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bioRxiv · 10.1101/366955

Feasibility of Functional MRI at Ultralow Magnetic Field via Changes in Cerebral Blood Volume

Buckenmaier, K.·Pedersen, A.·SanGiorgio, P.·Scheffler, K.·Clarke, J.·Inglis, B.
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Abstract

We investigate the feasibility of performing functional MRI (fMRI) at ultralow field (ULF) with a Superconducting QUantum Interference Device (SQUID), as used for detecting magnetoencephalography (MEG) signals from the human head. While there is negligible magnetic susceptibility variation to produce blood oxygenation level-dependent (BOLD) contrast at ULF, changes in cerebral blood volume (CBV) may be a sensitive mechanism for fMRI given the five-fold spread in spin-lattice relaxation time (T1) values across the constituents of the human brain. We undertook simulations of functional signal strength for a simplified brain model involving activation of a primary cortical region in a manner consistent with a blocked task experiment. Our simulations involve measured values of T1 at ULF and experimental parameters for the performance of an upgraded ULFMRI scanner. Under ideal experimental conditions we predict a functional signal-to-noise ratio of between 3.1 and 7.1 for an imaging time of 30 minutes, or between 1.5 and 3.5 for a blocked task experiment lasting 7.5 minutes. Our simulations suggest it may be feasible to perform fMRI using a ULFMRI system designed to perform MRI and MEG in situ.

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Buckenmaier, K., Pedersen, A., SanGiorgio, P., Scheffler, K., Clarke, J., Inglis, B.. 2018-07-11. Feasibility of Functional MRI at Ultralow Magnetic Field via Changes in Cerebral Blood Volume. https://doi.org/10.1101/366955

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