Department of Diagnostic and Interventional Radiology, Leipzig University Hospital, Leipzig, Germany.
J Magn Reson Imaging. 2013 Jun;37(6):1480-5. doi: 10.1002/jmri.23850. Epub 2012 Oct 10.
To present a novel method for MR elastography (MRE) of the prostate at 3 Tesla using a modified endorectal imaging coil.
A commercial endorectal coil was modified to dynamically generate mechanical stress (contraction and dilation) in a prostate phantom with embedded phantom "lesions" (6 mm diameter) and in a porcine model. Resulting tissue displacements were measured with a motion-sensitive EPI sequence at actuation frequencies of 50-200 Hz. Maps of shear modulus G were calculated from the measured phase-difference shear-wave patterns.
In the G maps of the phantom, "lesions" were easily discernible against the background. The average G values of regions of interest placed in the "lesion" (8.2 ± 1.9 kPa) were much higher than those in the background (3.6 ± 1.4 kPa) but systematically lower than values reported by the vendor (13.0 ± 1.0 and 6.7 ± 0.7 kPa, respectively). In the porcine model, shear waves could be generated and measured shear moduli were substantially different for muscle (7.1 ± 2.0 kPa), prostate (3.0 ± 1.4 kPa), and bulbourethral gland (5.6 ± 1.9 kPa).
An endorectal MRE concept is technically feasible. The presented technique will allow for simultaneous MRE and MRI acquisitions using a commercial base device with minor, MR-conditional modifications. The diagnostic value needs to be determined in further trials.
介绍一种在 3T 下使用改良的直肠内成像线圈进行前列腺磁共振弹性成像（MRE）的新方法。
对商用直肠内线圈进行改良，以在嵌入模拟“病变”（6mm 直径）的前列腺模拟体和猪模型中产生机械应力（收缩和扩张）。在激励频率为 50-200Hz 时，使用运动敏感的 EPI 序列测量组织位移。从测量的相差剪切波模式计算剪切模量 G 的地图。
在模拟体的 G 图中，“病变”与背景相比易于分辨。放置在“病变”中的感兴趣区域的平均 G 值（8.2±1.9kPa）明显高于背景（3.6±1.4kPa），但系统低于供应商报告的值（分别为 13.0±1.0kPa 和 6.7±0.7kPa）。在猪模型中，可以产生剪切波，并且肌肉（7.1±2.0kPa）、前列腺（3.0±1.4kPa）和球海绵体腺（5.6±1.9kPa）的测量剪切模量有很大差异。
直肠内 MRE 概念在技术上是可行的。所提出的技术将允许使用带有较小、符合 MR 条件的改良的商用基础设备进行同时 MRE 和 MRI 采集。诊断价值需要在进一步的试验中确定。
