Spatial heterogeneity of post‐contraction blood volume and oxygenation changes

Changes in blood flow, oxygenation, and volume following extended stimulation of rodent barrel cortex.

Simultaneous optical imaging spectroscopy and laser-Doppler flowmetry were used in rodent barrel cortex to examine the hemodynamic response to extended electrical stimulation (20 s, 5 Hz) of the whisker pad. Stimulation results in a fast early increase in deoxyhemoglobin concentration (Hbr) followed by a later decrease to a "plateau" phase approximately 4 s after stimulation onset. There was no...

The Effect of Acupuncture on Muscle Blood Volume and Oxygenation

Contributions of dynamic venous blood volume versus oxygenation level changes to BOLD fMRI

Blood-oxygenation-level-dependent (BOLD) fMRI has contributions from venous oxygenation and venous cerebral blood volume (CBV) changes. To examine the relative contribution of venous CBV change (ΔCBV(v)) to BOLD fMRI, BOLD and arterial CBV changes (ΔCBV(a)) to a 40-s forepaw stimulation in six α-chloralose anesthetized rats were measured using a magnetization transfer-varied fMRI technique, whi...

Vascular imprints of neuronal activity: relationships between the dynamics of cortical blood flow, oxygenation, and volume changes following sensory stimulation.

Modern functional neuroimaging methods, such as positron-emission tomography (PET), optical imaging of intrinsic signals, and functional MRI (fMRI) utilize activity-dependent hemodynamic changes to obtain indirect maps of the evoked electrical activity in the brain. Whereas PET and flow-sensitive MRI map cerebral blood flow (CBF) changes, optical imaging and blood oxygenation level-dependent MR...

Relative blood volume changes underestimate total blood volume changes during hemodialysis.

BACKGROUND Measurements of relative blood volume changes (DeltaRBV) during hemodialysis (HD) are based on hemoconcentration and assume uniform mixing of erythrocytes and plasma throughout the circulation. However, whole-body hematocrit (Ht) is lower than systemic Ht. During HD, a change in the ratio between whole-body to systemic Ht (F cell ratio) is likely to occur as a result of a net shift o...