The fast Fourier transform (FFT), which is employed by all commercially available ultrasonic systems, provides a time-frequency representation of Doppler ultrasonic signals obtained from blood flow. The FFT assumes that the signal is stationary within the analysis window. However, the presence of short duration embolic signals invalidates this assumption. For optimal detection of embolic signal...

Dates to which data relate Effectiveness data in the principal pilot study corresponded to patients examined between April and September 1997. Effectiveness data in the validation pilot study corresponded to patients examined between May and October 1997. Some effectiveness data were based on assumptions from two studies published in 1995 and 1997. Resource consumption data were based on a surv...

The main pulmonary trunk was banded in four fetal sheep at 63--69 days of gestation. The fetuses were killed after they had developed progressive pulmonary stenosis at 98, 123, 134 and 135 days of gestation. The right lung of each animal was perfused with glutaraldehyde and serial sections followed microscopically. The medial width/external diameter ratios for fifth generation resistance vessel...

Stenosis in the internal carotid arteries is a serious cardiovascular condition. It well-reported that low and oscillatory wall shear stress enhances risk of stenosis progression. However, effects increased heart rates highly stenosed are not well explored. A detailed understanding flow features distribution at different may help clinicians to prescribe better exercise schedules for patients. I...

In this study, Doppler signals recorded from internal carotid artery of 45 subjects were processed by PC-computer using classical (fast Fourier transform) and model-based (autoregressive, moving average, autoregressive moving average (ARMA) methods) methods. Power spectral density estimates of internal carotid arterial Doppler signals were obtained using these spectral analysis methods. The var...

Mass transport may play a significant role in the development of atherosclerosis, a progressive disease of the artery wall. In this work, advection-dominated transport of blood-borne components such as oxygen and ATP is considered in two arterial models with mild (56% area reduction) stenoses, representative of the early stages of disease development. Flow and mass transport patterns in a symme...

Background and Purpose—Patients with a carotid artery stenosis, including those with an asymptomatic or moderate stenosis, have a considerable risk of ischemic stroke. Identification of risk factors for cerebrovascular disease in these patients may improve risk profiling and guide new treatment strategies. We cross-sectionally investigated whether carotid stiffness is associated with previous i...

Methods and Materials In 200 out of 660 patients undergoing carotid endarterectomy (CEA) for a high-degree ICA stenosis, pre-operatively a bilateral selective carotid and intracerebral angiography was performed. The degree of the ipsilateral and contralateral stenosis was digitally assessed by using computer software according to the CC-Index. Intraoperatively, the pressure ratio over the steno...

BACKGROUND AND PURPOSE Patients with a carotid artery stenosis, including those with an asymptomatic or moderate stenosis, have a considerable risk of ischemic stroke. Identification of risk factors for cerebrovascular disease in these patients may improve risk profiling and guide new treatment strategies. We cross-sectionally investigated whether carotid stiffness is associated with previous i...