Design and implementation of embedded 8‐channel receive‐only arrays for whole‐brain MRI and fMRI of conscious awake marmosets

• Published in: Magnetic resonance in medicine Vol. 78; no. 1; pp. 387 - 398
• Main Authors: Papoti, Daniel, Yen, Cecil Chern‐Chyi, Hung, Chia‐Chun, Ciuchta, Jennifer, Leopold, David A., Silva, Afonso C.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-07-2017
• Subjects: Animals; Arrays; Brain; Brain mapping; Brain Mapping - instrumentation; Brain Mapping - veterinary; Callithrix; Computer-Aided Design; Decoupling; embedded RF coils; Equipment Design; Equipment Failure Analysis; Functional magnetic resonance imaging; Helmets; Image Enhancement - instrumentation; Impedance; Input impedance; Magnetic resonance imaging; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - veterinary; Male; MRI phased arrays; Nervous system; nonhuman primates; Photic Stimulation - methods; Preamplifiers; Protective equipment; Radio frequency; receive‐only RF coils; Reproducibility of Results; Sensitivity; Sensitivity and Specificity; Spatial discrimination; Spatial resolution; Stimulation; Transducers - veterinary; Visual cortex; Visual Cortex - anatomy & histology; Visual Cortex - physiology; Visual stimuli; Wakefulness; MRI phased arrays; receive-only RF coils; nonhuman primates; functional magnetic resonance imaging; embedded RF coils
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.26339

Purpose
The common marmoset (Callithrix jacchus) is a New World primate of increasing interest to neuroscience and in translational brain research. The present work describes the design and implementation of individualized 8‐channel receive‐only radiofrequency (RF) coil arrays that provide whole‐brain coverage and allow anatomical and functional MRI experiments in conscious, awake marmosets.
Methods
The coil arrays were designed with their elements embedded inside individualized restraint helmets. The size, geometry, and arrangement of the coil elements were optimized to allow whole‐brain coverage. Coil‐to‐coil decoupling was achieved by a combination of geometric decoupling and low input impedance preamplifiers. The performance of the embedded arrays was compared against that of one 8‐channel receive‐only array built to fit the external surface of the helmets.
Results
Three individualized helmets with embedded coil arrays were built for three marmosets. Whole‐brain coverage was achieved with high sensitivity extending over the entire cortex. Visual stimulation of conscious awake marmosets elicited robust BOLD fMRI responses in both primary and higher order visual areas of the occipitotemporal cortex.
Conclusion
The high sensitivity provided by embedded receive‐only coil arrays allows both anatomical and functional MRI data to be obtained with high spatial resolution in conscious, awake marmosets. Magn Reson Med 78:387–398, 2017. © 2016 International Society for Magnetic Resonance in Medicine