Performance of a novel piezoelectric motor at 4.7 T: applications and initial tests

The focus of this report was to test the performance of a novel piezoelectric motor under high magnetic field strength conditions and to investigate its potential applications in small animal magnetic resonance imaging (MRI). The device is made entirely of nonferrous materials and consists of four piezoelectric ceramic plates connected to a threaded metal tube through which a screw migrates. Ultrasonic vibrations of the threads inherent to the tube result in rotational and translational motion of the screw. Potential applications of the piezoelectric motor were investigated at 4.7 T. Firstly, phantom studies showed the motor was capable of accurately delivering low injection volumes (∼0.01 ml). Dynamic contrast-enhanced MRI (DCE-MRI) studies performed in vivo using serially acquired T1-weighted, spin-echo imaging demonstrated the ability of the motor to reliably administer MR contrast-enhancing agent into live tumor-bearing mice without the introduction of image artifacts. In a second set of experiments, the motor allowed for controlled, dynamic repositioning of an anatomic slice of interest in a live animal to magnetic field isocenter, which resulted in reduced geometric distortion and image artifact due to improved radiofrequency and gradient field homogeneity. In conclusion, piezoelectric motors are MR compatible and offer great potential for improving MRI efficiency and throughput, particularly in a preclinical setting. Further investigation into applications such as automated capacitor tuning and impedance matching for MR transceiver coils is warranted.