Dual-Source Parallel Radiofrequency Excitation Body MR Imaging Compared with Standard MR Imaging at 3.0 T: Initial Clinical Experience
Dual-Source Parallel Radiofrequency Excitation Body MR Imaging Compared with Standard MR Imaging at 3.0 T: Initial Clinical Experience
复制标题
DOI：
10.1148/radiol.10092127
复制
发表时间：
2010-09-01
期刊：
影响因子：
19.7
通讯作者：
Schild, Hans H.
中科院分区：
文献类型：
--
作者：
Willinek, Winfried A.;Gieseke, Juergen;Schild, Hans H.
目的：前瞻性比较在3.0 T下使用具有并行传输和独立RF匀场的双源并行射频（RF）激励身体MR成像系统获得的磁共振（MR）图像的图像质量和均匀性与使用常规临床使用的标准序列获得的单源MR图像的图像质量和均匀性。材料和方法：在获得机构审查委员会批准和患者知情同意后，使用具有独立RF匀场和并行传输技术的双源并行RF激励3.0-T MR系统对28名患者进行检查，并与具有单RF传输的标准3.0-T MR系统进行比较。通过使用两个具有完全软件控制的射频发射源将射频功率分配到系统体线圈的独立端口，从而能够独立控制射频波形的相位和振幅。通过使用双源和单源RF激发获得轴向T2加权快速自旋回波（SE）和弥散加权（DW）肝脏图像、轴向T2加权快速SE骨盆图像以及矢状位T1和T2加权快速SE脊柱图像。两名放射科医生独立评价了图像的均匀性和图像质量。使用非参数Wilcoxon符号秩检验计算统计学显著性。结果：图像质量比较显示，在T2加权肝脏MR成像（P = 0.001，kappa = 1.00）和DW肝脏成像（P = 0.066，tau-b > 0.7）中，双源RF激励的结果明显优于单源RF激励。由于减少了局部能量沉积，双源RF激励骨盆和脊柱MR成像可以实现更少的采集和更短的重复时间，与单源RF激励的采集相比，图像采集加速了18%、33%和50%。两种MR技术之间的图像质量无显著差异（P > 0.05，tau-b > 0.5）。结论：双源并行RF激励体部MR成像能够减少介电阴影，改善RF磁感应场的均匀性，并在3.0 T下加速成像。(C)RSNA，2010年
Purpose: To prospectively compare the image quality and homogeneity of magnetic resonance (MR) images obtained by using a dual-source parallel radiofrequency (RF) excitation body MR imaging system with parallel transmission and independent RF shimming with the image quality and homogeneity of single-source MR images obtained by using standard sequences for routine clinical use in patients at 3.0 T.Materials and Methods: After institutional review board approval and informed patient consent were obtained, a dual-source parallel RF excitation 3.0-T MR system with independent RF shimming and parallel transmission technology was used to examine 28 patients and was compared with a standard 3.0-T MR system with single RF transmission. The RF power was distributed to the independent ports of the system body coil by using two RF transmission sources with full software control, enabling independent control of the phase and amplitude of the RF waveforms. Axial T2-weighted fast spin-echo (SE) and diffusion-weighted (DW) liver images, axial T2-weighted fast SE pelvic images, and sagittal T1- and T2-weighted fast SE spinal images were obtained by using dual- and single-source RF excitation. Two radiologists independently evaluated the images for homogeneity and image quality. Statistical significance was calculated by using the nonparametric Wilcoxon signed rank test. Interobserver agreement was determined by using Cohen kappa and Kendall tau-b tests.Results: Image quality comparisons revealed significantly better results with dual-source rather than single-source RF excitation at T2-weighted liver MR imaging (P = .001, kappa = 1.00) and better results at DW liver imaging at a statistical trend level (P = .066, tau-b > 0.7). Owing to reduced local energy deposition, fewer acquisitions and shorter repetition times could be implemented with dual-source RF excitation pelvic and spinal MR imaging, with image acquisition accelerating by 18%, 33%, and 50% compared with the acquisitions with single-source RF excitation. Image quality did not differ significantly between the two MR techniques (P > .05, tau-b > 0.5).Conclusion: Dual-source parallel RF excitation body MR imaging enables reduced dielectric shading, improved homogeneity of the RF magnetic induction field, and accelerated imaging at 3.0 T. (C) RSNA, 2010