title: Slab-selective, BOLD-corrected VASO at 7 Tesla provides measures of cerebral blood volume reactivity with high signal-to-noise ratio.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors: Laurentius
authors: L
authors: Huber
authors: Dimo
authors: D
authors: Ivanov
authors: Steffen N
authors: SN
authors: Krieger
authors: Markus N
authors: MN
authors: Streicher
authors: Toralf
authors: T
authors: Mildner
authors: Benedikt A
authors: BA
authors: Poser
authors: Harald E
authors: HE
authors: Möller
authors: Robert
authors: R
authors: Turner
mesh_terms: D000328:Adult; D001810:Blood Volume; D002560:Cerebrovascular Circulation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D006935:Hypercapnia; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D013647:Task Performance and Analysis
keywords: 7 Tesla; cerebral blood volume; fMRI acquisition techniques; slab-selective VASO; vascular space occupancy