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Global and regional cerebral blood flow

Noninvasive quantitation in patients with subarachnoid hemorrhage

Maria Granowska, Keith E. Britton, F. Afshar, Charles W. Wright, Richard R. J. Smyth, Ting Y. Lee, and Cyril C. Nimmon

T he rupture of an intracranial aneurysm is usually associated with alteration or loss of consciousness with or without focal neurological signs. 14 These sequelae are attributed at least in part to alteration in cerebral blood flow (CBF) globally or regionally. 9 Arterial spasm is usually implicated. 18, 21 Subsequent cerebral angiography, an essential but invasive technique required to identify the site and surgical anatomy of the problem, may also be associated with arterial spasm, since the injected high-contrast medium may act as an oxygen

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Martin E. Weinand, L. Philip Carter, Waleed F. El-Saadany, Panayiotis J. Sioutos, David M. Labiner, and Kalarickal J. Oommen

electrocorticography; and video electrocorticographic (ECoG) monitoring with depth, subdural, or epidural electrodes. Recently, there has been a trend in epilepsy centers that perform invasive monitoring to do so less often. 16 Because invasive monitoring is decreasing in surgical candidates, 1, 2, 4–6, 12–14, 16, 23, 26–28, 31, 36–39, 43, 44 there is need to improve our understanding of other pathophysiology that might be amenable to noninvasive detection. Localization of the epileptic focus using cerebral blood flow (CBF) methods is supported by the observation that SPECT

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Ian H. Johnston and A. M. Harper

H yperosmolar solutions such as mannitol and urea are widely used in neurosurgical practice, both in the control of raised intracranial pressure and for the reduction of brain bulk at operation to facilitate access. Previous studies of the effects of such solutions on cerebral blood flow have given conflicting results. 1, 5 Changes in cerebral blood flow due to infusion of hyperosmolar solutions could be of considerable clinical importance in states of raised intracranial pressure, as emphasized by the recent suggestion that they may increase an already high

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K. C. Petruk, G. R. West, M. R. Marriott, J. W. McIntyre, T. R. Overtone, and Bryce K. A. Weir

T he pathophysiologic mechanisms involved in the production of decreased cerebral perfusion following subarachnoid hemorrhage (SAH) in man remain obscure. Cerebral arterial spasm has been implicated as the principal cause of morbidity and mortality after aneurysmal rupture. 1, 3, 6, 18, 33 While marked vasospasm appears to diminish cerebral blood flow, the relationship is not fully resolved. Recent clinical and experimental studies 5, 15, 35–38, 40 have failed to show a direct correlation between vasospasm, cerebral ischemia, and neurological sequelae

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J. Douglas Miller, Albert E. Stanek, and Thomas W. Langfitt

D uring expansion of an intracranial mass lesion, several processes occur simultaneously. Brain adjacent to the expanding lesion is distorted, brain shift and herniation occur at a distance from the lesion, 36 and the general level of intracranial pressure (ICP) increases as compensatory mechanisms become exhausted. 17 In addition, the compressed brain may swell. 12 The final effect of such a lesion on regional and total cerebral blood flow (CBF) may therefore be complex and difficult to interpret. In a previous study 24, 25 we used a simple experimental

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Jack M. Fein and Guy Molinari

occlusion and has been reported in 115 selected cases. 1 While the clinical and radiographie indications for this procedure are currently under investigation, the assumption that such grafting techniques will augment cerebral blood flow has not been established. The canine experimental model has been useful in developing the technique of superficial temporal-to-cortical artery anastomosis because of the size of the middle cerebral vessels. Angiographic evaluation postoperatively has been of particular value in documenting patency which, however, is not necessarily

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Francis W. Gamache Jr., Ronald E. Myers, and Esteban Monell

A lthough episodes of spontaneous or controlled hypotension are familiar to all clinicians, little is known about the changes that occur in the overall cerebral blood flow (CBF) or in the blood flow to specific brain regions either during or after such episodes. The local cerebral blood flow (L-CBF) refers to that which is distributed to individual neuroanatomic structures as compared to regional blood flow which is most commonly measured by determining the washout curves of gamma emitters detected by probes placed on the surface of poorly delimited, three

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M. Peter Heilbrun, Jes Olesen, and Niels A. Lassen

A bnormal cerebral blood flow has been found in patients with subarachnoid hemorrhage (SAH). 7, 19 The present study was undertaken to analyze further the regional changes in cerebral circulation that occur in this group of patients and to study the reactivity of the cerebral resistance vessels particularly in relation to the complications of spasm and hydrocephalus. Method Recording of Cerebral Blood Flow (CBF) The 133 xenon intra-arterial method of measuring regional cerebral blood flow (rCBF) has been described previously. 9, 11, 20 In summary

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Howard Yonas, Holly A. Smith, Susan R. Durham, Susan L. Pentheny, and David W. Johnson

T he role played by compromised cerebral hemodynamics in the likelihood of subsequent infarction has not been clearly defined. 1, 3, 5, 22, 24 Until recently, it has not been possible to properly identify significant numbers of individuals who may be at increased hemodynamic risk for infarction. This is due in part to our inability to identify and accurately measure relevant physiological parameters. 21 With the availability of positron emission tomography (PET), which provides an integrated assessment of cerebral blood flow (CBF), blood volume, oxygen

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Jun Harada, Akira Takaku, Shunro Endo, Naoya Kuwayama, and Osamu Fukuda

C hildren sometimes exhibit a surprising ability to recover from neurological impairments caused by cerebrovascular events. On the other hand, once irreversible damage has occurred, they suffer severe sequelae such as delays in mental and motor development. Clarification of the critical levels for ischemia in the developing brain is indispensable in an effort to better understand cerebrovascular disorders in children. Many reports, both clinical and experimental, have been published on the critical level of cerebral blood flow (CBF) during cerebral ischemia