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Background. Light-to-moderate alcohol consumption has been associated with a lower risk of cardiovascular disease. The protective effect of alcohol could involve arterial properties as arterial stiffness and distensibility. Methods. The relationship between alcohol and arterial stiffness was studied within the framework of the Rotterdam Study, a population-based study in individuals aged 55 and older. The present study included 3178 participants in the third examination phase. Arterial stiffness was measured by two different methods, i.e., the carotid femoral pulse wave velocity and the DC of the common carotid artery. Categories of alcohol consumption were defined as follows: [less than or equal to] 3 glasses of alcohol per week, 4-10 glasses per week, 11-20 glasses per week, and [greater than or equal to] 21 glasses per week. Linear regression analysis was used to investigate the association between alcohol consumption and measures of arterial stiffness. Results. In multivariate-adjusted models, women drinking 4--10, 11-20, and [greater than or equal to] 21 glasses of alcoholic beverage per week had a -0.07 (0.22 to -0.38), -0.18 (0.12 to -0.49), and 0.12 (0.19 to -0.43) m/s difference in mean pulse wave velocity compared to those drinking 0-3 glasses per week (reference group). Corresponding differences in the carotid DC were 0.68 (1.21 to 0.15), 0.28 (0.82 to -0.25), and 0.36 (0.91 to -0.18) [10.sup.-3]/kPa. In men, the estimates were not statistically significant, although a similar trend was observed. Conclusions. Moderate alcohol consumption is associated with lower arterial stiffness in women independently of cardiovascular risk factors and atherosclerosis.

To assess locally deviating structural and mechanical properties of arterial walls, the spatial variance in end-diastolic intima media thickness (IMT) and the change in IMT during the cardiac cycle ([DELTA]IMT) were determined along a short segment of the common carotid artery (15.86 mm), at 16 positions simultaneously. Intrasubject spatial inhomogeneities along the artery were revealed by a spatial variance significantly larger than the temporal variance over several beats. If differences between positions were confirmed, the extent of the inhomogeneity was obtained by comparison of IMT and [DELTA]IMT at each position with their spatial medians [+ or -] the least-significant difference. Because no intersubject comparisons were necessary, a single session of several measurements was sufficient to assess inhomogeneities in the arterial wall properties of a subject, making the method independent of biological variability between subjects. The method was evaluated on 47 presumed healthy subjects (age range 21-75 yr). In 22 subjects, spatial inhomogeneities in [DELTA]IMT occurred (P < 0.05). In young subjects, [DELTA]IMT was locally decreased, i.e., in systole inhomogeneities were less compressed than their surrounding tissue. In older subjects, [DELTA]IMT was locally increased, i.e., the inhomogeneity was locally more compressed than its surrounding wall tissue. ultrasound; radial strain; compressibility; arterial stiffness

All Doppler systems, whether conventional Doppler domain or radio frequency (RF) processing is employed, relate the temporal frequency characteristics of the signal at a certain point in depth as function of time to the spatial frequency characteristics of the received signal as function of depth. The mean frequency of the latter may change as a result of depth-dependent attenuation, nonlinear scattering mechanisms, as in harmonic imaging of ultrasound contrast agents, or RF signal demodulation. For all these cases, the relationship between spatial and temporal mean frequency and target velocity is still governed by the familiar Doppler expression if the signal modifications have been properly accounted for. A major drawback of RF signal processing to extract the target velocity is the large number of data points to consider. The computational complexity increases further for harmonic imaging. It is shown conceptually, and demonstrated by signal simulations, that prior to velocity estimation RF demodulation followed by decimation 1) does not affect the Doppler equation, 2) enhances the information content of the samples, 3) reduces the computational load by a factor of four and for harmonic signals by a higher factor, and 4) while demodulation does not have to be actually performed, but can be accounted for by a scaling factor in the cross-correlation function. It is concluded that decimation hardly affects the precision of the velocity estimate if possible frequency aliasing is maintained within bounds, suggesting that the decimation factor is not critical. Index Terms - Baseband estimation, computational load, Doppler equation invariance, RF domain processing, second-harmonic ultrasound signals, virtual RF demodulation and de-cimation.

A novel technique to assess aortic distensibility and compliance in anesthetized and awake rats has been developed. It was based on a technique developed for humans but unlike the original, this technique uses radio frequency signal processing instead of Doppler signal processing. It involves end-diastolic aortic diameter and aortic diameter changes during the cardiac cycle as parameters.