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Multifrequency interpolation for fast off‐resonance correction
Author(s) -
Man LaiChee,
Pauly John M.,
Macovski Albert
Publication year - 1997
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910370523
Subject(s) - interpolation (computer graphics) , imaging phantom , spiral (railway) , projection (relational algebra) , computer science , set (abstract data type) , field (mathematics) , artificial intelligence , algorithm , computer vision , data set , iterative reconstruction , linear interpolation , physics , mathematics , pattern recognition (psychology) , image (mathematics) , optics , mathematical analysis , pure mathematics , programming language
Abstract Field inhomogeneities or susceptibility variations produce blurring in images acquired using non‐2DFT k ‐space readout trajectories. This problem is more pronounced for sequences with long readout times such as spiral imaging. Theoretical and practical correction methods based on an acquired field map have been reported in the past. This paper introduces a new correction method based on the existing concept of frequency segmented correction but which is faster and the‐oretically more accurate. It consists of reconstructing the data at several frequencies to form a set of base images that are then added together with spatially varying linear coefficients derived from the field map. The new algorithm is applied to phantom and in vivo images acquired with projection reconstruction and spiral sequences, yielding sharply focused images.