Designing long-T2 suppression pulses for ultrashort echo time imaging
Designing long-T2 suppression pulses for ultrashort echo time imaging
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DOI：
10.1002/mrm.20926
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发表时间：
2006-07-01
影响因子：
3.3
通讯作者：
Nishimura, Dwight G.
中科院分区：
文献类型：
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作者：
Larson, Peder E. Z.;Gurney, Paul T.;Nishimura, Dwight G.
超短回波时间 (UTE) 成像已显示出作为一种 T-2 值为几毫秒或更短的组织成像技术的前景。这些组织，如肌腱、半月板和皮质骨，在传统磁共振成像技术中通常是不可见的，但在 LITE 成像中却有信号。它们很难可视化，因为它们经常被具有较长 T-2 值的组织遮挡。在本文中，介绍了新的长 T-2 抑制 RF 脉冲，可提高短 T-2 物种的对比度。这些脉冲比以前的长 T-2 抑制脉冲有所改进，以前的长 T-2 抑制脉冲的偏共振特性或 T-2 灵敏度较差。在某些应用中，短 T-2 组织对比度也可以通过抑制脂肪来改善。还引入了额外抑制脂肪的双波段长 T-2 抑制脉冲。模拟以及使用 2D 和 3D LITE 成像的体模和体内实验证明了这些新型长 T-2 抑制脉冲的可行性、改进的对比度和改进的灵敏度。所得图像主要显示短 T-2 物种，而大多数长 T-2 物种受到抑制。
Ultrashort echo time (UTE) imaging has shown promise as a technique for imaging tissues with T-2 values of a few milliseconds or less. These tissues, such as tendons, menisci, and cortical bone, are normally invisible in conventional magnetic resonance imaging techniques but have signal in LITE imaging. They are difficult to visualize because they are often obscured by tissues with longer T-2 values. In this article, new long-T-2 suppression RF pulses that improve the contrast of short-T-2 species are introduced. These pulses are improvements over previous long-T-2 suppression pulses that suffered from poor off-resonance characteristics or T-2, sensitivity. Short-T-2 tissue contrast can also be improved by suppressing fat in some applications. Dual-band long-T-2 suppression pulses that additionally suppress fat are also introduced. Simulations, along with phantom and in vivo experiments using 2D and 3D LITE imaging, demonstrate the feasibility, improved contrast, and improved sensitivity of these new long-T-2 suppression pulses. The resulting images show predominantly short-T-2 species, while most long-T-2 species are suppressed.