Multi-echo segmented k-space imaging: An optimized hybrid sequence for ultrafast cardiac imaging
Multi-echo segmented k-space imaging: An optimized hybrid sequence for ultrafast cardiac imaging
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DOI：
10.1002/(sici)1522-2594(199902)41:2
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发表时间：
1999-02-01
影响因子：
3.3
通讯作者：
McVeigh, ER
中科院分区：
文献类型：
--
作者：
Reeder, SB;Atalar, E;McVeigh, ER
心脏磁共振成像需要高时间分辨率来解决运动和造影剂摄取，同时需要低总扫描时间以避免呼吸伪影。虽然扰相梯度回波（SPGR）成像是鲁棒的和可再现的，但是其相对低效并且需要长时间屏气来获取心脏的高时间分辨率电影。回波平面成像（EPI）具有出色的信噪比（SNR）性能，非常高效;然而，由于其对化学位移、磁化率和运动的敏感性，因此特别难以在心脏中使用。EPI还可能需要参考扫描，用于测量导致重影伪影的硬件延迟和相位偏移;这些参考扫描在心脏中更困难且更不可靠。因此，混合EPI/SPGR序列提出了应用于快速心脏成像。给出了多回波序列信噪比和回波串长度的优化方法。结果表明，显着减少总扫描时间是可能的，同时保持良好的图像质量。这将允许在一到三次屏气中对整个心脏进行完整的运动采样，这是MR心脏多巴酚丁胺负荷测试所必需的。改进的速度性能还允许每次心跳采样三到六个切片用于团注灌注（C）1999 Wiley-Liss，Inc.
Cardiac magnetic resonance imaging requires high temporal resolution to resolve motion and contrast uptake with low total scan times to avoid breathing artifacts. While spoiled gradient echo (SPGR) imaging is robust and reproducible, it is relatively inefficient and requires long breath-holds to acquire high time resolution movies of the heart. Echo planar imaging (EPI) is highly efficient with excellent signal-to-noise ratio (SNR) behavior; however, it is particularly difficult to use in the heart because of its sensitivity to chemical shift, susceptibility, and motion. EPI may also require reference scans, which are used to measure hardware delays and phase offsets that cause ghosting artifacts; these reference scans are more difficult and less reliable in the heart. Consequently, a hybrid EPI/SPGR sequence is proposed for application to rapid cardiac imaging. A detailed optimization of SNR and echo train length for multi-echo sequences is presented. It is shown that significant reductions in total scan time are possible while maintaining good image quality. This will allow complete motion sampling of the entire heart in one to three breath-holds, necessary for MR cardiac dobutamine stress testing. Improved speed performance also permits sampling of three to six slices every heartbeat for bolus injection perfusion (C) 1999 Wiley-Liss, Inc.