Conturo T E, Kessler R M, Beth A H
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Magn Reson Med. 1990 Sep;15(3):397-419. doi: 10.1002/mrm.1910150307.
A pulse sequence is presented for obtaining a single image with combined T1/T2 weighting. T2 relaxation is made to increase intensity, in cooperation with the effect of T1 relaxation, by providing T2 weighting with a 90 degrees-180 degrees-90 degrees driven inversion pulse triplet in an inversion recovery method. Unlike the inversion spin-echo method having a short inversion time (TI), signals in the new driven inversion spin-echo (DISE) method need not be negative and the most T1-sensitive region of the recovery curve can be used. Selecting sensitivity to one relaxation time does not degrade the sensitivity to the other relaxation time. T1 sensitivity is thus extended to longer echo times (TE intervals). T2 sensitivity is extended to longer TI intervals, and the combined T1/T2-weighted technique with intermediate TE and TI has highly cooperative and near-maximal T1 and T2 effects on contrast. Intensity is not multiplicatively degraded by T1 and T2 weighting so that the signal-to-noise of the combined T1/T2-weighted method is high. High intensity and T1 and T2 cooperatively occur for a much wider range of relaxation times, and especially for images heavily weighted to the pathologic intermediate and long T1 and T2 regime.
本文提出了一种用于获取具有T1/T2加权组合的单一图像的脉冲序列。通过在反转恢复方法中使用90°-180°-90°驱动反转脉冲三联体提供T2加权，使T2弛豫与T1弛豫的效果协同作用以增加信号强度。与具有短反转时间（TI）的反转自旋回波方法不同，新的驱动反转自旋回波（DISE）方法中的信号无需为负，并且可以使用恢复曲线中对T1最敏感的区域。选择对一种弛豫时间的敏感度不会降低对另一种弛豫时间的敏感度。因此，T1敏感度扩展到更长的回波时间（TE间隔）。T2敏感度扩展到更长的TI间隔，并且具有中间TE和TI的T1/T2加权组合技术对对比度具有高度协同且接近最大的T1和T2效应。强度不会因T1和T2加权而呈乘法降低，因此T1/T2加权组合方法的信噪比很高。在更宽的弛豫时间范围内，尤其是对于严重加权于病理性中间和长T1及T2状态的图像，高强度以及T1和T2协同出现。
