Coherent Hemodynamics Spectroscopy for Dynamic Measurements of Absolute Cerebral Blood Flow

Abstract

Coherent Hemodynamics Spectroscopy (CHS) is a novel technique for quantitative assessment of cerebral hemodynamics based on dynamic near infrared spectroscopy (NIRS) measurements. Here, we present a new approach for dynamic measurements of absolute cerebral blood flow (CBF) with NIRS and CHS in one healthy subject during transient changes of mean arterial pressure (MAP) in normal breathing and in hyperventilation conditions. Hyperventilation is known to reduce blood flow and enhance cerebral autoregulation. During hyperventilation, with respect to normal breathing at baseline, we found a lower absolute CBF (hyperventilation: 32 ± 3 ml/100 g/min; normal breathing: 35 ± 3 ml/100 g/min) and a faster CBF recovery to baseline (time of half recovery: 6 s for hyperventilation; 11 s for normal breathing). These results demonstrate the application of NIRS and CHS for quantitative, noninvasive, dynamic measurements of cerebral perfusion and cerebral autoregulation in the local cerebral microcirculation.