Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK.
Clin Radiol. 2012 Mar;67(3):258-62. doi: 10.1016/j.crad.2011.08.022. Epub 2011 Oct 19.
To demonstrate the feasibility of obtaining liver stiffness measurements with magnetic resonance elastography (MRE) at 3T in normal healthy volunteers using the same technique that has been successfully applied at 1.5 T.
The study was approved by the local ethics committee and written informed consent was obtained from all volunteers. Eleven volunteers (mean age 35 ± 9 years) with no history of gastrointestinal, hepatobiliary, or cardiovascular disease were recruited. The magnetic resonance imaging (MRI) protocol included a gradient echo-based MRE sequence using a 60 Hz pneumatic excitation. The MRE images were processed using a local frequency estimation inversion algorithm to provide quantitative stiffness maps. Adequate image quality was assessed subjectively by demonstrating the presence of visible propagating waves within the liver parenchyma underlying the driver location. Liver stiffness values were obtained using manually placed regions of interest (ROI) outlining the liver margins on the gradient echo wave images, which were then mapped onto the corresponding stiffness image. The mean stiffness values from two adjacent sections were recorded.
Eleven volunteers underwent MRE. The quality of the MRE images was adequate in all the volunteers. The mean liver stiffness for the group was 2.3 ± 0.38 kPa (ranging from 1.7-2.8 kPa).
This preliminary work using MRE at 3T in healthy volunteers demonstrates the feasibility of liver stiffness evaluation at 3T without modification of the approach used at 1.5 T. Adequate image quality and normal MRE values were obtained in all volunteers. The obtained stiffness values were in the range of those reported for healthy volunteers in previous studies at 1.5 T. There was good interobserver reproducibility in the stiffness measurements.
证明在正常健康志愿者中使用已在 1.5T 成功应用的相同技术在 3T 下获得磁共振弹性成像（MRE）肝硬度测量的可行性。
该研究得到了当地伦理委员会的批准，并获得了所有志愿者的书面知情同意。招募了 11 名无胃肠道、肝胆或心血管疾病史的志愿者（平均年龄 35 ± 9 岁）。磁共振成像（MRI）方案包括使用基于梯度回波的 MRE 序列，采用 60Hz 气动激励。MRE 图像使用局部频率估计反演算法进行处理，以提供定量的硬度图。通过证明在驱动器位置下方的肝实质内存在可见的传播波来主观评估足够的图像质量。使用手动放置的 ROI 获得肝硬度值，该 ROI 勾勒出梯度回波波图像上的肝边缘，然后将其映射到相应的硬度图像上。记录两个相邻节段的平均硬度值。
11 名志愿者接受了 MRE。所有志愿者的 MRE 图像质量均足够。该组的平均肝硬度为 2.3 ± 0.38kPa（范围为 1.7-2.8kPa）。
这项在健康志愿者中使用 3T 的 MRE 的初步工作表明，无需修改在 1.5T 下使用的方法即可在 3T 下进行肝硬度评估。所有志愿者均获得了足够的图像质量和正常的 MRE 值。获得的硬度值在之前在 1.5T 下进行的健康志愿者研究报告的范围内。在硬度测量中具有良好的观察者间可重复性。
