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Effect of hypoglycemia on postischemic cortical blood flow, hypercapnic reactivity, and interstitial adenosine concentration

Young-Baeg Kim, Jeffrey M. Gidday, Ernesto R. Gonzales, Aarti R. Shah, and T. S. Park

T he incidence of perinatal asphyxia 23 and hypoglycemia 8, 48 remains high, and in many instances, asphyxic episodes secondary to cardiopulmonary disorders or birthing complications occur in hypoglycemic neonates. 29 Hypoglycemia can exacerbate hypoxic-ischemic brain injury in neonates, 43, 47 contrary to findings in adults. 24, 44, 46 Also, hypoglycemic ischemia causes greater metabolic derangements than normoglycemic ischemia. 42 Thus, one might predict that ischemia-induced alterations in cerebral blood flow (CBF) and cerebrovascular reactivity would

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Agreement of novel hemodynamic imaging parameters for the acute and chronic stages of ischemic stroke: a matched-pair cohort study

Martina Sebök, Christiaan Hendrik Bas van Niftrik, Susanne Wegener, Andreas Luft, Luca Regli, and Jorn Fierstra

T o advance ischemic stroke care, clinically versatile imaging parameters to identify patients with symptomatic cerebrovascular steno-occlusive disease at highest risk for recurrent stroke are strongly desired. 1 Although increased oxygen extraction fraction from PET and impaired cerebrovascular reactivity (CVR) from xenon-CT and SPECT have been strongly associated with recurrent stroke risk, 2–5 these imaging modalities are not feasible for routine clinical stroke imaging. To address this well-known challenge, we have recently validated two emerging

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More pronounced hemodynamic alterations in patients with brain arteriovenous malformation–associated epilepsy

Martina Sebök, Menno Robbert Germans, Christiaan Hendrik Bas van Niftrik, Zsolt Kulcsár, Luca Regli, and Jorn Fierstra

may play an etiological role, 7 , 10 whereas others have raised the possibility that seizures are more often related to a disrupted venous outflow pattern. 11–13 However, these hemodynamic patterns remain challenging to demonstrate quantitatively. Blood oxygenation level–dependent (BOLD) cerebrovascular reactivity (CVR) mapping is an emerging hemodynamic imaging method that can quantitatively measure an arterial steal phenomenon (as a paradoxical BOLD signal decrease during a vasodilatory stimulus, resulting in a negative CVR response). 14–16 Furthermore, a

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Continuous monitoring of cerebrovascular pressure reactivity in patients with head injury

Christian Zweifel, Andrea Lavinio, Luzius A. Steiner, Danila Radolovich, Peter Smielewski, Ivan Timofeev, Magdalena Hiler, Marcella Balestreri, Peter J. Kirkpatrick, John D. Pickard, Peter Hutchinson, and Marek Czosnyka

( Fig. 5 ); this finding supports the assumption of the contribution of PRx to patient outcome. F ig . 4. Graphs of the relationship between the rate of favorable outcome, mortality rate, and PRx in a cohort of 398 patients with head injuries with continuous monitoring ( dots represent mean values). Upper : The PRx indicating worse cerebrovascular reactivity (becoming more positive) reduced the rate of favorable outcome uniformly. Lower : The mortality rate increased abruptly to > 50% when the PRx became radically positive (> 0.35). F ig . 5

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Effect of stable xenon inhalation on intracranial pressure during measurement of cerebral blood flow in head injury

Jan Plougmann, Jens Astrup, Jens Pedersen, and Carsten Gyldensted

degree of disturbances in cerebrovascular reactivity. It is possible that patient medication may influence and possibly block part of the effects of xenon on CBF and metabolism. Variations in patient medication may explain the fact that minimal or no effect of xenon inhalation on ICP was observed in some studies. 3, 13 However, lack of detailed information about patient medication makes a comparison between the studies impossible. None of our patients received any kind of benzodiazepines or muscle relaxant drugs. Conclusions We conclude that xenon

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Post-carotid endarterectomy changes in cerebral glucose metabolism on 18F-fluorodeoxyglucose positron emission tomography associated with postoperative improvement or impairment in cognitive function

Koji Yoshida, Kuniaki Ogasawara, Hiroaki Saura, Hideo Saito, Masakazu Kobayashi, Kenji Yoshida, Kazunori Terasaki, Shunrou Fujiwara, and Akira Ogawa

voluntary provision of written informed consent. Finally, according to the preoperative brain perfusion SPECT criteria described below, patients who had reduced cerebrovascular reactivity (CVR) to acetazolamide in the cerebral hemisphere ipsilateral to surgery were entered into the present study. Patients meeting the following criteria were excluded from the present study: development of further ischemic symptoms during the period between initial evaluation and surgical intervention; new neurological deficits lasting ≥ 2 months after surgery; or additional ischemic

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The efficacy of superficial temporal artery–middle cerebral artery anastomosis in patients with moyamoya disease complaining of severe headache

Clinical article

Yoshikazu Okada, Takakazu Kawamata, Akitsugu Kawashima, Kohji Yamaguchi, Yuko Ono, and Tomokatsu Hori

Object

Some patients with moyamoya disease complain of severe headache, which may be closely related to cerebral ischemia. The efficacy of superficial temporal artery–middle cerebral artery (STA-MCA) anastomosis in these patients was evaluated by clinicoradiological studies.

Methods

Of 117 consecutive patients with ischemic moyamoya disease, 25 complained mainly of severe headache (headache group) and 92 had no significant headache (nonheadache group). Intensity of headache was evaluated pre- and postoperatively. Furthermore, regional cerebral blood flow (rCBF) and cerebrovascular reactivity (CVR) were assessed pre- and postoperatively.

Results

The headache group was significantly younger than the nonheadache group. In a group corrected for the age distribution, preoperative rCBF and CVR were similar in headache and nonheadache groups. After STA-MCA anastomosis, 16 patients with headache experienced complete relief from headache, 7 patients showed remarkable improvements and discontinued medications for headache, and the remaining 2 patients had some alleviation of headache but sometimes required medication. In the headache group, the postoperative rCBF was significantly greater than the preoperative value. The postoperative rCBF in this group was also significantly greater than the postoperative rCBF in the nonheadache group.

Conclusions

These data suggest that severe headache is one of the main symptoms in young patients with moyamoya disease probably related to cerebral circulatory disturbances. An STA-MCA anastomosis is effective in relieving headache in patients with ischemic moyamoya disease manifesting severe headache, probably by improving perfusion pressure and cerebral circulation.

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Analysis of the cerebrospinal fluid pulse wave in intracranial pressure

Erico R. Cardoso, Jack O. Rowan, and Sam Galbraith

✓ The configuration of the intracranial pressure (ICP) pulse wave represents a complex sum of various components. Amplitude variations of an isolated component might reflect changes in a specific intracranial structure. Fifteen awake patients suffering from hydrocephalus, benign intracranial hypertension, or head injury underwent ICP monitoring through a ventricular catheter and were subjected to three standardized maneuvers to alter the intracranial dynamics: head elevation, voluntary hyperventilation, and cerebrospinal fluid (CSF) withdrawal. A 12° head elevation and fractionated CSF withdrawal caused a mild ICP drop and a proportionate amplitude reduction of all the wave components. Voluntary hyperventilation caused a comparable fall in ICP, and a disproportionate reduction in the amplitude of the wave components, especially the P2 component. It is postulated that the decrease in amplitude of the P2 component reflects the reduction of the cerebral bulk caused by hyperventilation. Head elevation and CSF withdrawal caused a decrease of global ICP but no specific changes in any intracranial structure, and consequently the configuration of the pulse wave remained unchanged. The establishment of relationships between anatomical substrate and particular wave components is promising since potentially it could be useful for monitoring conditions such as vasoparalysis, impaired cerebrovascular reactivity, and cerebral edema.

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Letter to the Editor

Normal-pressure hydrocephalus and cerebral blood flow

Nikolaos Sakellaridis and Stavros Stavropoulos

T o T he E ditor : We would like to make a comment on a recently published article by Chang et al. (Chang CC, Asada H, Mimura T, et al: A prospective study of cerebral blood flow and cerebrovascular reactivity to acetazolamide in 162 patients with idiopathic normal-pressure hydrocephalus. Clinical article. J Neurosurg 111: 610–617, September, 2009). One of the major conclusions of this interesting article, as described by the authors in the summary, is that “preoperative CVR [cerebrovascular reactivity] was significantly impaired . . . in responders

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Editorial: Patient-specific intracranial pressure

Oren Sagher

additional, expensive, and untested measures, Dr. Lazaridis' group has proposed an analysis of currently collected physiological parameters that instead takes into account variations in arterial blood pressure to arrive at an index of cerebrovascular reactivity. This approach is rooted in the observation that patients seem to fare better when ICP changes happen slowly and cerebrovascular reactivity remains normal. It has long been observed that patients with chronic increases in ICP (for example, due to slow-growing tumors, pseudotumor, and hydrocephalus) are often