The effect of acquisition duration on cerebral blood flow‐based resting‐state functional connectivity

Resting‐state functional connectivity (rs‐FC) is widely used to examine the functional architecture of the brain, and the blood‐oxygenation‐level‐dependent (BOLD) signal is often utilized for determining rs‐FC. However, the BOLD signal is susceptible to various factors that have less influence on the cerebral blood flow (CBF). Therefore, CBF could comprise an alternative for determining rs‐FC. Since acquisition duration is one of the essential parameters for obtaining reliable rs‐FC, we investigated the effect of acquisition duration on CBF‐based rs‐FC to examine the reliability of CBF‐based rs‐FC. Nineteen participants underwent CBF scanning for a total duration of 50 min. Variance of CBF‐based rs‐FC within the whole brain and 13 large‐scale brain networks at various acquisition durations was compared to that with a 50‐min duration using the Levene's test. Variance of CBF‐based rs‐FC at any durations did not differ from that at a 50‐min duration (p > .05). Regarding variance of rs‐FC within each large‐scale brain network, the acquisition duration required to obtain reliable estimates of CBF‐based rs‐FC was shorter than 10 min and varied across large‐scale brain networks. Altogether, an acquisition duration of at least 10 min is required to obtain reliable CBF‐based rs‐FC. These results indicate that CBF‐based resting‐state functional magnetic resonance imaging (rs‐fMRI) with more than 10 min of total acquisition duration could be an alternative method to BOLD‐based rs‐fMRI to obtain reliable rs‐FC.