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REPAIRit: Improving Myocardial Nulling and Ghosting Artifacts of 3D Navigator‐Gated Late Gadolinium Enhancement Imaging During Arrhythmia
Author(s) -
Hu Chenxi,
Huber Steffen,
Latif Syed R.,
SantacanaLaffitte Guido,
Mojibian Hamid R.,
Baldassarre Lauren A.,
Peters Dana C.
Publication year - 2019
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.26284
Subject(s) - ghosting , wilcoxon signed rank test , medicine , image quality , imaging phantom , nuclear medicine , signal to noise ratio (imaging) , steady state free precession imaging , cardiology , radiology , magnetic resonance imaging , mann–whitney u test , computer science , mathematics , artificial intelligence , statistics , image (mathematics)
Background Cardiac 3D navigator‐gated late gadolinium enhancement (LGE) imaging is important for assessment of left atrial fibrosis, but the image quality is often degraded due to arrhythmia. Purpose To investigate a novel 3D LGE sequence with improved myocardial nulling and reduced ghosting artifacts during arrhythmia. Study Type Prospective. Population Arrhythmia patients ( n = 14). Sequence The proposed technique, REPAIRit (Regrowth Equalization Pulse for Arrhythmias in Inversion Recovery with automatic i nversion t ime calculation), inserts a saturation pulse with a dynamic flip angle into the 3D LGE sequence to minimize arrhythmia‐induced signal fluctuations. Using ShMOLLI (shortened modified Look–Locker imaging) to estimate myocardial T 1 , REPAIRit automatically calculates the optimal inversion time (TI) based on Bloch equations. Assessment REPAIRit LGE and the standard LGE were compared with simulations, phantom imaging, and patient studies. Patient images were assessed quantitatively, based on ghost‐to‐noise ratio (GNR), blood signal‐to‐noise ratio (SNRb), myocardial signal‐to‐noise ratio (SNRm), and blood‐to‐myocardium contrast‐to‐noise ratio (CNR), and qualitatively on a 4‐point scale. Patients were subgrouped based on the presence of arrhythmia to assess the image quality difference. Statistical Tests The two LGE sequences were compared by Student's t ‐test and Wilcoxon signed‐rank test. The two patient‐subgroups were compared using Welch's t ‐test and Wilcoxon rank‐sum test. Results In 14 analyzed patients, REPAIRit LGE significantly lowered GNR (1.25 ± 0.41 vs. 1.42 ± 0.42, P = 0.04), reduced SNRm (1.90 ± 0.60 vs. 3.16 ± 1.66, P = 0.01), improved ghosting artifact scores (2.5 ± 0.6 vs. 2.2 ± 0.9, P = 0.03), myocardial nulling scores (2.7 ± 0.5 vs. 2.3 ± 0.7, P = 0.02), and atrial quality scores (2.8 ± 0.3 vs. 2.4 ± 0.8, P = 0.03) compared with the standard LGE. Comparing patients with arrhythmia ( n = 6) to those without ( n = 8) during the scan, the former had lower left ventricular (LV) myocardial T 1 s (430 ± 26 msec vs. 469 ± 39 msec, P = 0.06) but similar blood T 1 s (318 ± 55 msec vs. 316 ± 27 msec, P = 0.96), and significantly lower blood SNR (5.2 ± 1.8 vs. 9.2 ± 3.0, P = 0.01) and significantly worse image quality ( P = 0.01 for REPAIRit and P = 0.03 for standard). Data Conclusion REPAIRit improves myocardial nulling and reduces ghosting artifacts of 3D LGE under arrhythmia. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:688–699.