Kölbel G, Klose U, Hess C F, Küper K, Grodd W
Radiologische Klinik, Universität Tübingen.
Rofo. 1988 Jun;148(6):674-82. doi: 10.1055/s-2008-1048271.
In this paper the signal intensity and parameter-weighting zones of spin echo and gradient echo sequences (FLASH) have been analysed. Using information available in the literature, with additional analytical and numerical techniques, it is possible to determine parameters which maximise tissue contrast for T1, T2 and proton-weighted images. The technique is equally applicable to spin echo and FLASH sequences. The advantages of optimised gradient echo sequences compared with spin echo sequences with respect to its signal to noise ratio for short repetition times are analysed quantitatively. T2-weighted images can be generated as rapid as T1-weighted images, using the FLASH sequences when using a small angle of spin and relatively long echo. Illustrations are shown to demonstrate the numerical results (field strength 1.5 tesla). This is followed by a discussion of possible opposing effects.
本文分析了自旋回波和梯度回波序列（快速低角度激发序列）的信号强度及参数加权区。利用文献中的现有信息，并结合额外的分析和数值技术，可以确定能使T1、T2和质子加权图像的组织对比度最大化的参数。该技术同样适用于自旋回波和快速低角度激发序列。定量分析了优化后的梯度回波序列与自旋回波序列相比，在短重复时间下其信噪比的优势。当采用小角度自旋和相对长的回波时，使用快速低角度激发序列可以像生成T1加权图像一样快速地生成T2加权图像。文中给出了示例以展示数值结果（场强1.5特斯拉）。随后讨论了可能存在的相反效应。
