Validation of a New Coil Array Tailored for Dog Functional Magnetic Resonance Imaging Studies

Abstract

Comparative neuroimaging allows for the identification of similarities and differences between species. It provides an important and promising avenue, to answer questions about the evolutionary origins of the brain´s organization, in terms of both structure and function. Dog fMRI has recently become one particularly promising and increasingly used approach to study brain function and coevolution. In dog neuroimaging, image acquisition has so far been mostly performed with coils originally developed for use in human MRI. Since such coils have been tailored to human anatomy, their sensitivity and data quality is likely not optimal for dog MRI. Therefore, we developed a multi-channel receive coil (K9 coil, read “canine”) tailored for high-resolution functional imaging in canines, optimized for dog cranial anatomy. In this paper we report structural (n = 9) as well as functional imaging data (resting-state, n = 6; simple visual paradigm, n = 9) collected with the K9 coil in comparison to reference data collected with a human knee coil. Our results show that the K9 coil significantly outperforms the human knee coil, improving the signal-to-noise ratio across the imaging modalities. We noted increases of roughly 45% signal-to-noise in the structural and functional domain. In terms of translation to functional fMRI data collected in a visual flickering checkerboard paradigm, group-level analyses show that the K9 coil performs better than the knee coil as well. These findings demonstrate how hardware improvements may be instrumental in driving data quality, and thus, quality of imaging results, for dog-human comparative neuroimaging.Significance StatementComparative neuroimaging is a powerful avenue to discover evolutionary mechanisms at the brain level. However, data quality is a major constraint in non-human functional magnetic resonance imaging. We describe a novel canine head coil for magnetic resonance imaging, designed specifically for dog cranial anatomy. Data quality performance and improvements over previously used human knee coils are described quantitatively. In brief, the canine coil improved signal quality substantially across both structural and functional imaging domains, with strongest improvements noted on the cortical surface.

Central nodes of canine functional brain networks are concentrated in the cingulate gyrus

“…In contrast, the whole dog LPFC belongs to a single resting state network (Dorsal/lateral prefrontal). The lack of separate attention and control networks in dogs could be a byproduct of the limits of the currently available image resolution, which can be further improved by developing coils specifically tailored to measure dogs (Guran et al 2022). Alternatively, in dogs, the cingulate cortex may be handling some integrative functions which were taken over by frontoparietal regions during primate brain evolution.…”

Action observation reveals a network with divergent temporal and parietal lobe engagement in dogs compared to humans

“…( A ) Dogs were positioned in sphinx position with their head placed in a custom-made 16-channel (k9) head coil 53 . For human participants, data were obtained with the same Siemens 3T scanner but with a 32-channel human head coil in a supine position and with stimuli presented via a back-projection mirror mounted on the coil (not shown).…”

“…MRI data for the action observation task was obtained using a custom-made 16- channel (k9) head coil for the dog participants 53 and a 32-channel head coil for human participants, used in a 3T Siemens Skyra MR-system (Siemens Medical, Erlangen, Germany). For three dogs, we used structural scans which had been previously acquired with a 15-channel human knee coil due to unavailability of the dogs to acquire a new structural scan.…”

Functional mapping of the somatosensory cortex using noninvasive fMRI and touch in awake dogs

“…Dogs in our sample had undergone extensive prior training to enable awake and unrestrained MRI scanning (Karl et al 2020 ) and successfully participated in several prior studies (Boch et al 2021 , 2023 ; Guran et al 2023 ; Karl et al 2020b , 2021 ). For the present study, they additionally underwent familiarization with the touching rod and touching procedure.…”