Michael Hütel1,2, Andrew Melbourne1, David L Thomas1,2, Jonathan Rohrer2, and Sebastien Ourselin1,2
1Translational Imaging Group, University College London, London, United Kingdom, 2Dementia Research Centre, University College London, London, United Kingdom
Previous studies have shown that slow variations in the cardiac cycle are coupled with signal changes in the blood-oxygen level dependent (BOLD) contrast. The detection of neurophysiological hemodynamic changes, driven by neuronal activity, is hampered by such physiological noise. It is therefore of great importance to model and remove these physiological artefacts. The cardiac cycle causes pulsatile arterial blood flow. This pulsation is translated into brain tissue and fluids bounded by the cranial cavity. We exploit this pulsality effect and provide evidence that the heart rate is inherent in BOLD fMRI images.
