Calibrated fMRI with a background-suppressed PCASL and multi-echo BOLD dual-acquisition sequence

Motivation: Calibrated fMRI quantitatively estimates cerebral metabolic rate of oxygen (CMRO2) by simultaneously measuring cerebral blood flow (CBF) with arterial spin labeling (ASL) and BOLD. Pseudo-continuous ASL (PCASL) with background suppression (BS) and 3D readout is recommended for CBF while multi-echo (ME) 2D BOLD has gained popularity. Nowadays, no calibrated fMRI sequence integrates both. Goal(s): Our goal is to combine them in a single sequence. Approach: We introduce a novel dual-acquisition calibrated fMRI sequence integrating BS-PCASL-3D GRASE for CBF and 2D multi-echo EPI BOLD. Results: Resting-state data in a healthy volunteer showed CBF values concordant with literature and improved BOLD tSNR and connectivity maps. Impact: We propose a novel sequence for calibrated fMRI that optimizes both CBF and BOLD measurements with a dual acquisition scheme, thus overcoming the limitations of previous ASL-BOLD calibrated fMRI sequences and showing promise for improved accuracy and reliability.