Paul Dominik, Markl Michael, Fautz Hans-Peter, Hennig Jürgen
Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany.
Magn Reson Med. 2006 Jul;56(1):82-93. doi: 10.1002/mrm.20922.
A new technique for acquiring T2-weighted, balanced steady-state free precession (b-SSFP) images is presented. Based on the recently proposed transition into driven equilibrium (TIDE) method, T2-TIDE uses a special flip angle scheme to achieve T2-weighted signal decay during the transient phase. In combination with half-Fourier image acquisition, T2-weighted images can be obtained using T2-TIDE. Numerical simulations were performed to analyze the signal behavior of T2-TIDE in comparison with TSE and b-SSFP. The results indicate identical signal evolution of T2-TIDE and TSE during the transient phase. T2-TIDE was used in phantom experiments, and quantitative ROI analysis shows a linear relationship between TSE and T2-TIDE SNR values. T2-TIDE was also applied to abdominal and head imaging on healthy volunteers. The resulting images were analyzed quantitatively and compared with standard T2-weighted and standard b-SSFP methods. T2-TIDE images clearly revealed T2 contrast and less blurring compared to T2-HASTE images. In combination with a magnetization preparation technique, STIR-weighted images were obtained. T2-TIDE is a robust technique for acquiring T2-weighted images while exploiting the advantages of b-SSFP imaging, such as high signal-to-noise ratio (SNR) and short TRs.
本文介绍了一种获取T2加权平衡稳态自由进动（b-SSFP）图像的新技术。基于最近提出的过渡到驱动平衡（TIDE）方法，T2-TIDE使用特殊的翻转角方案在瞬态阶段实现T2加权信号衰减。结合半傅里叶图像采集，使用T2-TIDE可以获得T2加权图像。进行了数值模拟，以分析T2-TIDE与快速自旋回波（TSE）和b-SSFP相比的信号行为。结果表明，在瞬态阶段，T2-TIDE和TSE的信号演变相同。T2-TIDE用于体模实验，定量感兴趣区（ROI）分析显示TSE和T2-TIDE信噪比（SNR）值之间存在线性关系。T2-TIDE还应用于健康志愿者的腹部和头部成像。对所得图像进行定量分析，并与标准T2加权和标准b-SSFP方法进行比较。与T2-HASTE图像相比，T2-TIDE图像清楚地显示了T2对比度且模糊较少。结合磁化准备技术，获得了短TI反转恢复（STIR）加权图像。T2-TIDE是一种强大的技术，可在利用b-SSFP成像优势（如高信噪比（SNR）和短重复时间（TR））的同时获取T2加权图像。
