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Inflow artifact reduction using an adaptive flip‐angle navigator restore pulse for late gadolinium enhancement of the left atrium
Author(s) -
Henningsson Markus,
Carlhäll CarlJohan
Publication year - 2020
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.28334
Subject(s) - flip angle , artifact (error) , pulse (music) , magnetic resonance imaging , nuclear medicine , medicine , pulmonary vein , computer science , cardiology , radiology , atrial fibrillation , computer vision , telecommunications , detector
Purpose Late gadolinium enhancement (LGE) of the left atrium is susceptible to artifacts arising from the right pulmonary veins, caused by inflowing blood tagged by the navigator restore pulse. The purpose of this study was to evaluate a new method to reduce the inflow artifact using an adaptive flip‐angle restore pulse. Methods A low‐restore angle reduces the inflow artifact but may lead to a poor navigator SNR. The proposed approach aims to determine the patient‐specific restore angle, which optimizes the trade‐off between inflow artifacts and navigator SNR. Three‐dimensional LGE with adaptive navigator restore (3D LGE A ) was implemented by incrementing the flip angle of the restore pulse from a starting value of 0°, based on the navigator normalized cross‐correlation. Magnetic resonance imaging experiments were performed on a 1.5T scanner. The value of 3D LGE A was compared with 3D LGE with a constant 180° restore pulse (3D LGE 180 ) in 22 patients with heart diseases. The values of 3D LGE A and 3D LGE 180 were compared in terms of pulmonary vein blood signal relative to reference blood in the descending aorta (PV rel ) and visual scoring to determine level of motion artifacts using a 4‐point scale (1 = severe artifacts; 4 = no artifacts). Results The value of PV rel was significantly lower for 3D LGE A than for 3D LGE 180 (1.16 ± 0.23 vs. 1.59 ± 0.29, P < .001). Furthermore, visual scoring of the motion artifacts yielded no difference ( P = .78). Conclusion Adaptively adjusting the navigator restore flip angle based on the navigator normalized cross‐correlation reduces the 3D LGE inflow artifact without affecting image quality or the scan time.