نتایج جستجو برای: ecg gated
تعداد نتایج: 53460 فیلتر نتایج به سال:
INTRODUCTION Cardiac motion is a common source of artifacts when imaging the chest with methods such as pulmonary perfusion MRI and pulmonary MR angiography (MRA). To minimize these artifacts, the MR sequence is often ECG-gated such that data are only acquired during a portion of the cardiac cycle when the heart is relatively quiescent; typically during diastole. However, this reduces scan effi...
Development of electrocardiographically (ECG) gated multisection computed tomography (CT) has had a significant, immediate impact in cardiovascular imaging. The capabilities of this new technique have become particularly important in the preoperative assessment of the cardiac surgery patient. Cardiac surgery in the 21st century has become increasingly complex because of an aging population need...
Background High fidelity 12-lead ECG is important for physiological monitoring during cardiovascular interventions. A dominant ECG R-wave is essential for synchronizing cardiac MRI. Obtaining the real ECG in MRI is challenging due to a superimposed Magneto-Hydro-Dynamic (MHD) voltage (VMHD) [1], & strong induced voltages from MRI switched gradients. Detecting acute ischemia by ST segment [2] is...
BACKGROUND To investigate the impact of high pitch cardiac CT vs. retrospective ECG gated CT on the quantification of calcified vessel stenoses, with assessment of the influence of tube voltage, reconstruction kernel and heart rate. METHODS A 4D cardiac movement phantom equipped with three different plaque phantoms (12.5%, 25% and 50% stenosis at different calcification levels), was scanned w...
BACKGROUND 4D cardiac computed tomography aims at reconstructing the beating heart from a series of 2D projections and the simultaneously acquired electrocardiogram. Each cardiac phase is reconstructed by exploiting the subset of projections acquired during this particular cardiac phase only. In these conditions, the Feldkamp, Davis and Kress method (FDK) generates large streak artifacts in the...
BACKGROUND In contrast to 201TlCl, 99mTc-sestamibi shows very slow myocardial clearance after its initial myocardial uptake. In the present study, myocardial washout of 99mTc-sestamibi was calculated in patients with non-ischemic chronic heart failure (CHF) and compared with biventricular parameters obtained from first-pass and ECG-gated myocardial perfusion SPECT data. METHODS AND RESULTS Af...
PURPOSE To evaluate the potential of prospective electrocardiography (ECG)- gated 64-slice multidetector computed tomography (MDCT) for evaluation of myocardial enhancement, infarct size, and stent patency after percutaneous coronary intervention (PCI) with stenting in patients with myocardial infarction. MATERIALS AND METHODS Seventeen patients who were admitted with acute myocardial infarct...
A noncontrast electrocardiography (ECG)-gated, fast-spin-echo magnetic resonance imaging was applied to noninvasively define perfusion impairments in pulmonary embolic and airway obstruction dog models. Two-phase ECG-gated lung images of the minimal lung signal intensity during systole and maximal signal intensity during diastole were acquired by using optimized R-wave triggering delay times in...
BACKGROUND We aimed to study whether pulmonary arterial distensibility (PAD) correlates with hemodynamic parameters in chronic thromboembolic pulmonary hypertension (CTEPH) using electrocardiogram (ECG)-gated 320-slice multidetector computed tomography (MDCT). METHODS AND FINDINGS ECG-gated 320-slice MDCT and right heart catheterization (RHC) was performed in 53 subjects (60.6±11.4 years old;...
Background ECG-gated cardiac MRI is the gold standard for volumetric evaluation of patients, and clinically, ejection fraction is used as a surrogate for function. We hypothesized that the use of arrhythmia rejection in the presence of ectopic beats compromises the accuracy of hemodynamic measurements. Real-time MRI, coupled with ECG telemetry and semi-automated LV endocardial segmentation, can...
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