Aneurin James Kennerley1,
Laurentius Huber2, Toralf Mildner2, John Edward Mayhew1,
Robert Turner3, Harald E. Mller2, Jason Berwick1
1Faculty
of Science, University of Sheffield, Sheffield, South Yorks., United Kingdom;
2Nuclear Magnetic Resonance Unit, Max Planck Institute for Human
Cognitive and Brain Sciences, Leipzig, Germany; 3Neurophysics, Max
Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
This in-vivo study quantifies a slice-selective-saturation (SSS) vascular space occupancy (VASO) fMRI sequence for measurement of Cerebral Blood Volume (CBV), at high field (7T). We compare SSS-VASO signal contrast with concurrent measurements of total hemoglobin (HbT) using 2-dimensional optical imaging spectroscopy (2D-OIS) in rat somatosensory cortex. VASO derived CBV changes are in good agreement in terms of both magnitude and temporal dynamics with HbT changes during both electrical stimulation and hypercapnic challenge. We observe 5-10% changes in CBV to stimulation in the rodent model - much lower than previously reported changes in human visual cortex (30-40%).