Investigation of venous effects in spinal cord fMRI using hypercapnia

Introduction An effective non-invasive method of assessing spinal function would be of great clinical importance. However, a better understanding of neurovascular coupling in the spinal cord is needed for a reliable use of the BOLD technique in a clinical context. In recent studies, hypercapnia was used as a control stimulus to study the sensitivity of BOLD responses in the spinal cord [1,2]. Hypercapnia is known to cause large increases in perfusion and subsequently in BOLD signal [3]. In this study we built further on this investigation by (i) comparing responses to hypercapnia in the spinal cord and the brain, (ii) adding a motor task to the protocol and (iii) acquiring susceptibility weighted images (SWI) to investigate the spatial concordance of the most significant responses with large veins.