Blood oxygenation level dependent, blood volume, and blood flow responses to carbogen and hypoxic hypoxia in 9L rat gliomas as measured by MRI

2013 ◽  
Vol 39 (1) ◽  
pp. 110-119 ◽  
Author(s):  
Neil P. Jerome ◽  
S. Khan Hekmatyar ◽  
Risto A. Kauppinen
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Hypoxic Hypoxia ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

scholarly journals Anatomical, blood oxygenation level-dependent, and blood flow MRI of nonhuman primate (baboon) retina

2011 ◽  
Vol 66 (2) ◽  
pp. 546-554 ◽  
Author(s):  
Yi Zhang ◽  
Hsiao-Ying Wey ◽  
Oscar San Emeterio Nateras ◽  
Qi Peng ◽  
Bryan H. De La Garza ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nonhuman Primate ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Flow Mri

scholarly journals Quantitative aspects of brain perfusion dynamic induced by BOLD fMRI

2006 ◽  
Vol 64 (4) ◽  
pp. 895-898 ◽  
Author(s):  
Katia C. Andrade ◽  
Octavio M. Pontes-Neto ◽  
Joao P. Leite ◽  
Antonio Carlos Santos ◽  
Oswaldo Baffa ◽  
...  
Keyword(s):  
Blood Flow ◽  
Grey Matter ◽  
Brain Perfusion ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Breath Holding ◽  
Bold Signal ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Dependent Signal

The increase of relative cerebral blood flow (rCBF) may contribute for a change in blood oxygenation level dependent signal (BOLD). The main purpose of this study is to investigate some aspects of perfusional alterations in the human brain in response to a uniform stimulation: hypercapnia induced by breath holding. It was observed that the BOLD signal increased globally during hypercapnia and that it is correlated with the time of breath holding. This signal increase shows a clear distinction between gray and white matter, being greater in the grey matter.

The Effect of Esmolol on Cerebral Blood Flow, Cerebral Vasoreactivity, and Cognitive Performance: A Functional Magnetic Resonance Imaging Study

2005 ◽  
Vol 102 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Wolfgang Heinke ◽  
Stefan Zysset ◽  
Margret Hund-Georgiadis ◽  
Derk Olthoff ◽  
D Yves von Cramon
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Functional Magnetic Resonance Imaging ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

Background Esmolol is often applied perioperatively to maintain stable hemodynamic conditions in neurosurgical patients. Little is known, however, about its effects on cerebral circulation. The authors employed functional magnetic resonance imaging based on blood oxygenation level-dependent contrast to explore the effect of esmolol on the human brain. The purpose of the study was to investigate the effect of esmolol on cerebral blood flow, cerebral vasoreactivity, and cognitive performance. Methods Ten healthy volunteers were investigated in two separate experimental sessions using functional magnetic resonance imaging. During the first experimental session, a hyperventilation task and a cognitive task, subjects had to perform both tasks twice, once after administration of an esmolol bolus of 1 mg/kg followed by a continuous infusion of 150 microg.kg.min and once without beta-blockade, in a random order. During the second experimental session subjects were scanned at resting state after administration of esmolol. Furthermore, the effect of the esmolol dose on hemodynamic changes caused by beta-adrenergic stimulation with orciprenaline was investigated. Results Esmolol decreased heart rate and blood pressure during the various experimental conditions and blunted the increase in heart rate and blood pressure caused by orciprenaline. Infusion of esmolol affects neither the blood oxygenation level-dependent contrast during the functional challenges nor the reaction times during the cognitive task. However, the esmolol bolus caused a brief blood oxygenation level-dependent contrast increase. Conclusion The results indicate that effective beta-blockade with esmolol does not affect cerebral blood flow, cerebrovascular reactivity, or cognitive performance.

scholarly journals Quantitative analysis of the postcontractile blood-oxygenation-level-dependent (BOLD) effect in skeletal muscle

2011 ◽  
Vol 111 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Theodore F. Towse ◽  
Jill M. Slade ◽  
Jeffrey A. Ambrose ◽  
Mark C. DeLano ◽  
Ronald A. Meyer
Keyword(s):  
Blood Volume ◽  
Near Infrared ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Activity Level ◽  
Anterior Tibial Artery ◽  
Physically Active ◽  
Hemoglobin Saturation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

Previous studies show that transient increases in both blood flow and magnetic resonance image signal intensity (SI) occur in human muscle after brief, single contractions, and that the SI increases are threefold larger in physically active compared with sedentary subjects. This study examined the relationship between these transient changes by measuring anterior tibial artery flow (Doppler ultrasound), anterior muscle SI (3T, one-shot echo-planar images, TR/TE = 1,000/35), and muscle blood volume and hemoglobin saturation [near-infrared spectroscopy (NIRS)] in the same subjects after 1-s-duration maximum isometric ankle dorsiflexion contractions. Arterial flow increased to a peak 5.9 ± 0.7-fold above rest (SE, n = 11, range 2.6–10.2) within 7 s and muscle SI increased to a peak 2.7 ± 0.6% (range 0.0–6.0%) above rest within 12 s after the contractions. The peak postcontractile SI change was significantly correlated with both peak postcontractile flow ( r = 0.61, n = 11) and with subject activity level ( r = 0.63, n = 10) estimated from 7-day accelerometer recordings. In a subset of 7 subjects in which NIRS data acquisition was successful, the peak magnitude of the postcontractile SI change agreed well with SI calculated from the NIRS blood volume and saturation changes ( r = 0.80, slope = 1.02, intercept = 0.16), confirming the blood-oxygenation-level-dependent (BOLD) mechanism underlying the SI change. The magnitudes of postcontractile changes in blood saturation and SI were reproduced by a simple one-compartment muscle vascular model that incorporated the observed pattern of postcontractile flow, and which assumed muscle O2 consumption peaks within 2 s after a brief contraction. The results show that muscle postcontractile BOLD SI changes depend critically on the balance between O2 delivery and O2 consumption, both of which can be altered by chronic physical activity.

scholarly journals Carbogen-induced increases in tumor oxygenation depend on the vascular status of the tumor: A multiparametric MRI study in two rat glioblastoma models

2016 ◽  
Vol 37 (6) ◽  
pp. 2270-2282 ◽  
Author(s):  
Ararat Chakhoyan ◽  
Aurélien Corroyer-Dulmont ◽  
Marine M Leblond ◽  
Aurélie Gérault ◽  
Jérôme Toutain ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Volume Blood

The alleviation of hypoxia in glioblastoma with carbogen to improve treatment has met with limited success. Our hypothesis is that the eventual benefits of carbogen depend on the capacity for vasodilation. We examined, with MRI, changes in fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in response to carbogen. The analyses were performed in two xenograft models of glioma (U87 and U251) recognized to have different vascular patterns. Carbogen increased fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in contralateral tissues. In the tumor core and peritumoral regions, changes were dependent on the capacity to vasodilate rather than on resting fractional cerebral blood volume. In the highly vascularised U87 tumor, carbogen induced a greater increase in fractional cerebral blood volume and blood oxygen saturation in comparison to the less vascularized U251 tumor. The blood oxygenation level dependent signal revealed a delayed response in U251 tumors relative to the contralateral tissue. Additionally, we highlight the considerable heterogeneity of fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent within U251 tumor in which multiple compartments co-exist (tumor core, rim and peritumoral regions). Finally, our study underlines the complexity of the flow/metabolism interactions in different models of glioblastoma. These irregularities should be taken into account in order to palliate intratumoral hypoxia in clinical trials.

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