# EUROISMAR 2019

25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

## Feasibility of functional MRI at ultralow magnetic field via changes in cerebral blood volume

Not scheduled
4h
Harnack House and Henry Ford Building

Board: 552
Poster-Late

### Speaker

Kai Buckenmaier (High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics)

### Description

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 (130 $\mu$T) and experimental parameters for the performance of an ULFMRI scanner with a noise level of 0.1 fT/Hz-1/2 and a prepolarizing field of 200 mT. 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 min, or between 1.5 and 3.5 for a blocked task experiment lasting 7.5 min. Our simulations suggest it may be feasible but challenging to perform fMRI using a ULFMRI system designed to perform MRI and MEG in situ.

### Primary authors

Kai Buckenmaier (High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics) Anders Pedersen (Department of Physics, University of California, Berkeley) Paul SanGiorgio (Department of Physics, University of California, Berkeley) Klaus Scheffler (High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics) John Clarke (Department of Physics, University of California, Berkeley) Ben Inglis (Henry H. Wheeler, Jr. Brain Imaging Center, University of California, Berkeley)

### Presentation Materials

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