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Response of cerebral blood flow and cerebrovascular reactivity to acetazolamide in patients with dementia and idiopathic normal-pressure hydrocephalus

Chia-Cheng Chang, Nobumasa Kuwana, Susumu Ito, and Tadashi Ikegami

The responses of cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to administration of acetazolamide were investigated in 16 patients with dementia and ventriculomegaly to clarify the cerebral hemodynamics in patients with idiopathic normal-pressure hydrocephalus (NPH).

The mean CBF velocity in the whole brain was measured by the Patlak plot method by using technetium-99m hexamethylpropyleneamine oxime single-photon emission computerized tomography. The CVR values were obtained from the response to administration of 500 mg of acetazolamide and calculated as the percentage of change from the baseline mean CBF value. The mean CBF value was significantly reduced (p < 0.01) in six patients with (35.2 ± 5 ml/100 g/minute) and 10 patients without (33.5 ± 2.8 ml/100 g/minute) NPH compared with the age-matched normal controls (40.8 ± 3.2 ml/100 g/minute), showing no significant difference. The CVR was significantly impaired in patients with NPH (0.8 ± 1.7%; p < 0.001), whereas in patients without NPH preserved CVR (11.3 ± 3%) was demonstrated compared with the normal controls (14.7 ± 1.1%). In patients with NPH a significantly lower CVR (p < 0.001) was shown than in those without NPH. The CVR significantly increased (p < 0.001) after placement of a shunt in patients with NPH.

Reductions in both CBF and CVR may be diagnostic indicators of NPH in patients with dementia in whom ventriculomegaly is present. In patients with dementia and idiopathic NPH both reduced CBF and extremely impaired CVR are shown. The results of the present study suggest that ischemia due to the process of NPH is responsible for the reduction of CBF and manifestation of symptoms in patients with idiopathic NPH.

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Feasibility and safety of intraoperative BOLD functional MRI cerebrovascular reactivity to evaluate extracranial-to-intracranial bypass efficacy

Giovanni Muscas, Christiaan Hendrik Bas van Niftrik, Jorn Fierstra, Marco Piccirelli, Martina Sebök, Jan-Karl Burkhardt, Antonios Valavanis, Athina Pangalu, Luca Regli, and Oliver Bozinov

, 23 or cerebrovascular reactivity (CVR). 11 , 15 The application of intraoperative high-field MRI may deliver such information directly after the bypass anastomosis. By obtaining functional MRI blood oxygenation level–dependent (BOLD) volumes during repeated cycles of apnea, CVR can be measured at the brain tissue level. We previously reported the feasibility of intraoperative 3-T MRI BOLD-CVR and its preliminary application for neurovascular surgery. 6 The purpose of this study was to assess whether intraoperative BOLD-CVR can offer hemodynamic information at the

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Novel index for predicting mortality during the first 24 hours after traumatic brain injury

Hakseung Kim, Hack-Jin Lee, Young-Tak Kim, Yunsik Son, Peter Smielewski, Marek Czosnyka, and Dong-Joo Kim

study, we speculated that the extent of hypoperfusion would be reflected by a specifically designed parameter that incorporates the combined status of hypotension, intracranial hypertension, and cerebrovascular reactivity. In addition, this study tested the prognostic capacity of this parameter during the first 24 hours of ICP monitoring. Methods This study investigated the association between the duration of cerebral hypoperfusion and mortality in TBI patients during the first 24 hours of neurocritical care unit (NCCU) admission. Cerebral hypoperfusion events were

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Flow augmentation STA-MCA bypass evaluation for patients with acute stroke and unilateral large vessel occlusion: a proposal for an urgent bypass flowchart

Martina Sebök, Giuseppe Esposito, Christiaan Hendrik Bas van Niftrik, Jorn Fierstra, Tilman Schubert, Susanne Wegener, Jeremia Held, Zsolt Kulcsár, Andreas R. Luft, and Luca Regli

found only 16 level IV studies and 3 level III studies. This lack of evidence encouraged further research to explore the use of flow augmentation bypass in the management of acute ischemic stroke. A major challenge is adequate identification of patients with persistent hypoperfusion and insufficient collateral flow in the setting of acute stroke who will benefit from microsurgical revascularization. 13 In this regard, blood oxygenation level–dependent functional MRI (BOLD fMRI) of cerebrovascular reactivity (CVR) is known as an efficient tool for studying cerebral

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Contemporary and emerging magnetic resonance imaging methods for evaluation of moyamoya disease

Vance T. Lehman, Petrice M. Cogswell, Lorenzo Rinaldo, Waleed Brinjikji, John Huston III, James P. Klaas, and Giuseppe Lanzino

the assessment of MMD has been extensively investigated. 21 , 22 , 28 , 43 , 48 , 63 The “ivy sign,” an indicator of slow or retrograde flow in cortical vessels, can help characterize the origins of collateral supply, correlates with cerebrovascular reactivity (CVR), and can improve in response to revascularization surgery, or it can temporarily worsen after revascularization in the setting of hyperperfusion. 21 , 28 , 48 In the cerebral white matter, linear T2 hyperintense streaks perpendicular to the lateral ventricle, referred to as “medullary streaks,” have

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The contribution of imaging in diagnosis, preoperative assessment, and follow-up of moyamoya disease

A review

Susanna Bacigaluppi, Amir R. Dehdashti, Ronit Agid, Timo Krings, Michael Tymianski, and David J. Mikulis

disease . AJNR Am J Neuroradiol 20 : 1836 – 1838 , 1999 50 Maeda M , Yagishita A , Yamamoto T , Sakuma H , Takeda K : Abnormal hyperintensity within the subarachnoid space evaluated by fluid-attenuated inversion-recovery MR imaging: a spectrum of central nervous system diseases . Eur Radiol 13 : 4 Suppl L192 – L201 , 2003 10.1007/s00330-003-1877-9 51 Mandell DM , Han JS , Poublanc J , Crawley AP , Stainsby JA , Fisher JA , : Mapping cerebrovascular reactivity using blood oxygen level-dependent MRI in patients with arterial

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Intracranial Pressure: More Than a Number

Marek Czosnyka, Peter Smielewski, Ivan Timofeev, Andrea Lavinio, Eric Guazzo, Peter Hutchinson, and John D. Pickard

✓Many doctors involved in the critical care of head-injured patients understand intracranial pressure (ICP) as a number, characterizing the state of the brain pressure–volume relationships. However, the dynamics of ICP, its waveform, and secondarily derived indices portray useful information about brain homeostasis. There is circumstantial evidence that this information can be used to modify and optimize patients' treatment. Secondary variables, such as pulse amplitude and the magnitude of slow waves, index of compensatory reserve, and pressure–reactivity index (PRx), look promising in clinical practice. The optimal cerebral perfusion pressure (CPP) derived using the PRx is a new concept that may help to avoid excessive use of vasopressors in CPP-oriented therapy. However, the use of secondary ICP indices remains to be confirmed in clinical trials.

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Occipital artery to middle cerebral artery bypass in pediatric moyamoya disease: rescue therapy after failed revascularization

Akikazu Nakamura, Akitsugu Kawashima, Hugo Andrade-Barazarte, Takayuki Funatsu, Juha Hernesniemi, and Takakazu Kawamata

, additional revascularization procedure, symptoms (presence or recurrence), pre- and postoperative cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) changes, PCA stenosis and progression, PCA-related and nonrelated symptoms, and latest follow-up. We evaluated anatomical features regarding PCA stenosis, progression, CBF, and CVR in the 10 hemispheres. FIG. 1. Flow diagram demonstrating the inclusion and exclusion criteria. Radiological Evaluation The patients underwent preoperative MRI, MR angiography (MRA), digital subtraction angiography (DSA), and iodine-123

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Occipital artery to middle cerebral artery bypass in pediatric moyamoya disease: rescue therapy after failed revascularization

Akikazu Nakamura, Akitsugu Kawashima, Hugo Andrade-Barazarte, Takayuki Funatsu, Juha Hernesniemi, and Takakazu Kawamata

revascularization procedure, additional revascularization procedure, symptoms (presence or recurrence), pre- and postoperative cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) changes, PCA stenosis and progression, PCA-related and nonrelated symptoms, and latest follow-up. We evaluated anatomical features regarding PCA stenosis, progression, CBF, and CVR in the 10 hemispheres. FIG. 1. Flow diagram demonstrating the inclusion and exclusion criteria. Radiological Evaluation The patients underwent preoperative MRI, MR angiography (MRA), digital

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The profile of cognitive impairment and hemodynamic compromise in moyamoya: a single-center prospective cohort study

Annick Kronenburg, Pieter T. Deckers, Esther van den Berg, Monique M. van Schooneveld, Evert-Jan Vonken, Albert van der Zwan, Bart N. M. van Berckel, Maqsood Yaqub, Willem Otte, Catharina J. M. Klijn, and Kees P. J. Braun

cognitive impairment. 3 The exact profile of cognitive disturbances in MMV remains to be established, particularly in the Western world. 3 – 8 The [ 15 O]H 2 O-PET technique is used to determine the need for revascularization surgery and to optimize surgical strategy. This technique enables the assessment of regional cerebral blood flow and cerebrovascular reactivity (CVR) after acetazolamide challenge. 1 , 5 To what extent cognitive function is related to hemodynamic compromise remains unclear. Several studies have suggested that frontal hypoperfusion, white matter