The new automated analyzing system will not only greatly increase the speed of measurements but also reduce the variability between readers. It should also reduce the variability between different laboratories if the same analyzing program is used. Furthermore, the new system will probably prevent the problem with drift in measurements over time.

A B-mode [two-dimensional (2D)] image from the carotid artery may be described as containing seven echo zones. The aim of the present work is to discuss how lumen diameter and wall thickness can be measured from these zones, and to review some of the basic principles of ultrasound physics and imaging. Simple experiments were performed to identify the echoes defining intima-lumen interfaces. The results showed that: (1) The intima-media thickness of the near wall cannot be measured in a valid way. (2) The lumen diameter of a blood vessel is defined by the distance from the leading edge of the intima-lumen interface of the near wall (echo zone 3) to the leading edge of the lumen-intima interface of the fall wall (echo zone 5). (3) Previously published studies have validated the intima-media complex of the far wall as the distance from the leading edge of the lumen-intima interface of the far wall to the leading edge of the media-adventitia interface of the far wall (echo zone 7). We suggest that if measurements on the near wall are performed, measurements from the far wall should also be presented separately, and if lumen diameter is measured, that this measurement is carried out according to the leading edge principle. We describe a computerized analysing system for the measurement of wall thickness and plaque area on the carotid and femoral arteries. The system is based on a low-cost PC and a frame grabber board and calculates minimum, maximum and mean values of lumen diameter and wall thickness from a section of the artery.

The present prospective multicenter study indicates that the prefabrication, on the basis of models derived from three-dimensional oral implant planning software, of both surgical templates for flapless surgery and dental prostheses for immediate loading is a very reliable treatment option. It is evident that the same approach could be used for staged surgery and in partial edentulism.

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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.

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/1. 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<0.001; 95% confidence interval, 0.07-0.18 mm) and 0.20 mm in maximum wall thickness (p<0.001; 95% confidence interval, 0.09-023 mm). Fifty of the subjects were examined twice to estimate the interobserver variability. The coefficients of variation for mean and maximum wall thickness were 102% 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. {Arteriosclerosis and Thrombosis 1992; 12:70-77)

OBJECTIVE: To investigate the extent of carotid artery atherosclerosis in obese subjects and to examine the possible effects of weight loss on atherosclerotic development. DESIGN: Controlled 4 y intervention study. SUBJECTS: 20 obese patients treated with weight-reducing gastroplasty, 19 obese patients treated with dietary recommendations and 35 lean subjects. MEASUREMENTS: Body weight, blood pressure, blood lipids, glucose and insulin were measured. A B-mode ultrasound was recorded to determine the intima-media thickness (IMT) and lumen diameter (LD) of the carotid artery. Study groups were investigated at baseline and re-examined after 3 to 4 y of follow-up. RESULTS: At baseline, obese patients had higher blood pressure, serum total cholesterol, triglycerides, glucose and insulin compared with lean subjects; they also had a larger IMT in the carotid artery bulb (P`0.05) and a larger LD in the common carotid artery (P`0.01). After 4 y of follow-up, obese patients treated with surgery displayed a mean weight loss of 22 kg (19%), while the average weight in the obese control group remained unchanged (P`0.001). The weight loss group showed improvements in blood pressure, HDL-cholesterol, triglycerides and insulin compared with the obese control group (P`0.05). The progression rate of carotid bulb IMT in the weight loss group was similar to that observed in the lean control group (0.024 vs 0.025 mmay, n.s.), whereas the IMT progression rate was almost three times higher in the obese control group (0.068 mmay, P`0.05 compared with lean controls). CONCLUSION: Obese people have an unfavourable risk factor pro®le and signs of premature carotid artery atherosclerosis. Weight loss is followed by an improvement in several risk factors and may reduce the progression rate of atherosclerotic changes in the carotid artery bulb.

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.