Li D, Haacke E M, Tarr R W, Venkatesan R, Lin W, Wielopolski P
Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA.
J Magn Reson Imaging. 1996 May-Jun;6(3):415-24. doi: 10.1002/jmri.1880060302.
Short TR, short TE, high resolution, 3D gradient-recalled echo (GRE) imaging was evaluated for lesion detection in the brain. High resolution 3D GRE data acquisition was used to reduce partial volume effects and flow artifacts, to better visualize smaller structures, to minimize signal losses caused by field inhomogeneities, and to allow better image reformatting. Spin-echo (SE) and 3D GRE approaches were compared for lesion detection after the administration of an MR contrast agent, gadopentetate dimeglumine. Preliminary clinical studies demonstrated that the signal-to-noise ratio (SNR) in each slice of the GRE scan was worse than that of the SE scan because of the much thicker slices acquired with the SE technique. However, by averaging two adjacent 3D slices, the SNR of the two methods was essentially equivalent. In the averaged GRE slices, large lesions were seen just as well as in the SE images. More importantly, small lesions were better visualized in the thin 3D GRE images than in the thick SE images for the lesions studied in this work and the protocols used. These observations were confirmed by theoretical simulations.
对用于脑部病变检测的短TR、短TE、高分辨率三维梯度回波（GRE）成像进行了评估。采用高分辨率三维GRE数据采集来减少部分容积效应和流动伪影，更好地显示较小结构，将场不均匀性导致的信号损失降至最低，并实现更好的图像重格式化。在静脉注射磁共振造影剂钆喷酸葡胺后，比较了自旋回波（SE）和三维GRE方法在病变检测中的效果。初步临床研究表明，由于SE技术采集的切片更厚，GRE扫描各切片中的信噪比（SNR）低于SE扫描。然而，通过对相邻两个三维切片求平均，两种方法的SNR基本相当。在平均后的GRE切片中，大病变的显示效果与SE图像相当。更重要的是，对于本研究中所研究的病变以及所使用的方案，在薄的三维GRE图像中，小病变比在厚的SE图像中显示得更好。这些观察结果得到了理论模拟的证实。
