Search results for "ROV"
showing 10 items of 5770 documents
FAIR and dynamic susceptibility contrast-enhanced perfusion imaging in healthy subjects and stroke patients.
2002
Purpose To compare dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) and the flow-sensitive alternating inversion recovery (FAIR) technique for measuring brain perfusion. Materials and Methods We investigated 12 patients with acute stroke, and 10 healthy volunteers with FAIR and DSC maps of regional cerebral blood volume (rCBV), mean transit time (MTT), and regional cerebral blood flow (rCBF). Results In volunteers good gray/white-matter contrast was observed in FAIR, rCBF, and rCBV maps. Regions with high signal intensities in FAIR matched well with high values of rCBV and rCBF. In ischemic stroke patients a high correlation (r = 0.78) of the ipsi- to contralate…
Effect of intraarterial papaverine or nimodipine on vessel diameter in patients with cerebral vasospasm after subarachnoid hemorrhage.
2012
Papaverine (P) and nimodipine (N) are the most widely used vasodilators when angiographic and symptomatic vasospasm is present after subarachnoid aneurysmatic hemorrhage (SAH). Their effect is only short-lived and no direct comparisons have been undertaken to evaluate the action of both substances directly. We retrospectively assessed the effect of either P or N on angiographic diameter reduction and capillary blood flow.Fifteen SAH patients with secured aneurysms and cerebral vasospasm received intraarterial P, fifteen similar patients received N. As the primary endpoint, pre- and post-infusion arterial diameters and capillary blood flow were rated retrospectively on angiographies and comp…
Exogenous and endogenous provocation of psoriasis. A contribution to the Koebner phenomenon.
1974
Previous literature reports as well as own investigations concerning exogenously and endogenously induced Koebner-reactions in psoriatics are presented. The time interval between irritation and the Koebner-reaction is emphasized. It is proposed, that the intensity of the psoriatic reaction is mediated by circulating DHEA-deficiency. Hypothetical models are presented which allow to explain the different developmental rates of psoriatic lesions in relation to the type of irritation, the area affected and the subsequent proliferative responses.
Immediate temporary restoration of single-tooth implants : prospective clinical study
2010
Purpose: The goal of this study is to assess the survival, marginal bone loss and complications around sing le-tooth implants on which immediate provisionalization was carried out. Patients and Methods: 78 implant were placed in 57 patients: 56 after extraction and 22 in healed sockets. Immediately after surgery provisional crowns were delivered without contacts in both centric and excursive jaw movements. The final crowns were inserted between 3 to 6 months later. During the study there were 3 x-rays taken per patient. The marginal bone loss was measured and complications were recorded. The statistical analys is of the data was carried out with the STATA 10® software. Results: The mean dur…
Serial Measurement of Static and Dynamic Cerebrovascular Autoregulation After Brain Injury
2011
In patients with neuronal injury, the knowledge of the status of cerebrovascular autoregulation can help to optimize the management of the cerebral perfusion pressure. This study characterizes dynamic and static cerebrovascular autoregulation during the first 7 days after severe traumatic brain injury or intracranial hemorrhage.After approval from the IRB, 16 patients were studied. Cerebral blood flow velocity (CBFV) was measured daily for the assessment of dynamic (10 patients) and static (16 patients) cerebrovascular autoregulation in both the middle cerebral arteries using the transcranial Doppler sonography. Dynamic cerebrovascular autoregulation (dAR) was measured using the cuff-deflat…
Transcranial Doppler diagnosis of cerebral vasospasm following subarachnoid haemorrhage: correlation and analysis of results in relation to the age o…
1994
A retrospective analysis was undertaken to determine whether cerebral vasospasm following subarachnoid haemorrhage (SAH) correlates with the age of patients. For at least 3 weeks after bleeding 80 subjects underwent very close follow-up with clinical examination and transcranial Doppler records of the blood velocities within the basal cerebral arteries. Firstly a correlation between measured maximal mean blood flow velocities and age was made. Secondly, according to their age and the maximum of recorded mean velocities (v), the patients were divided into groups as follows: age 55 years or less, age more than 55 years; and maximum velocity v190 cm/s, 90 cm/sv2120 cm/s, 120 cm/sv3160 cm/s, v4…
Exploring metrics for the characterization of the cerebral autoregulation during head-up tilt and propofol general anesthesia
2022
Techniques grounded on the simultaneous utilization of Tiecks' second order differential equations and spontaneous variability of mean arterial pressure (MAP) and mean cerebral blood flow velocity (MCBFV), recorded from middle cerebral arteries through a transcranial Doppler device, provide a characterization of cerebral autoregulation (CA) via the autoregulation index (ARI). These methods exploit two metrics for comparing the measured MCBFV series with the version predicted by Tiecks' model: normalized mean square prediction error (NMSPE) and normalized correlation rho. The aim of this study is to assess the two metrics for ARI computation in 13 healthy subjects (age: 27 & PLUSMN; 8 yr…
Control for carbon dioxide-related changes in flow velocity by transcranial Doppler monitoring.
1994
Transcranial Doppler ultrasonography can monitor changes in intracranial blood flow velocity over time in a variety of experimental and clinical settings with excellent temporal resolution. Alterations in arterial carbon dioxide pressure exert a profound influence on blood flow velocity. Such changes exhibit important individual fluctuation depending on respiratory status. This limits the ability of transcranial Doppler to accurately study subtle changes in blood flow velocity, independent of the respiratory state of the subject. Suggested here is a method to control for the respiration artifact on blood flow velocity. The middle cerebral artery of 7 healthy male volunteers was studied with…
Anatomical correlates of visual and tactile extinction in humans: a clinical CT scan study.
1994
The anatomical correlates of tactile and visual extinction with double simultaneous stimulation were investigated in a series of 159 patients with right brain damage caused by stroke. Forty six patients showed extinction (22 tactile, 14 visual, 10 tactile and visual). Over 50% of the patients with extinction had deep lesions, which were found in about 25% of the patients with visuospatial neglect not associated with extinction. In the patients with extinction and cortico-subcortical damage the paraventricular occipital white matter and the dorsolateral frontal cortex were most often involved. By contrast, when neglect was also present, the lesions clustered in the inferior parietal lobule. …
Want a tip? Service performance as a function of emotion regulation and extraversion.
2011
Surface acting and deep acting with customers are strategies for service performance, but evidence for their effectiveness is limited and mixed. We propose that deep acting is an effective strategy for most employees, whereas surface acting's effect on performance effectiveness depends on employee extraversion. In Study 1, restaurant servers who tended to use deep acting exceeded their customers' expectations and had greater financial gains (i.e., tips) regardless of extraversion, whereas surface acting improved tips only for extraverts, not for introverts. In Study 2, a call center simulation, deep acting improved emotional performance and increased the likelihood of extrarole service beha…