scholarly journals Cerebral Blood Flow, Blood Volume, and Mean Transit Time Responses to Propofol and Indomethacin in Peritumor and Contralateral Brain Regions

2010 ◽  
Vol 112 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Mads Rasmussen ◽  
Niels Juul ◽  
Søren M. Christensen ◽  
Kristjana Y. Jónsdóttir ◽  
Carsten Gyldensted ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Tumors ◽  
Blood Volume ◽  
Transit Time ◽  
Gray Matter ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Brain Regions ◽  
Normal Brain

Background The regional cerebral blood flow (CBF) response to propofol and indomethacin may be abnormal in patients with brain tumors. First, the authors tested the hypothesis that during propofol anesthesia alone and combined with indomethacin, changes in CBF, cerebral blood volume (CBV), and plasma mean transit time (MTT) differ in the peritumoral tissue compared with the contralateral normal brain region. Second, the authors tested the hypothesis that CBF and CBV are reduced and MTT is prolonged, in both regions during propofol anesthesia and indomethacin administration compared with propofol alone. Methods The authors studied eight patients subjected to craniotomy under propofol-fentanyl anesthesia for supratentorial brain tumors. Magnetic resonance imaging, including perfusion- and diffusion-weighted and structural sequences, was performed (1) on the day before surgery, (2) before and (3) after administration of indomethacin in the propofol-fentanyl anesthetized patient, and (4) 2 days after surgery. Maps of CBF, CBV, and MTT were calculated. The regions of interest were peritumoral gray matter and opposite contralateral gray matter. Analysis of variance was used to analyze flow data. Results Propofol anesthesia was associated with a median 32% (range, 3-61%) and 47% (range, 17-67%) reduction in CBF in the peritumoral and contralateral regions, respectively.The interaction between intervention with propofol and indomethacin and region of interest was not significant for any flow modalities. Neither intervention nor region was significant for MTT, CBF, and CBV (P > 0.05). Conclusion The CBF, CBV, and MTT responses to propofol and indomethacin are not different in the peritumoral region compared with contralateral brain tissue. Indomethacin did not further influence regional CBF, CBV, and MTT during propofol anesthesia.

Effects of graded hypotension on cerebral blood flow, blood volume, and mean transit time in dogs

1992 ◽  
Vol 262 (6) ◽  
pp. H1908-H1914 ◽  
Author(s):  
M. Ferrari ◽  
D. A. Wilson ◽  
D. F. Hanley ◽  
R. J. Traystman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Perfusion Pressure ◽  
Blood Volume ◽  
Transit Time ◽  
Cerebral Perfusion ◽  
Pressure Range ◽  
Cerebral Blood Volume ◽  
Perfusion Pressure ◽  
Mean Transit Time

This study tested the hypothesis that cerebral blood flow (CBF) is maintained by vasodilation, which manifests itself as a progressive increase in mean transit time (MTT) and cerebral blood volume (CBV) when cerebral perfusion pressure is reduced. Cerebral perfusion pressure was decreased in 10 pentobarbital-anesthetized dogs by controlled hemorrhage. Microsphere-determined CBF was autoregulated in all tested cerebral regions over the 40- to 130-mmHg cerebral perfusion pressure range but decreased by 50% at approximately 30 mmHg. MTT and CBV progressively and proportionately increased in the right parietal cerebral cortex over the 40- to 130-mmHg cerebral perfusion pressure range. Total hemoglobin content (Hb1), measured in the same area by an optical method, increased in parallel with the increases in CBV computed as the (CBF.MTT) product. At 30 mmHg cerebral perfusion pressure, CBV and Hb were still increased and MTT was disproportionately lengthened (690% of control). We conclude that within the autoregulatory range, CBF constancy is maintained by both increased CBV and MTT. Outside the autoregulatory range, substantial prolongation of the MTT occurs. When CBV is maximal, further reductions in cerebral perfusion pressure produce disproportionate increases in MTT that signal the loss of cerebral vascular dilatory hemodynamic reserve.

Hyperacute Stroke: Simultaneous Measurement of Relative Cerebral Blood Volume, Relative Cerebral Blood Flow, and Mean Tissue Transit Time

Radiology ◽  
1999 ◽  
Vol 210 (2) ◽  
pp. 519-527 ◽  
Author(s):  
A. Gregory Sorensen ◽  
William A. Copen ◽  
Leif Østergaard ◽  
Ferdinando S. Buonanno ◽  
R. Gilberto Gonzalez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Volume ◽  
Transit Time ◽  
Simultaneous Measurement ◽  
Cerebral Blood Volume ◽  
Hyperacute Stroke ◽  
Relative Cerebral Blood Volume

Early changes measured by magnetic resonance imaging in cerebral blood flow, blood volume, and blood-brain barrier permeability following dexamethasone treatment in patients with brain tumors

1999 ◽  
Vol 90 (2) ◽  
pp. 300-305 ◽  
Author(s):  
Leif Østergaard ◽  
Fred H. Hochberg ◽  
James D. Rabinov ◽  
A. Gregory Sorensen ◽  
Michael Lev ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Brain Tumors ◽  
Mr Imaging ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Clinical Effects ◽  
Content Type ◽  
Fine Print

Object. In this study the authors assessed the early changes in brain tumor physiology associated with glucocorticoid administration. Glucocorticoids have a dramatic effect on symptoms in patients with brain tumors over a time scale ranging from minutes to a few hours. Previous studies have indicated that glucocorticoids may act either by decreasing cerebral blood volume (CBV) or blood-tumor barrier (BTB) permeability and thereby the degree of vasogenic edema.Methods. Using magnetic resonance (MR) imaging, the authors examined the acute changes in CBV, cerebral blood flow (CBF), and BTB permeability to gadolinium-diethylenetriamine pentaacetic acid after administration of dexamethasone in six patients with brain tumors. In patients with acute decreases in BTB permeability after dexamethasone administration, changes in the degree of edema were assessed using the apparent diffusion coefficient of water.Conclusions. Dexamethasone was found to cause a dramatic decrease in BTB permeability and regional CBV but no significant changes in CBF or the degree of edema. The authors found that MR imaging provides a powerful tool for investigating the pathophysiological changes associated with the clinical effects of glucocorticoids.

scholarly journals Relation between Relative Cerebral Blood Flow, Relative Cerebral Blood Volume, and Mean Transit Time in Patients with Acute Ischemic Stroke Determined by Perfusion-Weighted MRI

2003 ◽  
Vol 23 (5) ◽  
pp. 605-611 ◽  
Author(s):  
Oliver C. Singer ◽  
Richard du Mesnil de Rochemont ◽  
Christian Foerch ◽  
Astrid Stengel ◽  
Heiner Lanfermann ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Resonance Imaging ◽  
Unaffected Side ◽  
Weighted Magnetic Resonance Imaging

The relation between relative cerebral blood flow (relCBF), relative cerebral blood volume (relCBV), and mean transit time (MTT) changes was examined in 20 patients with acute cerebral ischemia (<6 h) using perfusion-weighted magnetic resonance imaging. Regions of interest (ROI) were selected on MTT maps covering the entire MTT abnormal cortical area. These ROIs were transferred to the relCBF and relCBV maps to analyze the relation between relCBF, relCBV, and MTT on a voxel-by-voxel basis. On the unaffected side, a tight coupling of relCBF and relCBV was found with little variation of MTT. In hypoperfused cortex, relCBV was increased at all investigated relCBF categories, and there was greater relCBV variability than on the unaffected side. Only a severe decrease of relCBF, to less than 0.3, in comparison with the unaffected side was associated with a reduction of relCBV less than 1.0. In contrast to the unaffected side, a power law function (relCBV = 2.283 × relCBF0.549) resulted in a better fit than using a linear function for the correlation of relCBF and relCBV. MTT ratios increased steadily with decreasing CBF values. In conclusion, there is a clear relation between different perfusion-weighted magnetic resonance imaging parameters in acute ischemia, reflecting both the degree of hemodynamic failure as well as compensatory mechanisms including vasodilation.

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