Ma Jingfei
Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
J Magn Reson Imaging. 2008 Sep;28(3):543-58. doi: 10.1002/jmri.21492.
In 1984, Dixon published a first paper on a simple spectroscopic imaging technique for water and fat separation. The technique acquires two separate images with a modified spin echo pulse sequence. One is a conventional spin echo image with water and fat signals in-phase and the other is acquired with the readout gradient slightly shifted so that the water and fat signals are 180 degrees out-of-phase. Dixon showed that from these two images, a water-only image and a fat-only image can be generated. The water-only image by the Dixon's technique can serve the purpose of fat suppression, an important and widely used imaging option for clinical MRI. Additionally, the availability of both the water-only and fat-only images allows direct image-based water and fat quantitation. These applications, as well as the potential that the technique can be made highly insensitive to magnetic field inhomogeneity, have generated substantial research interests and efforts from many investigators. As a result, significant improvement to the original technique has been made in the last 2 decades. The following article reviews the underlying physical principles and describes some major technical aspects in the development of these Dixon techniques.
1984年，迪克森发表了第一篇关于一种用于水和脂肪分离的简单光谱成像技术的论文。该技术采用改进的自旋回波脉冲序列获取两幅单独的图像。一幅是传统的自旋回波图像，其中水和脂肪信号同相，另一幅是在读出梯度稍有偏移的情况下获取的，使得水和脂肪信号相差180度异相。迪克森表明，从这两幅图像中可以生成仅含水的图像和仅含脂肪的图像。迪克森技术生成的仅含水的图像可用于脂肪抑制，这是临床磁共振成像中一种重要且广泛应用的成像选项。此外，仅含水图像和仅含脂肪图像的可得性允许基于图像直接进行水和脂肪定量。这些应用，以及该技术对磁场不均匀性高度不敏感的潜力，引发了许多研究者的大量研究兴趣和努力。因此，在过去20年里，对原始技术有了显著改进。以下文章回顾了其基本物理原理，并描述了这些迪克森技术发展中的一些主要技术方面。
