A robust method for estimating CVR dynamics from breath-hold BOLD data without end-tidal carbon dioxide recordings

Cerebrovascular reactivity (CVR) can be estimated from the BOLD response to a vasoactive stimulus such as a breath-holding (BH) approximated by a sinusoidal regressor. We proposed a robust approach for estimating CVR using the frequency spectrum of BOLD data itself, without regressions or correlations with external recordings. We also estimated regional CVR time delay patterns using the BOLD signal phase relative to a non-brain reference. We demonstrate our pipeline in 18 healthy adults.