Dockery S E, Suddarth S A, Johnson G A
Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710.
Magn Reson Med. 1989 Aug;11(2):182-92. doi: 10.1002/mrm.1910110206.
Previous data on changes in tissue T1 with field have suggested the convergence of tissue T1 values toward a common value at high (greater than 4.0 T) fields. Measures of T2 dependence have suggested reduction of T2 with field. The purpose of this study was to observe the T1 and T2 at 85.5 and 300 MHz of microstructures in excised rat kidneys by employing MR microscopy. This study represents the first attempt of MR microscopy at 7.0 T with regard to the subject of magnetic field dependence of T1 and T2. As expected, T1 did increase with increasing field strength but not as dramatically as might be expected. Subtle differences in the microstructures of the kidney and the binding of water in those structures were discernible on the basis of T1 differences at 300 MHz. T2 values decreased, raising speculation concerning the mechanism for this dependence. The improved SNR permits smaller samples to be examined at much higher resolutions (greater than 30 X 30 X 200 microns), further extending the potentials for MR microscopy.
先前关于组织T1随磁场变化的数据表明，在高场（大于4.0 T）下组织T1值会趋向于一个共同的值。T2依赖性的测量表明T2随磁场而降低。本研究的目的是通过磁共振显微镜观察切除的大鼠肾脏中微观结构在85.5 MHz和300 MHz时的T1和T2。本研究是首次在7.0 T下就T1和T2的磁场依赖性这一主题进行磁共振显微镜研究。正如预期的那样，T1确实随着场强的增加而增加，但增加的幅度没有预期的那么大。基于300 MHz时的T1差异，可以辨别出肾脏微观结构以及这些结构中水分子结合情况的细微差异。T2值降低，这引发了对这种依赖性机制的推测。信噪比的提高使得能够以更高的分辨率（大于30×30×200微米）检测更小的样本，进一步扩展了磁共振显微镜的应用潜力。
