View clinical trials related to Cerebral Blood Flow.
Filter by:The purpose of this study is to explore the changes of fasting and postprandial cerebral blood flow in patients with type 2 diabetes mellitus. Some studies have proved that non-fasting blood glucose concentration is an independent predictor of ischemic stroke and lacunar infarction. At present, there are differences in cerebral blood flow velocity between diabetic patients and healthy controls. Therefore, it is of certain significance to explore the changes of fasting and postprandial cerebral blood flow in patients with type 2 diabetes mellitus.
The purpose of this study is to assess cerebral blood flow velocity (CBFV) following regional anesthesia for shoulder surgery. The results of this study will help to further understand the physiologic effect of the interscalene nerve block on cerebral blood flow.
Cerebral blood flow measurement, which is applied to patients with cerebrovascular-related diseases, provides useful information about hemodynamic status. There was a method using Doppler ultrasound and phase contrast (PC) MRI, but it was not widely used in clinical practice due to limitations in reproducibility between examiners, complexity of procedure, and time-intensive protocol. We intend to measure cerebral blood flow through the signal-intensity gradient (SIG) technique using Time-of-Flight (TOF) of brain magnetic resonance imaging, which can compensate for the shortcomings of the existing research methods. In addition, by analyzing the correlation with the previous methods, Doppler ultrasound and PC MRI, we will evaluate the effectiveness of our new method.
Iron deficiency is the most prevalent nutritional deficiency worldwide with one in four estimated to be affected by iron deficiency anaemia. Women of reproductive age are at greatest risk for iron deficiency and anaemia due to iron losses during menstruation and childbirth as well as the increased need for iron throughout pregnancy. However, iron deficiency without anaemia is at least twice as common as iron deficiency anaemia with females aged 11-49 at the biggest risk of all. Despite this, it is commonly left undiagnosed. Those who are iron deficient non-anaemic can still suffer from the same common consequences of iron deficiency anaemia; these include unexplained fatigue, mood changes and decreased cognitive performance. It is postulated that for any cognitive and behavioural change to occur, a complementary change in neural functioning is required. A recent cross-sectional study has identified increases in cognitive demand to produce decrements in measures of cognitive performance and increases in brain activity and metabolic measures; the magnitude of such are evidenced to be directly related to iron status. However, such measures do not provide an estimate of overall oxygen consumption that is specific to the brain in order to be able to associate changes in cognitive performance and energy expenditure specifically to the brain itself. The current study aims to investigate the parallel effects of iron supplementation on cerebral haemodynamics and energy metabolism to determine the ability of iron to modulate whole body energy metabolism and utilisation of metabolic substrates at rest and during cognitive demand in a sample of non-anaemic iron deficient and iron sufficient women of reproductive age.
Little is known about how implementation of pneumoperitoneum contributes to cerebral blood flow in pediatrics. We investigated this question in patients undergoing laparoscopic surgery, hypothesizing that cardiorespiratory changes during this procedure would reduce cerebral perfusion.
Cognitive performance is negatively related to an impaired glucose metabolism, possibly due to impairments in brain vascular function. Supported by the statement from the American Heart and Stroke Association that a healthy lifestyle is one of the most effective strategies to protect against cognitive decline, the investigators now hypothesise that healthy lifestyle intervention-induced changes in glucose metabolism cause beneficial effects on brain vascular function thereby improving cognitive performance. The primary objective of this intervention study is thus to evaluate in sedentary older men and women the effect of a 16-week aerobic-based exercise program on cerebral blood flow, as quantified by the non-invasive gold standard magnetic resonance imaging (MRI) perfusion method Arterial Spin Labeling (ASL). Cerebral blood flow is a robust and sensitive physiological marker of brain vascular function. Secondary objectives are to examine effects on glucose metabolism using the homeostatic model assessment for insulin resistance (HOMA-ir) and cognitive performance as assessed with a neurophysiological test battery.
To investigate the hemodynamic effects of CGRP after glibenclamide administration.
Impaired brain vascular function precedes the development of reduced cognitive performance, while brain insulin-resistance is also associated with cognitive decline. The Mediterranean diet, which is rich in nuts, may protect against the development of impaired cognitive performance. The hypothesis is that long-term mixed nut consumption increases brain insulin-sensitivity thereby improving brain vascular function and cognitive performance. The primary objective is to evaluate in elderly men and women the effect of 16-week mixed nut consumption on cerebral blood flow, as quantified by the non-invasive gold standard magnetic resonance imaging (MRI)-perfusion method Arterial Spin Labelling (ASL). Cerebral blood flow is a robust and sensitive physiological marker of brain vascular function. Secondary objectives are to investigate effects on the cerebral blood flow response to intranasal insulin delivery - a marker of insulin-sensitivity in the human brain - as quantified by ASL, and cognitive functioning as assessed with a neuropsychological test battery.
We planned to evaluate cerebral blood flow and its association with age, blood pressure, and end tidal carbon dioxide in small pediatric using transfontanelle ultrasound during general anesthesia.
When astronauts return from space flight, they manifest a set of symptoms, the most striking of which is orthostatic intolerance, that is, the inability to stay upright. This orthostatic intolerance is related to cardiovascular adaptation and disappears in a few days, but the prospect of long-term space travel makes this maladaptation a major concern of space agencies, at a time when there is serious consideration to make " land "a ship on Mars. Previous studies suggest that brain vessel adaptation may contribute to spatial post-flight orthostatic intolerance. The question remains controversial because not all studies are consistent. These studies are all based on the measurement of blood flow in a single artery of the brain (the average cerebral, see cerebral circulation diagram) easily accessible with a Doppler ultrasound machine. Our team has good reason to believe that the adaptation of the cerebral vessels is not carried out in the same way in all the arteries of the brain and that in particular the arteries that irrigate the posterior and inferior parts of the brain are a major determinant. from cerebrovascular adaptation to orthostatism and that orthostatic intolerance is more specifically related to a decrease in blood flow in these arteries. On the other hand our team has shown that the external carotid artery plays, under certain conditions, a buffer role of the sudden variations of perfusion pressure of the brain. During the weightless phase of parabolic flight, part of the blood from the legs and abdomen "rises" to the thorax and this transfer of fluid induces changes in blood pressure and cardiac output that affect the cerebral circulation. From a cardiovascular point of view, it is the same thing for a seated subject to lie down, but the parabolic flight offers the unique possibility of achieving this transfer in a fraction of a second and thus allowing to study the immediate response of the cerebral circulation. . Investigators goal is therefore to quantify the changes in blood flow in the posterior and anterior territories of the brain (transcranial ultrasound) as well as in the internal carotid and vertebral (Doppler ultrasound) during changes in blood pressure and cardiac output induced by transfers. liquid resources associated with the transition to weightlessness. The oxidative stress generated by weightlessness has been identified as a determining factor in cerebrovascular deconditioning associated with orthostatic intolerance. In order to quantify the biochemical markers of this stress, a venous sample will be taken before and just after the parabolic flight.