BACKGROUND Robust and homogeneous lipid suppression is mandatory for coronary artery cardiovascular magnetic resonance (CMR) imaging since the coronary arteries are commonly embedded in epicardial fat. However, effective large volume lipid suppression becomes more challenging when performing radial whole-heart coronary artery CMR for respiratory self-navigation and the problem may even be exacerbated at increasing magnetic field strengths. Incomplete fat suppression not only hinders a correct visualization of the coronary vessels and generates image artifacts, but may also affect advanced motion correction methods. The aim of this study was to evaluate a recently reported lipid insensitive CMR method when applied to a noncontrast self-navigated coronary artery CMR acquisitions at 3 T, and to compare it to more conventional fat suppression techniques. METHODS Lipid insensitive binomial off resonant excitation (LIBRE) radiofrequency excitation pulses were included into a self-navigated 3D radial GRE coronary artery CMR sequence at 3 T. LIBRE was compared against a conventional CHESS fat saturation (FS) and a binomial 1-180°-1 water excitation (WE) pulse. First, fat suppression of all techniques was numerically characterized using Matlab and experimentally validated in phantoms and in legs of human volunteers. Subsequently, free-breathing self-navigated coronary artery CMR was performed using the LIBRE pulse as well as FS and WE in ten healthy subjects. Myocardial, arterial and chest fat signal-to-noise ratios (SNR), as well as coronary vessel conspicuity were quantitatively compared among those scans. RESULTS The results obtained in the simulations were confirmed by the experimental validations as LIBRE enabled near complete fat suppression for 3D radial imaging in vitro and in vivo. For self-navigated whole-heart coronary artery CMR at 3 T, fat SNR was significantly attenuated using LIBRE compared with conventional FS. LIBRE increased the right coronary artery (RCA) vessel sharpness significantly (37 ± 9% (LIBRE) vs. 29 ± 8% (FS) and 30 ± 8% (WE), both p < 0.05) and led to a significant increase in the measured RCA vessel length to (83 ± 31 mm (LIBRE) vs. 56 ± 12 mm (FS) and 59 ± 27 (WE) p < 0.05). CONCLUSIONS Applied to a respiratory self-navigated noncontrast 3D radial whole-heart sequence, LIBRE enables robust large volume fat suppression and significantly improves coronary artery image quality at 3 T compared to the use of conventional FS and WE.

中文翻译：

---

使用脂质不敏感的二项式非共振激发（LIBRE），在3 T时进行无对比度的自由呼吸呼吸自主导航冠状动脉心血管磁共振血管造影。

背景技术由于冠状动脉通常嵌在心外膜脂肪中，因此坚固而均质的脂质抑制对于冠状动脉心血管磁共振（CMR）成像是必不可少的。然而，当进行放射状全心冠状动脉CMR进行呼吸自导航时，有效的大剂量脂质抑制变得更具挑战性，并且在磁场强度增加的情况下甚至可能加剧该问题。不完全的脂肪抑制不仅会妨碍冠状血管的正确可视化并产生图像伪影，而且可能会影响高级的运动校正方法。这项研究的目的是评估一种最近报道的对3T时无造影剂自导航冠状动脉CMR采集的脂质不敏感CMR方法，并将其与更常规的脂肪抑制技术进行比较。方法将脂质不敏感的二项式离共振激发（LIBRE）射频激发脉冲纳入3 T的自导航3D径向GRE冠状动脉CMR序列中。将LIBRE与常规CHESS脂肪饱和度（FS）和二项式1-180°进行比较-1水激发（WE）脉冲。首先，使用Matlab对所有技术的脂肪抑制进行了数值表征，并在人体志愿者的幻影和腿部进行了实验验证。随后，使用LIBRE脉冲以及FS和WE对十名健康受试者进行了自主呼吸的自主导航冠状动脉CMR。在这些扫描中，定量比较了心肌，动脉和胸部脂肪的信噪比（SNR）以及冠状动脉的显着性。结果在模拟中获得的结果通过实验验证得到了证实，因为LIBRE能够在体外和体内对3D径向成像进行几乎完全的脂肪抑制。对于3 T时自导航的全心脏冠状动脉CMR，与常规FS相比，使用LIBRE可使脂肪SNR显着衰减。LIBRE显着提高了右冠状动脉（RCA）血管的清晰度（37±9％（LIBRE）与29±8％（FS）和30±8％（WE），均p <0.05），并导致右冠状动脉的锐度增加测量的RCA血管长度为（83±31 mm（LIBRE）与56±12 mm（FS）和59±27（WE）p <0.05）。结论适用于呼吸自导航非对比3D放射状全心序列，