Department of Diagnostic and Interventional Radiology, University Hospital Saarland, Homburg, Germany.
Invest Radiol. 2009 Dec;44(12):757-62. doi: 10.1097/RLI.0b013e3181bfe36c.
To compare 3 different flow targeted magnetization preparation strategies for coronary MR angiography (cMRA), which allow selective visualization of the vessel lumen.
The right coronary artery of 10 healthy subjects was investigated on a 1.5 Tesla MR system (Gyroscan ACS-NT, Philips Healthcare, Best, NL). A navigator-gated and ECG-triggered 3D radial steady-state free-precession (SSFP) cMRA sequence with 3 different magnetization preparation schemes was performed referred to as projection SSFP (selective labeling of the aorta, subtraction of 2 data sets), LoReIn SSFP (double-inversion preparation, selective labeling of the aorta, 1 data set), and inflow SSFP (inversion preparation, selective labeling of the coronary artery, 1 data set). Signal-to-noise ratio (SNR) of the coronary artery and aorta, contrast-to-noise ratio (CNR) between the coronary artery and epicardial fat, vessel length and vessel sharpness were analyzed.
All cMRA sequences were successfully obtained in all subjects. Both projection SSFP and LoReIn SSFP allowed for selective visualization of the coronary arteries with excellent background suppression. Scan time was doubled in projection SSFP because of the need for subtraction of 2 data sets. In inflow SSFP, background suppression was limited to the tissue included in the inversion volume. Projection SSFP (SNR(coro): 25.6 +/- 12.1; SNR(ao): 26.1 +/- 16.8; CNR(coro-fat): 22.0 +/- 11.7) and inflow SSFP (SNR(coro): 27.9 +/- 5.4; SNR(ao): 37.4 +/- 9.2; CNR(coro-fat): 24.9 +/- 4.8) yielded significantly increased SNR and CNR compared with LoReIn SSFP (SNR(coro): 12.3 +/- 5.4; SNR(ao): 11.8 +/- 5.8; CNR(coro-fat): 9.8 +/- 5.5; P < 0.05 for both). Longest visible vessel length was found with projection SSFP (79.5 mm +/- 18.9; P < 0.05 vs. LoReIn) whereas vessel sharpness was best in inflow SSFP (68.2% +/- 4.5%; P < 0.05 vs. LoReIn). Consistently good image quality was achieved using inflow SSFP likely because of the simple planning procedure and short scanning time.
Three flow targeted cMRA approaches are presented, which provide selective visualization of the coronary vessel lumen and in addition blood flow information without the need of contrast agent administration. Inflow SSFP yielded highest SNR, CNR and vessel sharpness and may prove useful as a fast and efficient approach for assessing proximal and mid vessel coronary blood flow, whereas requiring less planning skills than projection SSFP or LoReIn SSFP.
比较 3 种不同的流动靶向磁化准备策略用于冠状动脉磁共振血管造影（cMRA），可选择性地显示血管管腔。
在 1.5T 磁共振系统（Gyroscan ACS-NT，飞利浦医疗保健，Best，NL）上对 10 名健康受试者的右冠状动脉进行了研究。使用 3 种不同的磁化准备方案的导航门控和 ECG 触发的 3D 径向稳态自由进动（SSFP）cMRA 序列，分别称为投影 SSFP（主动脉选择性标记，2 个数据集相减）、LoReIn SSFP（双反转准备，主动脉选择性标记，1 个数据集）和流入 SSFP（反转准备，冠状动脉选择性标记，1 个数据集）。分析冠状动脉和主动脉的信噪比（SNR）、冠状动脉和心外膜脂肪之间的对比噪声比（CNR）、血管长度和血管锐利度。
所有 cMRA 序列均在所有受试者中成功获得。投影 SSFP 和 LoReIn SSFP 均允许选择性地可视化冠状动脉，具有出色的背景抑制。由于需要减去 2 个数据集，因此投影 SSFP 的扫描时间增加了一倍。在流入 SSFP 中，背景抑制仅限于反转体积中包含的组织。与 LoReIn SSFP 相比，投影 SSFP（SNR（coro）：25.6 ± 12.1；SNR（ao）：26.1 ± 16.8；CNR（coro-fat）：22.0 ± 11.7）和流入 SSFP（SNR（coro）：27.9 ± 5.4；SNR（ao）：37.4 ± 9.2；CNR（coro-fat）：24.9 ± 4.8）产生了显著增加的 SNR 和 CNR（P < 0.05）。投影 SSFP 获得最长的可见血管长度（79.5mm ± 18.9；P < 0.05 与 LoReIn），而流入 SSFP 的血管锐利度最佳（68.2% ± 4.5%；P < 0.05 与 LoReIn）。流入 SSFP 始终能获得良好的图像质量，这可能是由于其简单的规划程序和较短的扫描时间。
提出了 3 种流动靶向 cMRA 方法，可提供冠状动脉管腔的选择性可视化以及血流信息，而无需使用造影剂。流入 SSFP 产生了最高的 SNR、CNR 和血管锐利度，可能作为评估近端和中段冠状动脉血流的快速有效的方法，而比投影 SSFP 或 LoReIn SSFP 需要更少的规划技能。
