TrueBOLD: Detection of brain activity with TrueFISP

• Applicant: Professor Klaus Scheffler, Ph.D.
• Subject Area: Medical Physics, Biomedical Technology
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 320973753

TrueBOLD addresses the detection of neuronal activity in humans with magnetic resonance imaging based on the TrueFISP or balanced SSFP acquisition scheme at very high fields. Traditionally, blood oxygenation changes are detected with T2*-weighted echo planar sequences (EPI) that are sensitive to the static dephasing around small and larger vessels filled with deoxygenated blood. EPI is not specific to a certain type of vessel architecture or size, it sometimes shows blurring and blooming around larger vessels, it shows significant spatial distortions and thus severe challenges in precise co-registration to submillimeter anatomical scans. The proposed detection of BOLD changes with pass-band balanced SSFP, TrueBOLD, in combination with localized and dynamic shim arrays and strategies to minimize physiological signal fluctuations has the potential to overcome these limitations. The somewhat counterintuitive application of bSSFP at very high fields of 9.4T will boost the reduced sensitivity of this technique nearly into the range of EPI, but with significantly increased spatial specificity and absence of any spatial displacements. We will address a number of challenges and research questions that are linked to the fast and reliable implementation of bSSFP at 9.4T, as well as application of this technique in visual processing experiments to determine its spatial and neuronal point-spread-function. The ultimate goal is to advance TrueBOLD to the future standard for functional brain imaging at high fields.

• DFG Programme: Reinhart Koselleck Projects