Regional cerebral blood volume response to hypocapnia using susceptibility contrast MRI

MRI measurement of the BOLD-specific flow–volume relationship during hypercapnia and hypocapnia in humans

“…It has been commonly observed in hyperventilation as well as manual gas delivery paradigms (Ito et al, 2008;Kastrup et al, 1999;Payen et al, 2003). This issue has been reasonably resolved in animal studies through the use of mechanical ventilation, but remains largely unaddressed in human studies (Ito et al, 2003).…”

Bayesian estimation of changes in transverse relaxation rates

“…Such changes can be brought about by the administration of paramagnetic contrast agents such as gadolinium chelates (1), ultrasmall superparamagnetic iron oxide (USPIO) particles (2, 3), or inhalation of high oxygen content gases (4, 5). Such techniques can allow blood volume, flow, blood oxygenation, and/or vessel size to be estimated (4, 6–9).…”

Human Cerebral Blood Volume (CBV) Measured by Dynamic Susceptibility Contrast MRI and 99mTc-RBC SPECT

“…The use of hypocapnia to reduce CBV is well established and our measurements reproduce these findings. [11][12][13] Decreasing the ETCO 2 by 1.8 KPa reduced the global CBV from 4.3% ± 0.3% to 3.9% ± 0.5% of the brain volume (0.22% ± 0.16% per KPa pCO 2 ) in the 99m Tc-RBC SPECT group and from 4.2% ± 0.7% to 3.5% ± 0.8% of the brain volume (0.39% ± 0.32% per KPa pCO 2 ) in the DSC-MRI group: this means that the CBV reductions were similar in both the SPECT and DSC-MRI CBV, without significant differences.…”