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Accelerated slice encoding for metal artifact correction
Author(s) -
Hargreaves Brian A.,
Chen Weitian,
Lu Wenmiao,
Alley Marcus T.,
Gold Garry E.,
Brau Anja C.S.,
Pauly John M.,
Pauly Kim Butts
Publication year - 2010
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22112
Subject(s) - artifact (error) , spin echo , computer science , signal (programming language) , biomedical engineering , materials science , magnetic resonance imaging , computer vision , medicine , radiology , programming language
Purpose: To demonstrate accelerated imaging with both artifact reduction and different contrast mechanisms near metallic implants. Materials and Methods: Slice‐encoding for metal artifact correction (SEMAC) is a modified spin echo sequence that uses view‐angle tilting and slice‐direction phase encoding to correct both in‐plane and through‐plane artifacts. Standard spin echo trains and short‐TI inversion recovery (STIR) allow efficient PD‐weighted imaging with optional fat suppression. A completely linear reconstruction allows incorporation of parallel imaging and partial Fourier imaging. The signal‐to‐noise ratio (SNR) effects of all reconstructions were quantified in one subject. Ten subjects with different metallic implants were scanned using SEMAC protocols, all with scan times below 11 minutes, as well as with standard spin echo methods. Results: The SNR using standard acceleration techniques is unaffected by the linear SEMAC reconstruction. In all cases with implants, accelerated SEMAC significantly reduced artifacts compared with standard imaging techniques, with no additional artifacts from acceleration techniques. The use of different contrast mechanisms allowed differentiation of fluid from other structures in several subjects. Conclusion: SEMAC imaging can be combined with standard echo‐train imaging, parallel imaging, partial‐Fourier imaging, and inversion recovery techniques to offer flexible image contrast with a dramatic reduction of metal‐induced artifacts in scan times under 11 minutes. J. Magn. Reson. Imaging 2010;31:987–996. ©2010 Wiley‐Liss, Inc.