Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, North Carolina, USA.
Magn Reson Med. 2013 Nov;70(5):1360-8. doi: 10.1002/mrm.24564. Epub 2012 Dec 4.
A versatile method for generating T2 -weighting is a T2 -preparation module, which has been used successfully for cardiac imaging at 1.5T. Although it has been applied at 3T, higher fields (B0 ≥ 3T) can degrade B0 and B1 homogeneity and result in nonuniform magnetization preparation. For cardiac imaging, blood flow and cardiac motion may further impair magnetization preparation. In this study, a novel T2 -preparation module containing multiple adiabatic B1 -insensitive refocusing pulses is introduced and compared with three previously described modules [(a) composite MLEV4, (b) modified BIR-4 (mBIR-4), and (c) Silver-Hoult-pair]. In the static phantom, the proposed module provided similar or better B0 and B1 insensitivity than the other modules. In human subjects (n = 21), quantitative measurement of image signal coefficient of variation, reflecting overall image inhomogeneity, was lower for the proposed module (0.10) than for MLEV4 (0.15, P < 0.0001), mBIR-4 (0.27, P < 0.0001), and Silver-Hoult-pair (0.14, P = 0.001) modules. Similarly, qualitative analysis revealed that the proposed module had the best image quality scores and ranking (both, P < 0.0001). In conclusion, we present a new T2 -preparation module, which is shown to be robust for cardiac imaging at 3T in comparison with existing methods.
一种通用的 T2 加权生成方法是 T2 准备模块,该模块已成功用于 1.5T 心脏成像。尽管它已应用于 3T,但更高的场(B0 ≥ 3T)会降低 B0 和 B1 均匀性,并导致不均匀的磁化准备。对于心脏成像,血流和心脏运动可能会进一步损害磁化准备。在这项研究中,引入了一种包含多个绝热 B1 不敏感重聚焦脉冲的新型 T2 准备模块,并将其与之前描述的三个模块进行了比较[(a)复合 MLEV4,(b)改进的 BIR-4(mBIR-4)和(c)Silver-Hoult 对]。在静态体模中,所提出的模块提供的 B0 和 B1 不敏感性与其他模块相似或更好。在 21 名人类受试者中,反映整体图像不均匀性的图像信号变异系数的定量测量值,所提出的模块(0.10)低于 MLEV4(0.15,P<0.0001)、mBIR-4(0.27,P<0.0001)和 Silver-Hoult 对(0.14,P=0.001)模块。同样,定性分析表明,所提出的模块具有最佳的图像质量评分和排名(均为 P<0.0001)。总之,与现有方法相比,我们提出了一种新的 T2 准备模块,该模块在 3T 心脏成像中表现出很强的稳健性。