik,Matematikcentrum,Institutioner vid LTH,Lunds Tekniska Högskola,Mathematical Statistics,Centre for Mathematical Sciences,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)mats-egn (författare)
Stoica, PeterUppsala universitet,Avdelningen för systemteknik,Reglerteknik,Biomedical systems(Swepub:uu)pst23965 (författare)
Nishimura, Dwight G. (författare)
Barral, Joelle K. (författare)
Uppsala universitetAvdelningen för systemteknik (creator_code:org_t)

Av författaren/redakt...: Björk, Marcus; Ingle, R. Reeve; Gudmundson, Erik; Stoica, Peter; Nishimura, Dwigh ...; Barral, Joelle K ...

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