Ohkubo Masaki, Ohgoshi Yukio, Naito Kenichi, Yagishita Yuhko, Tsai Du-Yih
Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2003 Jul;59(7):879-82. doi: 10.6009/jjrt.kj00003174218.
The aim of the present study was to evaluate the increase in signal intensity caused by applying the fast recovery (FR) technique to fast spin echo (FSE) images, that is, the fast recovery fast spin echo (FR-FSE) method. All images of phantoms, whose T(2) values were different, were acquired with a Signa 1.5 Tesla system (GE Medical Systems) using the three-dimensional (3D) FSE and 3D FR-FSE sequences. We assessed the increased signal intensity as follows: (signal intensity on the FR-FSE image - FSE image) / FSE image (%). Our results showed that the increased signal intensity became high when 1) T(2) of the phantom was prolonged, 2) TR was shortened, and 3) echo train length (ETL) was decreased. By utilizing the results of this study, the increased signal caused by the FR technique could be estimated quantitatively when the TR, ETL, and T(2) of investigated substances were determined. For example, when TR, ETL, and T(2) were 1500 msec, 16-64, and 1500 msec, respectively, the increase in signal intensity was estimated to be approximately 70%. In addition, when T(2) was less than approximately 250 msec, signal intensity was not significantly increased by the FR pulses, that is, the FR-FSE image was the same as the FSE image. Accordingly, the FR-FSE method was confirmed to enhance the signal in substances with longer T(2), while maintaining the same contrast of the image as that obtained by the conventional FSE method. Our results are useful for evaluating the increased signal intensity caused by employing the FR technique.
本研究的目的是评估将快速恢复（FR）技术应用于快速自旋回波（FSE）图像，即快速恢复快速自旋回波（FR-FSE）方法所导致的信号强度增加。使用Signa 1.5特斯拉系统（GE医疗系统公司），通过三维（3D）FSE和3D FR-FSE序列采集了T(2)值不同的所有体模图像。我们按如下方式评估信号强度的增加：（FR-FSE图像上的信号强度 - FSE图像上的信号强度）/FSE图像（%）。我们的结果表明，当满足以下条件时，信号强度的增加会变高：1）体模的T(2)延长；2）重复时间（TR）缩短；3）回波链长度（ETL）减小。利用本研究的结果，当确定了被研究物质的TR、ETL和T(2)时，就可以定量估计由FR技术引起的信号增加。例如，当TR、ETL和T(2)分别为1500毫秒、16 - 64和1500毫秒时，信号强度的增加估计约为70%。此外，当T(2)小于约250毫秒时，FR脉冲不会使信号强度显著增加，即FR-FSE图像与FSE图像相同。因此，证实了FR-FSE方法在增强T(2)较长的物质中的信号的同时，保持了与传统FSE方法获得的图像相同的对比度。我们的结果对于评估采用FR技术所导致的信号强度增加很有用。
