Harvard Medical School, Radiology Department, Brigham and Women's Hospital, 221 Longwood Avenue, LM-010, Boston, MA 02115, USA.
Int J Med Robot. 2011 Sep;7(3):353-60. doi: 10.1002/rcs.405. Epub 2011 Jul 25.
MR elastography (MRE) is an emerging technique for tumor diagnosis. MRE actuation devices require precise mechanical design and radiofrequency engineering to achieve the required mechanical vibration performance and MR compatibility.
A method of designing a general-purpose, compact and inexpensive MRE actuator is presented. It comprises piezoelectric bimorphs arranged in a resonant structure designed to operate at its resonant frequency for maximum vibration amplitude. An analytical model was established to understand the device vibration characteristics.
The model-predicted performance was validated in experiments, showing its accuracy in predicting the actuator resonant frequency with an error < 4%. The device MRI compatibility was shown to cause minimal interference to a 1.5 tesla MRI scanner, with maximum signal-to-noise ratio reduction of 7.8% and generated artefact of 7.9 mm in MR images.
A piezoelectric MRE actuator is proposed, and its implementation, vibration issues and future work are discussed.
磁共振弹性成像（MRE）是一种新兴的肿瘤诊断技术。MRE 驱动装置需要精确的机械设计和射频工程，以实现所需的机械振动性能和磁共振兼容性。
提出了一种通用、紧凑、廉价的 MRE 驱动器的设计方法。它由布置在谐振结构中的压电双晶片组成，设计为在谐振频率下工作以获得最大振动幅度。建立了一个分析模型来了解设备的振动特性。
模型预测的性能在实验中得到了验证，表明其在预测致动器的谐振频率时具有小于 4%的误差。该设备的磁共振兼容性显示对 1.5 特斯拉磁共振扫描仪的干扰最小，最大信噪比降低 7.8%，MR 图像中产生的伪影为 7.9 毫米。
提出了一种压电 MRE 驱动器，并讨论了其实现、振动问题和未来工作。
