Annet Waaijer

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BACKGROUND AND PURPOSE Different definitions have been proposed to define the ischemic penumbra from perfusion-CT (PCT) data, based on parameters and thresholds tested only in small pilot studies. The purpose of this study was to perform a systematic evaluation of all PCT parameters (cerebral blood flow, volume [CBV], mean transit time [MTT], time-to-peak)(More)
PURPOSE To prospectively assess the effects of lower tube voltage and various effective tube currents on image quality for computed tomographic (CT) angiography of the circle of Willis. MATERIALS AND METHODS Institutional review board approval was obtained. Patients or family provided written informed consent. Signal-to-noise ratios (SNRs) were determined(More)
BACKGROUND CT perfusion (CTP) is an important diagnostic tool for the imaging of cerebral hemodynamics. To obtain quantitative values of cerebral blood volume (CBV), blood flow (CBF), and mean transit time (MTT), measurement of the arterial input function (AIF) is required. To correct for partial volume effects (PVEs), it is common to normalize the AIF with(More)
BACKGROUND The International Carotid Stenting Study (ICSS) of stenting and endarterectomy for symptomatic carotid stenosis found a higher incidence of stroke within 30 days of stenting compared with endarterectomy. We aimed to compare the rate of ischaemic brain injury detectable on MRI between the two groups. METHODS Patients with recently symptomatic(More)
PURPOSE To prospectively evaluate changes in brain perfusion computed tomographic (CT) parameters after revascularization of unilateral symptomatic carotid artery stenosis and to determine whether pretreatment perfusion CT parameters can be used to predict changes in cerebral hemodynamics after treatment. MATERIALS AND METHODS This study was medical(More)
BACKGROUND AND PURPOSE Waiting lists for radiotherapy have become longer over the past years. Apart from the psychological distress for the patient we are concerned about tumour growth during this waiting time, which may worsen prognosis. The purpose of this pilot study was to investigate tumour growth in the waiting time and to obtain an indication of its(More)
PURPOSE CT angiography (CTA) scans are the current standard for vascular analysis of patients with cerebrovascular diseases, such as acute stroke and subarachnoid hemorrhage. An additional CT perfusion (CTP) scan is acquired of these patients to assess the perfusion of the cerebral tissue. The aim of this study is to extend the diagnostic yield of the CTP(More)
BACKGROUND AND PURPOSE To establish intraobserver and interobserver variability for regional measurement of CT brain perfusion (CTP) and to determine whether reproducibility can be improved by calculating perfusion ratios. MATERIALS AND METHODS CTP images were acquired in 20 patients with unilateral symptomatic carotid artery stenosis (CAS). We manually(More)
To assess the optimal method for grading carotid artery stenosis with computed tomographic angiography (CTA), we compared visual estimation to caliper measurements, and determined inter-observer variability and agreement relative to digital subtraction angiography (DSA). We included 46 patients with symptomatic carotid stenosis for whom CTA and DSA of 55(More)
PURPOSE To assess the presence of anterior and posterior collateral pathways in the circle of Willis in patients with symptomatic carotid artery stenosis (SCAS) and to compare this to patients without carotid artery stenosis. MATERIALS AND METHODS Multislice CT angiography was performed in 91 patients and 91 control subjects. Using consensus reading, 2(More)