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Simultaneous acquisition of image and navigator slices using CAIPIRINHA for 4D MRI
Author(s) -
Celicanin Zarko,
Bieri Oliver,
Preiswerk Frank,
Cattin Philippe,
Scheffler Klaus,
Santini Francesco
Publication year - 2015
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.25134
Subject(s) - imaging phantom , image quality , computer science , artificial intelligence , computer vision , real time mri , iterative reconstruction , signal (programming language) , temporal resolution , noise (video) , magnetic resonance imaging , nuclear medicine , image (mathematics) , physics , medicine , radiology , optics , programming language
Purpose Respiratory organ motion is still the major challenge of various image‐guided treatments in the abdomen. Dynamic organ motion tracking, necessary for the treatment control, can be performed with volumetric time‐resolved MRI that sequentially acquires one image and one navigator slice. Here, a novel imaging method is proposed for truly simultaneous high temporal resolution acquisition. Methods A standard balanced steady state free precession sequence was modified to simultaneously acquire two superimposed slices with different phase cycles, namely an image and a navigator slice. Instead of multiband RF pulses, two separate RF pulses were used for the excitation. Images were reconstructed using offline CAIPIRINHA reconstruction. Phantom and in vivo measurements of healthy volunteers were performed and evaluated. Results Phantom and in vivo measurements showed good image quality with high signal‐to‐noise ratio (SNR) and no reconstruction issues. Conclusion We present a novel imaging method for truly simultaneous acquisition of image and navigator slices for four‐dimensional (4D) MRI of organ motion. In this method, the time lag between the sequential acquisitions is eliminated, leading to an improved accuracy of organ motion models, while CAIPIRINHA reconstruction results in an improved SNR compared with an existing 4D MRI approach. Magn Reson Med 73:669–676, 2015. © 2014 Wiley Periodicals, Inc.