Department of Radiology, University of California, San Diego, California, USA.
GE Healthcare, San Diego, California, USA.
Magn Reson Med. 2018 May;79(5):2555-2563. doi: 10.1002/mrm.26908. Epub 2017 Sep 14.
To investigate high contrast imaging of short T tissues with a three-dimensional double adiabatic inversion recovery prepared ultrashort echo time Cones (3D DIR-UTE-Cones) sequence.
The sequence used two sequential adiabatic inversion pulses to suppress signals from long T tissues, followed by multispoke UTE acquisition to detect signals from short T tissues. The two adiabatic inversion pulses are identical with a center frequency located at the water peak, but the spectral width is broad enough to cover both water and fat frequencies. The feasibility of this technique was demonstrated through numerical simulation and phantom studies. Finally, DIR-UTE-Cones was applied to three healthy volunteers to image cortical bone, patellar tendon, and Achilles tendon. T2* was also measured via single-component exponential fitting.
Numerical simulation suggests that the DIR technique provides perfect nulling of muscle and fat as well as efficient suppression of other long T tissues with T values between fat and water or those above water. Excellent image contrast can be achieved with DIR-UTE-Cones for the short T tissues, with fitted T2* values of 0.28-0.38 ms for cortical bone, 0.56 ± 0.07 ms for the patella tendon, and 0.45 ± 0.06 ms for the Achilles tendon, respectively.
The 3D DIR-UTE-Cones sequence provides robust suppression of long T tissues and allows selective imaging as well as T2* measurement of short T tissues such as cortical bone, patellar tendon, and the Achilles tendon. Magn Reson Med 79:2555-2563, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
利用三维双反转恢复超短回波时间锥形（3D DIR-UTE-Cones）序列研究短 T 组织的高对比度成像。
该序列使用两个连续的绝热反转脉冲来抑制长 T 组织的信号，然后进行多锥 UTE 采集以检测短 T 组织的信号。两个绝热反转脉冲完全相同，中心频率位于水峰，但光谱宽度足够宽以覆盖水和脂肪频率。通过数值模拟和体模研究证明了该技术的可行性。最后，将 DIR-UTE-Cones 应用于 3 名健康志愿者，以对皮质骨、髌腱和跟腱进行成像。还通过单指数拟合测量 T2*。
数值模拟表明，DIR 技术可完美地消除肌肉和脂肪，并有效地抑制 T 值在脂肪和水之间或高于水的其他长 T 组织。DIR-UTE-Cones 可实现短 T 组织的出色图像对比度，皮质骨的拟合 T2*值为 0.28-0.38 ms，髌腱为 0.56±0.07 ms，跟腱为 0.45±0.06 ms。
3D DIR-UTE-Cones 序列可提供长 T 组织的稳健抑制，并允许选择性成像以及皮质骨、髌腱和跟腱等短 T 组织的 T2*测量。磁共振医学 79:2555-2563, 2018。© 2017 国际磁共振学会。
