Ultrasound Intima-media Thickness Measurements Research Articles

Hormonsubstitution im Klimakterium und zerebrovaskuläre Erkrankungen

Epidemiologic and animal studies have provided evidence that hormone replacement therapy can reduce the risk of stroke. Doppler ultrasound measurements of blood flow show a positive effect of estrogens on the cardiovascular system, which is only slightly modified by progestins. Ultrasound measurements of intima-media thickness showed a positive influence of long-term hormone replacement therapy on the cerebral vasculature. The intima-media thickness, a marker of complex atherosclerosis decreases with hormone replacement therapy. The number of atherosclerotic plaques in extracranial cerebral vessels is significantly lower in patients receiving hormone replacement than in controls. One study suggested that estrogen replacement can lead to regression of atherosclerotic plaques. Hormone replacement therapy may reduce the risk for developing and progression of cerebrovascular atherosclerosis. In patients with a history of stroke the possible benefits of hormone replacement have to be weighed against risks, particularly in patients with other risk factors. We review our results and the literature.

How can the variability in ultrasound measurement of intima-media thickness be reduced? Studies of interobserver variability in carotid and femoral arteries.

A critical component in scientific studies of most biological variables is the variation or error in measurements which leads to non-identical results of repeated measurements from the same subject. The aim of this study was to investigate whether the interobserver error (s) in measurement of intima-media thickness (IMT) in carotid and femoral arteries could be decreased if the mean value obtained using two ultrasound images from each of the right and left arteries was used in the analyses instead of the mean value obtained using images from only the right artery. In addition, we wished to evaluate two different reading procedures, one based on manual tracing of echo interfaces and the other on automated edge detection. In a methodological study, 50 subjects were examined with ultrasound twice in the same day by two independent laboratory technologists. The ultrasound images were analysed in two ways: using a computerized manual tracing analysing system and an automated analysing system. When both right and left carotid arteries were examined (manual reading), the interobserver error was smaller than that determined for the examination of only the right artery, for IMTmean in both the common carotid artery (P = 0.06) and the carotid artery bulb (P < 0.05). The interobserver error was also significantly smaller for double-sided vs. one-sided examination with automated reading of IMTmean in the common carotid artery (P < 0.01) and in the carotid artery bulb (P < 0.01). The coefficient of variation (CV) for measurement in the common carotid artery decreased from 8.6% (one-sided, manual reading) to 5.3% (double-sided, automated reading). The interobserver error in measurement of IMT in the common femoral artery did not improve by examination of both right and left arteries. The results from this study show that the interobserver errors in measurement of IMT can be decreased by using ultrasound images from both the right and the left carotid arteries, and that the use of an automated analysing system greatly simplifies the reading of ultrasound images with sustained low variability.

Variance components analysis of carotid and femoral intima-media thickness measurements

B-mode ultrasound intima-media thickness (IMT) measurements of carotid and femoral arterial walls are used in atherosclerosis studies. In this study, the components contributing to IMT measurement variability in males with coronary artery disease were investigated by means of repeated B-mode ultrasound scans and repeated off-line video image analyses. For statistical analysis, a mixed-model analysis of variance was used. From sonographer data, it was shown that human subjects and their arterial wall segments contributed 75% of the total IMT measurement variability in this population. Inter-sonographer variance contributed 25%. The intra-sonographer variance was negligible (<1%). In off-line image analysis, variance components due to subjects and segments, inter-analyst variance, and residual fluctuation were 88%, <1% and 11%, respectively. Intra-analyst variance was negligible (<1%). The major source of B-mode ultrasound IMT measurement variability finds its origin in subjects and their arterial walls. Although sonographers proved a lesser source of variability, in comparative studies they should enter a study well trained and should be randomly assigned to subjects. Follow-up examinations should preferably be done by the same sonographer. Off-line image analysis contributed little to IMT measurement variability.

3.P.346 How can the variability in ultrasound measurement of intima-media thickness be reduced?

3.P.346 How can the variability in ultrasound measurement of intima-media thickness be reduced?

Atherosclerotic changes in the carotid artery bulb as measured by B-mode ultrasound are associated with the extent of coronary atherosclerosis.

Ultrasound is increasingly used to measure atherosclerotic development in carotid and femoral arteries. The aim of this study was to investigate the relationship between coronary atherosclerosis as measured by quantitative angiography and peripheral atherosclerosis as measured by ultrasound in three different arterial regions. Patients (n = 32) with at least two coronary segments with visible signs of atherosclerosis as defined in a computer-assisted analysis of coronary angiograms were also examined with B-mode ultrasound. The extent of coronary atherosclerosis was expressed as the average diameter stenosis of coronary segments, and peripheral atherosclerosis was defined as intima-media thickness (IMT) and plaque occurrence in the common carotid artery, the carotid bulb, and the common femoral artery. The results showed a significant correlation between the ultrasound measurement of IMT of the carotid bulb and diameter stenosis of the included coronary segments (r = .68, P = .01) and of carotid plaques and diameter stenosis (P < .001). The correlation between common carotid IMT and diameter stenosis of included coronary segments was not statistically significant (r = .31, NS). There were no significant relationships between common femoral IMT or femoral plaques and diameter stenosis of included coronary segments. Although this study is small, it points to a very important aspect of ultrasound measurements of atherosclerosis: measurements performed in the common carotid artery or the femoral artery may not relate to coronary atherosclerosis in the same way as measurements performed in the carotid bulb. The findings underline the importance of measuring IMT not only in the common carotid artery but also in the carotid bulb and present data separately. These results have to be confirmed in a larger-scale study.

High-resolution B-mode ultrasound measurement of intima-media thickness in carotid and femoral arteries shows no increased prevalence of premature atherosclerosis in heterozygotes for homocystinuria

High-resolution B-mode ultrasound measurement of intima-media thickness in carotid and femoral arteries shows no increased prevalence of premature atherosclerosis in heterozygotes for homocystinuria

Ultrasound-determined intima-media thickness and atherosclerosis. Direct and indirect validation.

To evaluate ultrasonographically determined intima-media thickness as a measure of early atherosclerosis, three studies were performed. Ultrasound measurements of intima-media thickness in the carotid artery were directly validated by comparing the same thickness measured by light microscopy. The values were closely correlated (r = .82, P < .001). Intima-media thickness determined by light microscopy was consistently smaller than that determined by ultrasound, probably due to shrinkage during histological preparation. As an indirect validation, mean intima-media thickness was calculated in three large groups of patients with no plaque (n = 224), one plaque (n = 105), and one circumferential or two or more plaques (n = 54) in the carotid bifurcation. Intima-media thickness increased significantly with increasing plaque score, indicating that diffuse intima-media thickening is more pronounced with more severe atherosclerosis. The intima-media thickness also increased with increasing multifactorial cardiovascular risk, reflecting a positive relation between signs of early atherosclerosis and the burden of known risk factors for the disease. Our studies support earlier findings that have found that ultrasonographically determined intima-media thickness is a valid way to study early atherosclerosis.

Arterial wall thickness in familial hypercholesterolemia. Ultrasound measurement of intima-media thickness in the common carotid artery.

B-mode ultrasound was used to noninvasively determine wall thickness and lumen diameter in the common carotid artery in patients with familial hypercholesterolemia (n = 53) and in a control group (n = 53). The controls were matched for sex, age, height, and weight, and all had a serum cholesterol level below 6.5 mmol/l. The study was performed to evaluate whether the patients had a thicker arterial wall compared with that of the control group. Wall thickness was determined as the combined intima-media thickness of the far wall and is presented as the mean and maximum thickness of a 10-mm-long section of the common carotid artery. The difference between the groups was 0.13 mm in mean wall thickness (p less than 0.001; 95% confidence interval, 0.07-0.18 mm) and 0.20 mm in maximum wall thickness (p less than 0.001; 95% confidence interval, 0.09-0.23 mm). Fifty of the subjects were examined twice to estimate the interobserver variability. The coefficients of variation for mean and maximum wall thickness were 10.2% and 8.9%, respectively. The two study groups were well matched and differed only in lipid levels. Thus, there is reason to believe that the difference in wall thickness can be explained by the background of familial hypercholesterolemia and the increased cholesterol levels.

Progression and regression of carotid atherosclerosis in clinical trials.

Progression and regression of carotid atherosclerosis in clinical trials 1524-4636 Copyright © 1991 American Heart Association. All rights reserved. Print ISSN: 1079-5642. Online ISSN: 7272 Greenville Avenue, Dallas, TX 72514 Arteriosclerosis, Thrombosis, and Vascular Biology is published by the American Heart Association. 1991, 11:443-451 Arterioscler Thromb Vasc Biol http://atvb.ahajournals.org/content/11/2/443.citation located on the World Wide Web at: The online version of this article, along with updated information and services, is