Cerebral hemodynamic

Nabavi DG, Cenic A, Dool J, Smith RM, Espinosa F, Craen RA, Gelb AW, Lee TY. Quantitative assessment of cerebral hemodynamics using CT stability, accuracy, and precision studies in dogs. J Comput Assist Tomogr 1999 23 506-515. 

Endo H, Inoue T, Ogasawara K, Fukuda T, Kanbara Y, Qgawa A. Quantitative assessment of cerebral hemodynamics using perfusion-weighted MRI in patients with major cerebral artery occlusive disease comparison with positron emission tomography. Stroke 2006 37 388-392. 

Vincamine (91) is the major alkaloid of V. minor, a plant used against headache and vertigo. It exerts a sedative CNS action and produces a fall in blood pressure. The principal activity is a moderate cerebral vasodilation. Clinical studies have demonstrated that i.v. administration of 91 to humans reduces the arterial blood pressure and increases cerebral blood flow and oxygen consumption. The improved cerebral hemodynamic conditions significantly and positively affect the state of patients with advanced arteriosclerosis with beneficial effects on memory, concentration, and behavior. It has thereafter been introduced under several trade names as a pharmaceutical in many European countries (232). Vobasine (32) has been widely studied it exhibits a weak CNS depressive, analgesic, and antipyretic action (21). 

C. E. Elwell, R. Springett, E. Hillman, and D. T. Delpy. Oscillations in cerebral hemodynamics, implications for functional activation studies. Advances in Experimental and Medical Biology, 471 57-65, 1999. 

J. H. Meek, C. E. Elwell, M. J. Khan, J. Romaya, J. D. Wyatt, D. T. Delpy, and S. Zeki. Regional changes in cerebral hemodynamics as a result of a visual stimulus measured by near infrared spectroscopy. Proceedings of Royal Society of London, 261 351-356, 1995. 

H. Obrig, M. Neufang, R. Wenzel, M. Kohl, J. Steinbrink, K. Einhaupl, and A. Villringer. Spontaneous low frequency oscillations of cerebral hemodynamics and metabolism in human adults. Neuroimage, 12 623-639, 2000. 

V. Toronov, A. Webb, J. H. Choi, M. Wolf, L. Safonova, U. Wolf, and E. Grat-ton. Study of local cerebral hemodynamics by frequency-domain near-infrared spectroscopy and correlation with simultaneously acquired functional magnetic resonance imaging. Optics Express, 9 417-427, 2001. 

Alvarez, X.A., Pichel, V., Perez, P., et al. (2000) Double-blind, randomized, placebo-control-led pilot study with anapsos in senile dementia effects on cognition, brain bioelectrical activity and cerebral hemodynamics. Meth. Eind. Exp. Clin. Pharmacol., 22, 585-594. 

Six unselected patients (four women), mean age 27 years, with acute liver failure and grade IV hepatic encephalopathy received terlipressin 0.005 mg/kg as a single intravenous bolus (16). There was an increase in cerebral blood flow 1 hour after the bolus, which returned to baseline at 5 hours, and an increase in intracranial pressure at 1 hour, which returned to baseline at 2 hours. The authors speculated that terlipressin could have a deleterious effect on cerebral hemodynamics in patients with severe hepatic encephalopathy. 

While rMTT can depict changes in cerebral hemodynamics, which are due to vessel occlusion of cerebral arteries and the respective compensation mechanisms, the time to arrival of contrast (TTA) is sensitive to vessel diseases, which are more upstream of the arterial flow, most commonly high grade stenoses or occlusions of the carotid arteries. In such patients, blood flow in the hemisphere ipsilateral to the stenosis is mainly supplied by the contralateral carotid artery via the circle of Willis. Due to this detour, TTA is prolonged in the ipsilateral hemisphere (Reith et al. 1997). At the same time, rMTT may be prolonged in the ipsilateral hemisphere resulting from decreased blood flow (Dorfler et al. 2001). If TTP is calculated instead of MTT, the effect of the bolus delay cannot be separated from that of the perfusion decrease, because TTP is influenced by both rMTT and TTA. 

Soinne L, Helenius J, Tatlisumak T, Saimanen E, Salonen O, Lindsberg PJ, Kaste M (2003b) Cerebral hemodynamics in asymptomatic and symptomatic patients with high-grade carotid stenosis undergoing carotid endarterectomy. Stroke 34 1655-1661... 

Meyer J. S., Kondo A., Nomura F., Sakamoto K., and Teraura T. (1970) Cerebral hemodynamics and metabolism following experimental head inj ury. J. Neuro surg. 32,304-319. 

Stone H. H., Donnelly C., and Frobese A. S. (1956) The effect of lowered body temperature on the cerebral hemodynamics and metabolism of man. Surg. Gynecol. Obstet. 103, 313-322. 

The cause of cocaine-related stroke and transient ischemic attacks has been studied by transcranial Doppler sonography, a continuous measure of cerebral blood flow velocity, to monitor the course of cerebral hemodynamic changes during acute intravenous injection of placebo, and of cocaine 10, 25, and 50 mg in seven cocaine abusers (150). There was a significant increase in mean and systolic velocity (lasting about 2 minutes) with all doses of cocaine but not with placebo. Cocaine produced an immediate brief period of vasoconstriction... 

In a small comparison of ibuprofen and indometacin in preterm infants with patent ductus arteriosus there was no apparent difference in the rate of patent ductus arteriosus closure ibuprofen did not impair cerebral hemodynamics or oxygenation, while indometacin impaired cerebral oxygen delivery (4). 

Albanese J, Viviand X, Potie F, Rey M, Alliez B, Martin C. Sufentanil, fentanyl, and alfentanil in head trauma patients a study on cerebral hemodynamics. Crit Care Med 1999 27(2) 407-11. 

Chow et al., The Relation Between Pump Flow Rate and Pul-satility on Cerebral Hemodynamics During Pediatric Cardiopulmonary Bypass, J. Thoracic Cardiovasc. Surg., 114(4), 1123 (1997). 

V. Toronov, M. A. Franceschini, M. Filiaci, S. Fantini, M. Wolf, A Michalos, and E. Gratton, Near-Infrared Study of Fluctuations in Cerebral Hemodynamics During Rest and Motor Stimulation Temporal Analysis and Spatial Mapping, Med. Phys., 27(4), 801-815 (2000). 

W. S. Park and Y. S. Chang, Effects of Decreased Cerebral Perfusion Pressure on Cerebral Hemodynamics, Brain Cell Membrane Function, and Energy Metabolism During the Early Phase of Experimental Escherichia coli Meningitis in the Newborn Piglet, Neurological Res., 21(3), 345-367... 

Martin NA, Patwardhan RV, Alexander MJ, et al. Characterization of cerebral hemodynamic phases following severe head trauma Hypoperfusion, hyperemia, and vasospasm. J Neurosurg 1997 87 9-19. 

Settakis G, Lengyel A, Molnar C, et al. Transcranial Doppler study of the cerebral hemodynamic changes during breathholding and hyperventilation tests. J Neuroimaging 2002 12 252-8. 

Liu, Y., et al.. Cerebral hemodynamics in human acute ischemic stroke a study with diffusion- and perfusion-weighted magnetic resonance imaging and SPECT. J Cereb Blood Flow Metab, 2000. 20(6) p. 910-20. 

As Tmax and TTP are only indirectly related to cerebral hemodynamics, it is more difficult to describe how these parameters are altered in ischemic conditions. In general, blood usually reaches underperfused tissue via stenotic vessels that reduce flow and delay bolus arrival, and/or via indirect collateral vessels that increase the time needed to reach the tissue, hi either case, the arrival of the injected contrast bolus is delayed, and Tmax is usually increased in underperfused tissue. However, Tmax is also increased in the tissue that is perfused by collateral pathways that are successful in maintaining normal blood flow to the tissue whose... 

Powers WJ. Cerebral hemodynamics in ischemic cerebrovascular disease. Ann Neurol. 1991 29 231-240... 

As described in previous chapters, MR and CTP imaging are dynamic contrast methods, whereby postprocessing of the source images produces a series of maps that describe the cerebral hemodynamics. Importantly, postprocessing can be performed in various ways and may yield different results for the same source perfusion data... 

HashimotoN (2001) Microsurgery for cerebral arteriovenous malformations a dissection technique and its theoretical implications. Neurosurgery 48 1278-1281 Hashimoto N, Emala CW, Joshi S, Mesa-Tejada R et al. (2001) Abnormal pattern of Tie-2 and vascular endothelial growth factor receptor expression in human cerebral arteriovenous malformations. Neurosurgery 47 910-918 Hassler W, Steinmetz H (1987) Cerebral hemodynamics in angioma patients an intraoperative study. J Neurosurg 67 822-831... 

Takano K, Utsunomiya H, Ono H et al. (1999) Dynamic contrast-enhanced subtraction MR angiography in intracranial vascular abnormalities. Eur Radiol 9 1909-1912 Takeuchi S, Kikuchi H, Karasawa J, Naruo Y et al. (1987) Cerebral hemodynamics in arteriovenous malformations evaluation by single-photon emission CT. AJNR Am J Neuroradiol 8 193-197... 

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