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Noninvasive MRI measurement of the absolute cerebral blood volume–cerebral blood flow relationship during visual stimulation in healthy humans
Author(s) -
Ciris Pelin Aksit,
Qiu Maolin,
Constable R. Todd
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24984
Subject(s) - cerebral blood flow , cerebral blood volume , medicine , blood volume , blood flow , stimulation , hemodynamics , cardiology , neuroscience , psychology
Purpose The relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF) underlies blood oxygenation level–dependent functional MRI signal. This study investigates the potential for improved characterization of the CBV‐CBF relationship in humans, and examines sex effects as well as spatial variations in the CBV‐CBF relationship. Methods Healthy subjects were imaged noninvasively at rest and during visual stimulation, constituting the first MRI measurement of the absolute CBV‐CBF relationship in humans with complete coverage of the functional areas of interest. Results CBV and CBF estimates were consistent with the literature, and their relationship varied both spatially and with sex. In a region of interest with stimulus‐induced activation in CBV and CBF at a significance level of the P < 0.05, a power function fit resulted in CBV = 2.1 CBF 0.32 across all subjects, CBV = 0.8 CBF 0.51 in females and CBV = 4.4 CBF 0.15 in males. Exponents decreased in both sexes as ROIs were expanded to include less significantly activated regions. Conclusion Consideration for potential sex‐related differences, as well as regional variations under a range of physiological states, may reconcile some of the variation across literature and advance our understanding of the underlying cerebrovascular physiology. Magn Reson Med 72:864–875, 2014. © 2013 Wiley Periodicals, Inc.