Calibrated BOLD using direct measurement of changes in venous oxygenation
| Autor: | Susan E. Pritchard, Emma L. Hall, Samuel Wharton, Susan T. Francis, Penny A. Gowland, Ian D. Driver |
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| Rok vydání: | 2012 |
| Předmět: |
CMRO2
Adult Male medicine.medical_specialty Cognitive Neuroscience Hyperoxia Motor Activity Stimulus (physiology) Brain mapping Article Young Adult Oxygen Consumption Internal medicine Image Interpretation Computer-Assisted medicine Humans Premovement neuronal activity BOLD calibration Brain Mapping medicine.diagnostic_test fMRI Brain Magnetic resonance imaging Venous blood Oxygenation Magnetic Resonance Imaging Oxygen Blood oxygenation Neurology Cerebral blood flow Cerebrovascular Circulation Anesthesia Cardiology Female sense organs medicine.symptom Psychology circulatory and respiratory physiology |
| Zdroj: | Neuroimage |
| ISSN: | 1053-8119 |
| DOI: | 10.1016/j.neuroimage.2012.08.045 |
| Popis: | Calibration of the BOLD signal is potentially of great value in providing a closer measure of the underlying changes in brain function related to neuronal activity than the BOLD signal alone, but current approaches rely on an assumed relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF). This is poorly characterised in humans and does not reflect the predominantly venous nature of BOLD contrast, whilst this relationship may vary across brain regions and depend on the structure of the local vascular bed. This work demonstrates a new approach to BOLD calibration which does not require an assumption about the relationship between cerebral blood volume and cerebral blood flow. This method involves repeating the same stimulus both at normoxia and hyperoxia, using hyperoxic BOLD contrast to estimate the relative changes in venous blood oxygenation and venous CBV. To do this the effect of hyperoxia on venous blood oxygenation has to be calculated, which requires an estimate of basal oxygen extraction fraction, and this can be estimated from the phase as an alternative to using a literature estimate. Additional measurement of the relative change in CBF, combined with the blood oxygenation change can be used to calculate the relative change in CMRO2 due to the stimulus. CMRO2 changes of 18 ± 8% in response to a motor task were measured without requiring the assumption of a CBV/CBF coupling relationship, and are in agreement with previous approaches. Highlights ► Venous blood oxygenation and CBV changes measured in response to a motor task. ► BOLD response to a motor task compared at normoxia and hyperoxia. ► BOLD calibration without assuming CBF/CBV coupling relationship. ► Motor task CMRO2 response of 18 ± 8% agrees with previous literature values. |
| Databáze: | OpenAIRE |
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