Comparison of spoiled gradient echo and steady‐state free‐precession imaging for native myocardial T1 mapping using the slice‐interleaved T1 mapping (STONE) sequence |
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| Authors: | Jihye Jang Steven Bellm Sébastien Roujol Tamer A. Basha Maryam Nezafat Shingo Kato Sebastian Weingärtner Reza Nezafat |
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| Affiliation: | 1. Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA;2. Department of Computer Science, Technical University of Munich, Munich, Germany;3. Biomedical Engineering Department, Cairo University, Giza, Egypt;4. Division of Imaging Sciences & Biomedical Engineering, King's College London, London, UK;5. Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany |
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| Abstract: | Cardiac T1 mapping allows non‐invasive imaging of interstitial diffuse fibrosis. Myocardial T1 is commonly calculated by voxel‐wise fitting of the images acquired using balanced steady‐state free precession (SSFP) after an inversion pulse. However, SSFP imaging is sensitive to B1 and B0 imperfection, which may result in additional artifacts. A gradient echo (GRE) imaging sequence has been used for myocardial T1 mapping; however, its use has been limited to higher magnetic field to compensate for the lower signal‐to‐noise ratio (SNR) of GRE versus SSFP imaging. A slice‐interleaved T1 mapping (STONE) sequence with SSFP readout (STONE–SSFP) has been recently proposed for native myocardial T1 mapping, which allows longer recovery of magnetization (>8 R–R) after each inversion pulse. In this study, we hypothesize that a longer recovery allows higher SNR and enables native myocardial T1 mapping using STONE with GRE imaging readout (STONE–GRE) at 1.5T. Numerical simulations and phantom and in vivo imaging were performed to compare the performance of STONE–GRE and STONE–SSFP for native myocardial T1 mapping at 1.5T. In numerical simulations, STONE–SSFP shows sensitivity to both T2 and off resonance. Despite the insensitivity of GRE imaging to T2, STONE–GRE remains sensitive to T2 due to the dependence of the inversion pulse performance on T2. In the phantom study, STONE–GRE had inferior accuracy and precision and similar repeatability as compared with STONE–SSFP. In in vivo studies, STONE–GRE and STONE–SSFP had similar myocardial native T1 times, precisions, repeatabilities and subjective T1 map qualities. Despite the lower SNR of the GRE imaging readout compared with SSFP, STONE–GRE provides similar native myocardial T1 measurements, precision, repeatability, and subjective image quality when compared with STONE–SSFP at 1.5T. |
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| Keywords: | balanced steady‐state free precession cardiovascular MR (CMR) methods myocardial T1 mapping relaxometry slice‐interleaved T1 mapping spoiled gradient echo |
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