Streamlining the Design and Use of Array Coils for In Vivo Magnetic Resonance Imaging of Small Animals

Abstract

Small-animal models such as rodents and non-human primates play an important pre-clinical role in the study of human disease, with particular application to cancer, cardiovascular, and neuroscience models. To study these animal models, magnetic resonance imaging (MRI) is advantageous as a non-invasive technique due to its versatile contrast mechanisms, large and flexible field of view, and straightforward comparison/translation to human applications. However, signal-to-noise ratio (SNR) limits the practicality of achieving the high-resolution necessary to image the smaller features of animals in an amount of time suitable for in vivo animal MRI. In human MRI, it is standard to achieve an increase in SNR through the use of array coils; however, the design, construction, and use of array coils for animal imaging remains challenging due to copper-loss related issues from small array elements and design complexities of incorporating multiple elements and associated array hardware in a limited space. In this work, a streamlined strategy for animal coil array design, construction, and use is presented and the use for multiple animal models is demonstrated. New matching network circuits, materials, assembly techniques, body-restraining systems and integrated mechanical designs are demonstrated for streamlining high-resolution MRI of both anesthetized and awake animals. The increased SNR achieved with the arrays is shown to enable high-resolution in vivo imaging of mice and common marmosets with a reduced time for experimental setup.