Analysis of MR Signal Dynamics During Carbogen Inhalation Using a Combined Spin- And Gradient-Echo (SAGE) EPI Sequence

Georges Hankov¹, Thomas Christen¹, Heiko Schmiedeskamp¹, Roland Bammer¹, Greg Zaharchuk¹

The purpose of the study was to follow and analyze the dynamic changes in brain oxygenation induced by a carbogen respiratory challenge in normal human brain. Using a simple model and a multiple spin- and gradient-echo (SAGE) EPI sequence, maps of amplitude, wash-in and wash-out time constants, and arrival time delay of carbogen were computed. In 5 volunteers, we found a homogeneous response to carbogen and low inter-subject variability. This methodology could be used to study pathologies such as stroke or cancer.