TY - JOUR
T1 - Slab-selective, BOLD-corrected VASO at 7 tesla provides measures of cerebral blood volume reactivity with high signal-to-noise ratio
AU - Huber, Laurentius
AU - Ivanov, Dimo
AU - Krieger, Steffen Norbert
AU - Streicher, Markus Nikolar
AU - Mildner, Toralf
AU - Poser, Benedikt Andreas
AU - Moller, Harald E
AU - Turner, Robert W
PY - 2014
Y1 - 2014
N2 - Purpose MRI methods sensitive to functional changes in cerebral blood volume (CBV) may map neural activity with better spatial specificity than standard functional MRI (fMRI) methods based on blood oxygen level dependent (BOLD) effect. The purpose of this study was to develop and investigate a vascular space occupancy (VASO) method with high sensitivity to CBV changes for use in human brain at 7 Tesla (T). Methods To apply 7T VASO, several high-field-specific obstacles must be overcome, e.g., low contrast-to-noise ratio (CNR) due to convergence of blood and tissue T1, increased functional BOLD signal change contamination, and radiofrequency field inhomogeneities. In the present method, CNR was increased by keeping stationary tissue magnetization in a steady-state different from flowing blood, using slice-selective saturation pulses. Interleaved acquisition of BOLD and VASO signals allowed correction for BOLD contamination. Results During visual stimulation, a relative CBV change of 28 ? 5 was measured, confined to gray matter in the occipital lobe with high sensitivity. Conclusion By carefully considering all the challenges of high-field VASO and filling behavior of the relevant vasculature, the proposed method can detect and quantify CBV changes with high CNR in human brain at 7T
AB - Purpose MRI methods sensitive to functional changes in cerebral blood volume (CBV) may map neural activity with better spatial specificity than standard functional MRI (fMRI) methods based on blood oxygen level dependent (BOLD) effect. The purpose of this study was to develop and investigate a vascular space occupancy (VASO) method with high sensitivity to CBV changes for use in human brain at 7 Tesla (T). Methods To apply 7T VASO, several high-field-specific obstacles must be overcome, e.g., low contrast-to-noise ratio (CNR) due to convergence of blood and tissue T1, increased functional BOLD signal change contamination, and radiofrequency field inhomogeneities. In the present method, CNR was increased by keeping stationary tissue magnetization in a steady-state different from flowing blood, using slice-selective saturation pulses. Interleaved acquisition of BOLD and VASO signals allowed correction for BOLD contamination. Results During visual stimulation, a relative CBV change of 28 ? 5 was measured, confined to gray matter in the occipital lobe with high sensitivity. Conclusion By carefully considering all the challenges of high-field VASO and filling behavior of the relevant vasculature, the proposed method can detect and quantify CBV changes with high CNR in human brain at 7T
UR - http://onlinelibrary.wiley.com/doi/10.1002/mrm.24916/pdf
U2 - 10.1002/mrm.24916
DO - 10.1002/mrm.24916
M3 - Article
VL - 72
SP - 137
EP - 148
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
SN - 0740-3194
IS - 1
ER -