-
1.
Regional cerebral effects of ketone body infusion with 3-hydroxybutyrate in humans: Reduced glucose uptake, unchanged oxygen consumption and increased blood flow by positron emission tomography. A randomized, controlled trial.
Svart, M, Gormsen, LC, Hansen, J, Zeidler, D, Gejl, M, Vang, K, Aanerud, J, Moeller, N
PloS one. 2018;(2):e0190556
Abstract
Ketone bodies are neuroprotective in neurological disorders such as epilepsy. We randomly studied nine healthy human subjects twice-with and without continuous infusion of 3-hydroxybutyrate-to define potential underlying mechanisms, assessed regionally (parietal, occipital, temporal, cortical grey, and frontal) by PET scan. During 3-hydroxybutyrate infusions concentrations increased to 5.5±0.4 mmol/l and cerebral glucose utilisation decreased 14%, oxygen consumption remained unchanged, and cerebral blood flow increased 30%. We conclude that acute 3-hydroxybutyrate infusion reduces cerebral glucose uptake and increases cerebral blood flow in all measured brain regions, without detectable effects on cerebral oxygen uptake though oxygen extraction decreased. Increased oxygen supply concomitant with unchanged oxygen utilisation may contribute to the neuroprotective effects of ketone bodies.
-
2.
Absolute perfusion measurements and associated iodinated contrast agent time course in brain metastasis: a study for contrast-enhanced radiotherapy.
Obeid, L, Deman, P, Tessier, A, Balosso, J, Estève, F, Adam, JF
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. 2014;(4):638-45
-
-
Free full text
-
Abstract
Contrast-enhanced radiotherapy is an innovative treatment that combines the selective accumulation of heavy elements in tumors with stereotactic irradiations using medium energy X-rays. The radiation dose enhancement depends on the absolute amount of iodine reached in the tumor and its time course. Quantitative, postinfusion iodine biodistribution and associated brain perfusion parameters were studied in human brain metastasis as key parameters for treatment feasibility and quality. Twelve patients received an intravenous bolus of iodinated contrast agent (CA) (40 mL, 4 mL/s), followed by a steady-state infusion (160 mL, 0.5 mL/s) to ensure stable intratumoral amounts of iodine during the treatment. Absolute iodine concentrations and quantitative perfusion maps were derived from 40 multislice dynamic computed tomography (CT) images of the brain. The postinfusion mean intratumoral iodine concentration (over 30 minutes) reached 1.94 ± 0.12 mg/mL. Reasonable correlations were obtained between these concentrations and the permeability surface area product and the cerebral blood volume. To our knowledge, this is the first quantitative study of CA biodistribution versus time in brain metastasis. The study shows that suitable and stable amounts of iodine can be reached for contrast-enhanced radiotherapy. Moreover, the associated perfusion measurements provide useful information for the patient recruitment and management processes.
-
3.
Combination of preoperative cerebral blood flow and 123I-iomazenil SPECT imaging predicts postoperative cognitive improvement in patients undergoing uncomplicated endarterectomy for unilateral carotid stenosis.
Yamashita, T, Ogasawara, K, Kuroda, H, Suzuki, T, Chida, K, Kobayashi, M, Yoshida, K, Kubo, Y, Ogawa, A
Clinical nuclear medicine. 2012;(2):128-33
Abstract
PURPOSE The purpose of the present study was to determine whether preoperative cerebral blood flow (CBF) or cortical central benzodiazepine receptor binding potential as measured by brain perfusion or (123)I-iomazenil (IMZ) single-photon emission computed tomography (SPECT) imaging, respectively, can predict cognitive improvement after uncomplicated carotid endarterectomy (CEA). METHODS Neuropsychological testing was performed preoperatively and after 1 month postoperatively in 140 patients who underwent CEA for unilateral internal carotid artery (ICA) stenosis (≥ 70%). Brain perfusion SPECT using N-isopropyl-p-[(123)I]-iodoamphetamine and IMZ SPECT was also performed before surgery. SPECT data were analyzed using a 3-dimensional stereotaxic region-of-interest template. RESULTS Fourteen patients (10%) showed improved cognitive function postoperatively. Logistic regression analysis demonstrated that, among the variables tested, low relative CBF in the cerebral hemisphere ipsilateral to surgery was significantly associated with postoperative cognitive improvement (95% confidence interval: 0.623-0.868; P = 0.0003). The combination of reduced relative CBF and moderately reduced relative uptake of IMZ identified development of postoperative cognitive improvement with 100.0% sensitivity, 84.9% specificity, a positive predictive value of 42.4%, and a negative predictive value of 100%. Further, in a subgroup of patients with reduced relative CBF and moderately reduced relative uptake of IMZ, the difference between these 2 values was significantly greater in patients with postoperative cognitive improvement than in those without (P < 0.0001). CONCLUSIONS The combination of preoperative CBF and cortical central benzodiazepine receptor binding potential as determined by SPECT can predict cognitive improvement after CEA.
-
4.
[The application of combined physiotherapeutic methods for the complex treatment of patients with dyscirculatory encephalopathy].
Shiman, AG, Klocheva, EG, Kaiumov, SF, Shoferova, SD, Zhukova, MV
Voprosy kurortologii, fizioterapii, i lechebnoi fizicheskoi kultury. 2012;(2):9-12
Abstract
This article reports the results of applying basic pharmacotherapy (enalapril, cytoflavin) and its combination with physical factors (transcranial electrostimulation, combined application oftranscranial electrostimulation and low-frequency magnetic therapy) in the complex treatment of patients with stage I-II dyscirculatory encephalopathy. The study has demonstrated that the combined treatment with cytoflavin, enalapril, transcranial electrostimulation and low-frequency magnetic therapy produced the most pronounced therapeutic effect (82.5%), as confirmed by positive dynamics of clinical and functional parameters.
-
5.
Acute perfusion changes after spontaneous SAH: a perfusion CT study.
Lagares, A, Cicuendez, M, Ramos, A, Salvador, E, Alén, JF, Kaen, A, Jiménez-Roldán, L, Millán, JM
Acta neurochirurgica. 2012;(3):405-11; discussion 411-2
Abstract
BACKGROUND Perfusion computed tomography (CT) is a rapid technique that allows the measurement of acute disturbances in local and global cerebral blood flow in patients suffering stroke and spontaneous subarachnoid haemorrhage (SAH). The purpose of this study was to establish the relationship between different measures of brain perfusion made on dynamic-contrast CT reconstructions performed as soon as SAH has been diagnosed and the severity of the bleeding determined by the clinical grade, the extent of the bleeding and the outcome of the patients. METHODS After the diagnosis of SAH by conventional CT, a perfusion CT was performed before CT angiography. All imaging studies were performed on a six-slice spiral CT scanner. All images were analysed using perfusion software developed by Philips, which produces perfusion CT quantitative data based on temporal changes in signal intensity during the first pass of a bolus of an iodinated contrast agent. Measurements of mean transient time (MTT), time to peak (TTP), cerebral blood volume (CBV) and cerebral blood flow (CBF) in volumes of interest corresponding to territories perfused by the major cerebral arteries were performed. Different data regarding severity of the bleeding-such as level of consciousness, amount of bleeding in conventional CT-were collected. All poor-grade patients received a ventriculostomy catheter so that ICP recordings were obtained. Also, the occurrence of delayed cerebral ischaemia (DCI) was recorded. Outcome was assessed by the Glasgow Outcome Scale 6 months after the bleeding. For statistical analysis, non-parametric correlations between variables were performed. FINDINGS Thirty-nine patients have been included in the study since January 2007. In SAH patients there are increasing perfusion abnormalities as the severity of the bleeding increases. The most affected perfusion parameters are TTP and MTT, as they significantly increase with the clinical severity of the bleeding and the total volume of bleeding (P < 0.01, Spearman's Rho). When average MTT time is increased over 5.9 s there is a 20-fold (95% CI = 2.1-182) risk of poor outcome. All patients presenting this MTT time suffered from DCI. This value has a positive predictive value of 100% for DCI and 90% for a poor outcome. CONCLUSIONS SAH causes cerebral blood flow abnormalities even in the acute phase of the illness, consisting mainly of an increase in circulation times (TTP and MTT), which are correlated with the severity of the bleeding.
-
6.
Azelnidipine, a long-acting calcium channel blocker, could control hypertension without decreasing cerebral blood flow in post-ischemic stroke patients. A 123I-IMP SPECT follow-up study.
Watanabe, M, Hirano, T, Okamoto, S, Shiraishi, S, Tomiguchi, S, Uchino, M
Hypertension research : official journal of the Japanese Society of Hypertension. 2010;(1):43-8
Abstract
Azelnidipine, a long-acting calcium channel blocker, is highly lipid soluble and selective for the vascular wall, and is expected to have an increasing effect on cerebral blood flow (CBF). The aim of this study is to investigate its safety and efficacy in stroke patients in the chronic stage as far as CBF is concerned using N-isopropyl-p-(123)I-iodo amphetamine ((123)I-IMP) single-photon emission computed tomography (SPECT). The patients were orally administered 8 or 16 mg of azelnidipine. Regional CBF was evaluated by (123)I-IMP SPECT using three-dimensional stereotactic region-of-interest (ROI) template (3D-SRT), a technique using anatomical standardization and ROI template consisting of 636 ROIs for the whole brain. Mean hemispheric CBF was defined as the mean value of the corpus callosum, and the precentral, central, parietal, angular and temporal gyri. Mean hemispheric and regional CBF after 1, 3 and 6 months were analyzed using a one-way repeated-measures analysis of variance. Ten post-ischemic stroke patients with hypertension were enrolled between October 2005 and October 2007, and all of them were well controlled with normal blood pressure (before: 172.3+/-16.6/88.4+/-14.0 mm Hg; 6 months: 128.7+/-15.9/70.9+/-10.1 mm Hg). No vascular events were observed during the study period. The mean hemispheric CBF was maintained during the study period (before: 46.0+/-9.7 ml per 100 g per min; 6 months: 49.3+/-11.1 ml per 100 g per min). The regional CBF was also maintained. In the chronic stage of ischemic stroke, azelnidipine could safely decrease systemic blood pressure without decreasing CBF.
-
7.
Hypertonic saline and its effect on intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen.
Rockswold, GL, Solid, CA, Paredes-Andrade, E, Rockswold, SB, Jancik, JT, Quickel, RR
Neurosurgery. 2009;(6):1035-41; discussion 1041-2
Abstract
OBJECTIVE Hypertonic saline is emerging as a potentially effective single osmotic agent for control of acute elevations in intracranial pressure (ICP) caused by severe traumatic brain injury. This study examines its effect on ICP, cerebral perfusion pressure (CPP), and brain tissue oxygen tension (PbtO2). METHODS Twenty-five consecutive patients with severe traumatic brain injury who were treated with 23.4% NaCl for elevated ICP were evaluated. Bolt catheter probes were placed in the noninjured hemisphere, and hourly ICP, mean arterial pressure, CPP, and PbtO2 values were recorded. Thirty milliliters of 23.4% NaCl was infused over 15 minutes for intracranial hypertension, defined as ICP greater than 20 mm Hg. Twenty-one male patients and 4 female patients aged 16 to 64 years were included. The mean presenting Glasgow Coma Scale score was 5.7. RESULTS Mean pretreatment values included an ICP level of 25.9 mm Hg and a PbtO2 value of 32 mm Hg. The posttreatment ICP level was decreased by a mean of 8.3 mm Hg (P < 0.0001), and there was an improvement in PbtO2 of 3.1 mm Hg (P < 0.01). ICP of more than 31 mm Hg decreased by 14.2 mm Hg. Pretreatment CPP values of less than 70 mm Hg increased by a mean of 6 mm Hg (P < 0.0001). No complications occurred from this treatment, with the exception of electrolyte and chemistry abnormalities. At 6 months postinjury, the mortality rate was 28%, with 48% of patients achieving a favorable outcome by the dichotomized Glasgow Outcome Scale. CONCLUSION Hypertonic saline as a single osmotic agent decreased ICP while improving CPP and PbtO2 in patients with severe traumatic brain injury. Patients with higher baseline ICP and lower CPP levels responded to hypertonic saline more significantly.
-
8.
Cerebral perfusion in sepsis-associated delirium.
Pfister, D, Siegemund, M, Dell-Kuster, S, Smielewski, P, Rüegg, S, Strebel, SP, Marsch, SC, Pargger, H, Steiner, LA
Critical care (London, England). 2008;(3):R63
Abstract
INTRODUCTION The pathophysiology of sepsis-associated delirium is not completely understood and the data on cerebral perfusion in sepsis are conflicting. We tested the hypothesis that cerebral perfusion and selected serum markers of inflammation and delirium differ in septic patients with and without sepsis-associated delirium. METHODS We investigated 23 adult patients with sepsis, severe sepsis, or septic shock with an extracranial focus of infection and no history of intracranial pathology. Patients were investigated after stabilisation within 48 hours after admission to the intensive care unit. Sepsis-associated delirium was diagnosed using the confusion assessment method for the intensive care unit. Mean arterial pressure (MAP), blood flow velocity (FV) in the middle cerebral artery using transcranial Doppler, and cerebral tissue oxygenation using near-infrared spectroscopy were monitored for 1 hour. An index of cerebrovascular autoregulation was calculated from MAP and FV data. C-reactive protein (CRP), interleukin-6 (IL-6), S-100beta, and cortisol were measured during each data acquisition. RESULTS Data from 16 patients, of whom 12 had sepsis-associated delirium, were analysed. There were no significant correlations or associations between MAP, cerebral blood FV, or tissue oxygenation and sepsis-associated delirium. However, we found a significant association between sepsis-associated delirium and disturbed autoregulation (P = 0.015). IL-6 did not differ between patients with and without sepsis-associated delirium, but we found a significant association between elevated CRP (P = 0.008), S-100beta (P = 0.029), and cortisol (P = 0.011) and sepsis-associated delirium. Elevated CRP was significantly correlated with disturbed autoregulation (Spearman rho = 0.62, P = 0.010). CONCLUSION In this small group of patients, cerebral perfusion assessed with transcranial Doppler and near-infrared spectroscopy did not differ between patients with and without sepsis-associated delirium. However, the state of autoregulation differed between the two groups. This may be due to inflammation impeding cerebrovascular endothelial function. Further investigations defining the role of S-100beta and cortisol in the diagnosis of sepsis-associated delirium are warranted. TRIAL REGISTRATION ClinicalTrials.gov NCT00410111.
-
9.
Effects of electrical cervical spinal cord stimulation on cerebral blood perfusion, cerebrospinal fluid catecholamine levels, and oxidative stress in comatose patients.
Liu, JT, Tan, WC, Liao, WJ
Acta neurochirurgica. Supplement. 2008;:71-6
Abstract
OBJECTIVES Electrical spinal cord stimulation (SCS) is used to treat of chronic pain, obstructive arterial-related ischemia, and anginal pain. This study investigated cerebral blood perfusion, cerebrospinal fluid (CSF) catecholamine levels, and oxidative stress before and after cervical SCS in comatose patients. METHODS We evaluated cerebral blood perfusion, catecholamine (dopamine, norepinephrine, and epinephrine) levels, and oxidative stress in 20 comatose patients before and after SCS. After SCS for six months, cerebral blood perfusion (SPECT index, 2.293 +/- 0.255 vs. 2.779 +/- 0.209, p < 0.001), dopamine (49.0 +/- 12.1 vs. 198.9 +/- 62.6, p = 0.025), and norepinephrine (197.6 +/- 62.9 vs. 379.6 +/- 52.6, p = 0.021) but not epinephrine were significantly increased. Moreover, superoxide free radicals in whole blood were significantly decreased (210,079 +/- 47,763 vs. 109,212 +/- 20,086, p = 0.011) after SCS. Nine patients recovered from the consciousness within 71-287 days. CONCLUSIONS Increase of cerebral blood perfusion and catecholamines (dopamine and norepinephrine) in CSF after SCS was observed, whereas epinephrine level was unchanged. The superoxide free radicals were decreased after SCS. The results suggest that SCS increases cerebral blood perfusion, attenuates oxidative stress and increases biogenic amines in comatose patients.
-
10.
The effect of caffeine on dilated cerebral circulation and on diagnostic CO2 reactivity testing.
Blaha, M, Benes, V, Douville, CM, Newell, DW
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. 2007;(5):464-7
Abstract
Reduction of cerebral blood flow by caffeine has been shown in multiple studies. However, the effect of this substance on pathologically dilated cerebral vessels is not clearly defined. The aim of this study was to investigate the effect of caffeine on an already dilated cerebral circulation and specify if these vessels are still able to constrict as a consequence of caffeine stimulation. A second aim of this study was to compare results of cerebral vasomotor CO(2) reactivity testing with and without caffeine ingestion. Seventeen healthy adult volunteers had vasomotor reactivity tested before and thirty minutes after ingestion of 300 mg of caffeine. Each vasomotor reactivity test consisted of velocity measurements from both middle cerebral arteries using transcranial Doppler ultrasound during normocapnia, hypercapnia, and hypocapnia. Hemodynamic data and end-tidal CO(2) (etCO(2)) concentration were also recorded. The vasomotor reactivity (VMR) and CO(2) reactivity were calculated from a measured data pool. At a level of etCO(2)=40 mmHg the resting velocity in the middle cerebral artery (V(MCA)) dropped from 70.7+/-22.8 cm/sec to 60.7 +/- 15.4 cm/sec 30 minutes after caffeine stimulation (14.1% decrease, p<0.001). During hypercapnia of etCO(2)=50 mmHg there was also a significant decline of V(MCA) from 103.1+/-25.4 to 91.4+/-21.8 cm/sec (11.3%, p<0.001). There was not a statistically significant reduction of V(MCA) during hypocapnia. Calculated VMR and CO(2) reactivity before and after caffeine intake were not statistically significant. The presented data demonstrate a significant decrease in cerebral blood flow velocities after caffeine ingestion both in a normal cerebrovascular bed and under conditions of peripheral cerebrovascular vasodilatation. These findings support the important role of caffeine in regulation of CBF under different pathological conditions. Despite significant reactive vasodilatation in the brain microcirculation, caffeine is still able to act as a competitive antagonist of CO(2) on cerebral microvessels. The fact that caffeine may decrease CBF despite significant pathological vasodilatation offers the possibility of therapeutic manipulation in patients with traumatic vasoparalysis. For routine clinical testing of CO(2) reactivity it is not necessary to insist on pre-test dietary restrictions.