Quantitative Magnetic Resonance Imaging in Experimental Hypercapnia: Improvement in the Relation between Changes in Brain R2* and the Oxygen Saturation of Venous Blood after Correction for Changes in Cerebral Blood Volume
| Autor: | Azim Celik, Richard P. Paczynski, William J. Powers, Weili Lin, Chung Y. Hsu |
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| Rok vydání: | 1999 |
| Předmět: |
Male
Partial Pressure Quantitative magnetic resonance imaging chemistry.chemical_element Blood volume Oxygen 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Nuclear magnetic resonance Image Processing Computer-Assisted medicine Animals Rats Long-Evans Oxygen saturation (medicine) Blood Volume medicine.diagnostic_test business.industry Brain Magnetic resonance imaging Venous blood Carbon Dioxide Hydrogen-Ion Concentration Magnetic Resonance Imaging Rats Cerebral blood volume Neurology chemistry Regional Blood Flow Cerebrovascular Circulation Anesthesia Regression Analysis Neurology (clinical) medicine.symptom Cardiology and Cardiovascular Medicine business Hypercapnia 030217 neurology & neurosurgery |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1559-7016 0271-678X |
| Popis: | Acute hypercapnia simultaneously induces increases in regional cerebral blood volume (rCBV) and the oxygen saturation of cerebral venous blood (Yv). Changes in both physiologic parameters may influence the changes in R2* (ΔR2*) that can be measured in the brain with gradient echo magnetic resonance imaging. The authors examined the effect of incorporating independent measurements of the change in rCBV (ΔrCBV) on the fidelity of the relation between ΔR2* and ΔYv in the setting of experimental hypercapnia. A two-dimensional T2*-weighted gradient echo sequence was used to measure ΔR2* in the brain parenchyma of anesthetized rats in response to hypercapnia with respect to the control state. In parallel, estimates of rCBV were obtained using a three-dimensional steady-state approach in conjunction with a paramagnetic contrast agent during both control and hypercapnic states so that a ΔrCBV could be calculated. Regional CBV values of 2.96 ± 0.82% and 5.74 ± 1.21% were obtained during the control and hypercapnic states, respectively, and linear relations between rCBV and CO2 tension in both arterial ( r = 0.80) and jugular venous ( r = 0.76) blood samples were obtained. When correlating ΔR2* directly with ΔYv, no clear relation was apparent, but a strong linear relation ( r = 0.76) was observed when correction for ΔrCBV was incorporated into the data analysis. These results are consistent with the current understanding of the mechanisms of blood oxygen level–dependent (BOLD) contrast and underscore the potential importance of taking into account ΔrCBV when quantitative estimates of ΔYv from the “BOLD effect” are intended. |
| Databáze: | OpenAIRE |
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