Brainmap: Echo-planar imaging of cerebral physiology and metabolism at 7 Tesla
MGH Martinos Center
This seminar will summarize our recent efforts in quantifying physiology and metabolism of the brain by means of echo-planar imaging (EPI) at high magnetic field strength (7 Tesla). Quantification of brain function by fMRI techniques based on EPI is hampered by the presence of physiological sources of instability due to motion, heartbeat, and respiration. In our previous research, we investigated novel methods to deal with this limitation, by optimizing physiologic noise removal. In our current research, we exploited this limitation as an opportunity to investigate cerebral physiology, by considering physiological noise as a “signal of interest”. In this seminar we will talk about the effects in EPI time-courses of: paramagnetic oxygen moving inside the chest during respiration; cardiac and respiratory pressure waves traveling in the brain; changes in the cardiac rate and in the respiratory volume rate. We will show the different contribution of these effects to magnitude and phase EPI time-courses, and how they can be used to investigate cerebrovascular compliance and the hemodynamic waveform in the brain.