A chronic in situ coil system adapted for intracerebral stimulation during MRI in rats

Dan Madularu; Chathura Kumaragamage; Axel P Mathieu; Praveen Kulkarni; M Natasha Rajah; Alain P Gratton; Jamie Near

doi:10.1016/j.jneumeth.2017.04.018

A chronic in situ coil system adapted for intracerebral stimulation during MRI in rats

J Neurosci Methods. 2017 Jun 1:284:85-95. doi: 10.1016/j.jneumeth.2017.04.018. Epub 2017 Apr 29.

Authors

Dan Madularu¹, Chathura Kumaragamage², Axel P Mathieu³, Praveen Kulkarni⁴, M Natasha Rajah⁵, Alain P Gratton³, Jamie Near⁶

Affiliations

¹ Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, QC, Canada; Brain Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada. Electronic address: dan.madularu@gmail.com.
² Department of Biomedical Engineering, McGill University, Montreal, QC, Canada; Brain Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.
³ Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, QC, Canada; Brain Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.
⁴ Center for Translational Neuroimaging, Northeastern University, Boston, MA, USA.
⁵ Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, QC, Canada; Department of Psychology, Faculty of Arts, McGill University, Montreal, QC, Canada; Brain Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.
⁶ Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, QC, Canada; Department of Biomedical Engineering, McGill University, Montreal, QC, Canada; Brain Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.

PMID: 28460835
DOI: 10.1016/j.jneumeth.2017.04.018

Abstract

Background: We describe the fabrication and performance of a chronic in situ coil system designed to allow focal brain stimulation in rats while acquiring functional MRI data.

New method: An implantable receive-only surface radiofrequency coil (iCoil) was designed to be fitted subcutaneously, directly onto to the rat skull surface during the intracerebral cannulation procedure. The coil is fixed in place using acrylic dental cement anchored to four screws threaded into the skull. To demonstrate the use of this coil system in situ, whole-brain functional MRI scans were acquired during various stimuli, including intracranial microinfusions of bicuculline and morphine in the prefrontal cortex and ventral tegmental area, respectively.

Results/comparison to other methods: SNR performance of the iCoil was superior to three commercially-available coils, in some instances by a factor of two. Widespread BOLD activation was observed in response to bicuculline and morphine microinfusions.

Conclusion: A new approach was demonstrated for high-SNR MR imaging of the brain in rats with intracranial implants using an implantable surface coil. This approach enables mapping the functional response to highly targeted stimuli such as intracranial microinfusions.

Keywords: Animal imaging; BOLD; Cranial implant; Implantable RF coil; SNR.

MeSH terms

Animals
Brain / diagnostic imaging*
Deep Brain Stimulation / instrumentation*
Deep Brain Stimulation / veterinary*
Equipment Design
Equipment Failure Analysis
Infusion Pumps, Implantable*
Magnetic Resonance Imaging / instrumentation*
Magnetic Resonance Imaging / veterinary*
Male
Microinjections / instrumentation
Microinjections / veterinary*
Prostheses and Implants
Rats
Rats, Long-Evans
Reproducibility of Results
Sensitivity and Specificity
Transducers / veterinary