Influence of vascular risk factors for atherosclerotic carotid artery plaque progression

Decreased GFR and its joint association with type 2 diabetes and hypertension with prevalence and severity of carotid plaque in a community population in China

BACKGROUND

Type 2 diabetes (T2DM), hypertension and kidney dysfunction are known risk factors for cardiovascular disease, but their combined effect on carotid plaque remains uncertain. This study aims to assess the associations between T2DM, hypertension, kidney dysfunction and carotid plaque, and further explore the combined effect of three diseases.

PATIENTS AND METHODS

We conducted a cross-sectional analysis among 3,815 community-dwelling adults in a Chinese atherosclerosis cohort. Estimated glomerular filtration rate (eGFR), hypertension and T2DM were evaluated as risk factors for carotid plaque. The presence, number and total area of carotid plaques were also assessed. Using logistic model, mutinomial logistic model and generalized linear regression model, the relationship between risk factors and carotid plaque was examined.

RESULTS

T2DM, hypertension, decreased GFR, and, inversely, eGFR, were independently associated with the presence, number and total area of carotid plaque. Stratified analysis by T2DM and hypertension showed T2DM attenuated the association between eGFR change and carotid plaque. There was a cumulative relationship between three risk factors and carotid plaque burden. The OR for the number of plaques was 1.0 (reference), 1.55 to 2.03, 1.94 to 3.14, and 3.69 (all P<0.05), respectively, for individuals with none, one, two, and three risk factors. Likewise, combining three risk factors was associated with greater increase in total plaque area (β, 20.63; 95% CI, 14.04-27.22).

CONCLUSION

The coexistence of decreased GFR, diabetes and hypertension is associated with increased risk of carotid plaque, and these comorbidities may contribute additively to the development of plaque.

Progression of Mild to Moderate Stenosis in the Internal Carotid Arteries of Patients With Ischemic Stroke

Background and purpose: Severe stenosis in the internal carotid artery may increase the risk of ischemic stroke. The factors that affect the progression of carotid artery stenosis in patients with ischemic stroke are poorly studied. No guidelines for the duration of follow-up of patients with ischemic stroke through carotid ultrasonography exist. Methods: In this retrospective study, 179 patients (108 men; mean age, 68 years) with ischemic stroke and mild to moderate stenosis in the internal carotid artery (ICA) were recruited. Carotid artery ultrasonography was performed over the period of January 2013 to June 2016 with a median follow-up of 36 months (mean 36.5 ± 3.5 months). The severity of carotid artery stenosis was estimated with the following equation: 1- (narrowest ICA diameter/total lumen diameter at the narrowest site). The severity of stenosis was categorized into grades I (0-29%), II (30-49%), III (50-59%), and IV (60-69%). The patient's stenosis grade was defined on the basis of the stenosis rate of the ICA side with most severe stenosis. Results: Stenosis progressed in 17.9% (64/358) of the vessels in 30.7% (55/179) of patients. The risk of stenosis progression increased as the severity of ICA stenosis increased. Patients with stenosis rates of above 50% are at a higher risk of stenosis progression than those with stenosis rate of < 50%. Relative to the patient group with an ICA stenosis rate of 0-29%, the adjusted odds ratios of stenosis progression were 2.33 (p = 0.03; 95% CI: 1.05~5.17), 3.50 (p = 0.09; 95% CI: 0.81~15.84), and 6.61 (p = 0.03; 95% CI: 1.01~39.61) in patient groups with ICA stenosis rates of 30-49%, 50-59%, and 60-69%, respectively. Hyper-LDL-cholesterolemia (Hyper-LDL-c) also increased the risk of stenosis progression, with an adjusted odds ratio of 2.22 (p = 0.03; 95% CI: 1.05~4.71). Conclusion: The rate of ICA stenosis progression increases with stenosis grade. Patients with ICA stenosis severity >50% and Hyper-LDL-c have high rates of stenosis progression. For the patients with stroke and ICA stenosis severity >50%, annual follow up through carotid artery ultrasonography may be necessary.

Restenosis After Carotid Endarterectomy in Patients with Paired Vein and Dacron Patch Reconstruction

This is an analysis of restenosis after bilateral carotid endarterectomy (CEA) with saphenous vein patch reconstruction on one side and Dacron patch reconstruction on the other. The possibility that differences in reconstruction geometry between vein and Dacron patched sides effected restenosis outcomes was evaluated as was the value of serial common carotid wall thickness measurements in predicting restenosis.

Between 1990 and 1997, 33 bilateral CEA were performed within one year on 22 men and 11 women using a greater saphenous vein patch on one side and a knitted Dacron patch on the other. Interoperative post-CEA geometry was measured. Follow-up was by duplex scans that included wall thickness measurements in the endarterectomized common carotid bulb.

Over a mean follow-up of 43 months 10 (30%) Dacron patched and one (3%) vein patched CEA developed?25% restenosis (p=0.001), seven (21%) Dacron patched and no vein patched CEA developed >50% restenosis (p=0.01) and four (12%) Dacron patched and no vein patched CEA developed >70% restenosis (p =0.1 1). The Kaplan-Meier cumulative >25% restenosis rates for Dacron and vein patched CEA were 22% and 0% at 2 years and 41% and 5% at 5 years respectively (p=0.002). The cumulative >50% restenosis rates for Dacron and vein patched CEA were 16% and 0% at 2 years and 34% and 0% at 5 years respectively (p = 0.003). The cumulative?70% restenosis rates for Dacron and vein patched CEA were 8% and 0% at 2 years and 20% and 0% at 5 years respectively (p = 0.02). For both patients with and without recurrent stenosis the mean within patient between sides differences of the diameters of the internal carotid, internal carotid bulb, common carotid bulb, and common carotid arteries and the lengths of the internal carotid and total patch segments were not significantly different and all were less than 5%. Common carotid bulb wall thickness measured at the time of identification of the nine unilateral Dacron patched CEA restenosis was 1.5 ±0.5 mm compared to 1.4 +0.4 mm (m ± 1 SD) for the contralateral vein patched CEA (p = 0.45 by paired t test). Dacron patched CEA have a significantly higher incidence of mild, moderate and severe restenosis than do saphenous vein patched CEA independent of systemic risk factors. The within patient equality of Dacron and vein patched carotid reconstruction geometry in patients with unilateral restenosis indicates that patch material is the major local risk factor, not adverse hemodynamics produced by variance in geometry. Common carotid bulb wall thickness measurements after CEA are not predictors or indicators of recurrent stenosis.

Prevalence and Risk Factors of Carotid Plaque Among Middle-aged and Elderly Adults in Rural Tianjin, China

Carotid plaque (CP) is associated with cardiovascular and cerebrovascular events. However, population-based studies with a large sample are rare in China, particularly those in the low-income population. We aimed to determine the prevalence of CP and the associated risk factors in the rural areas of northern China. Between April 2014 and June 2014, we recruited 3789 residents aged ≥45 years. B-mode ultrasonography was performed to measure the extent of CP. The prevalence of CP was 40.3% overall, 47.1% in men, and 35.4% in women (P < 0.001). The prevalence of CP increased with increasing age (P < 0.001). The participants with CP were more likely to have hypertension, diabetes, high total cholesterol (TC) levels, and high low-density lipoprotein-cholesterol levels and be a current smoker; however, they were less likely to be obese. Multiple logistic regression analysis, adjusted for confounders, indicated that age, male sex, hypertension, diabetes, current smoking, and high LDL-C levels were the independent risk factors for CP. There was a lower risk of CP with alcohol consumption. The findings suggest that managing the conventional risk factors is crucial to reduce the burden of cardiovascular and cerebrovascular diseases in the low-income population in China.

A Robotic Ultrasound Scanner for Automatic Vessel Tracking and Three-Dimensional Reconstruction of B-Mode Images

Locating and evaluating the length and severity of a stenosis is very important for planning adequate treatment of peripheral arterial disease (PAD). Conventional ultrasound (US) examination cannot provide maps of entire lower limb arteries in 3-D. We propose a prototype 3D-US robotic system with B-mode images, which is nonionizing, noninvasive, and is able to track and reconstruct a continuous segment of the lower limb arterial tree between the groin and the knee. From an initialized cross-sectional view of the vessel, automatic tracking was conducted followed by 3D-US reconstructions evaluated using Hausdorff distance, cross-sectional area, and stenosis severity in comparison with 3-D reconstructions with computed tomography angiography (CTA). A mean Hausdorff distance of 0.97 ± 0.46 mm was found in vitro for 3D-US compared with 3D-CTA vessel representations. To evaluate the stenosis severity in vitro, 3D-US reconstructions gave errors of 3%-6% when compared with designed dimensions of the phantom, which are comparable to 3D-CTA reconstructions, with 4%-13% errors. The in vivo system's feasibility to reconstruct a normal femoral artery segment of a volunteer was also investigated. These results encourage further ergonomic developments to increase the robot's capacity to represent lower limb vessels in the clinical context.

Significance of ABCA1 in human carotid atherosclerotic plaques

The ATP-binding cassette transporter A1 (ABCA1) is an important effector in the regulation of cholesterol efflux from cells. In this study, we assessed the role of ABCA1 in human carotid atherosclerotic plaques (CAPs). We found that ABCA1 and retinoid X receptor α (RXRα) mRNAs were significantly increased in the atherosclerotic plaques compared to control arteries. The increased ABCA1 mRNA correlated with that of RXRα in plaques. According to the modified American Heart Association plaque classification, atherosclerotic specimens were assigned to three grades, and ABCA1 and RXRα mRNA levels were compared across plaques of different grades. Resultantly, plaques of grade II and III exhibited higher mRNA levels than grade I, but there was no difference in mRNA levels between plaques of grade II and III. By contrast, ABCA1 and RXRα protein levels were notably reduced in plaques relative to control tissues. Similarly, plaques of grade II and III exhibited lower ABCA1 and RXRα protein levels than grade I, and there was no difference in protein levels between plaques of grade II and III. Our findings suggest that decreased ABCA1 protein plays a key role in the pathogenesis of CAP; the regulation of ABCA1 may be mediated by RXRα and ABCA1 mRNA levels may serve as an indicator for plaque stability.

Traditional cardiovascular risk factors explain the minority of the variability in carotid plaque

BACKGROUND AND PURPOSE

Subclinical atherosclerotic plaque is an important marker of increased vascular risk. Identifying factors underlying the variability in burden of atherosclerotic carotid plaque unexplained by traditional vascular risk factors may help target novel preventive strategies.

METHODS

As a part of the carotid substudy of the Northern Manhattan Study (NOMAS), 1790 stroke-free individuals (mean age, 69±9; 60% women; 61% Hispanic, 19% black, 18% white) were assessed for total plaque area (TPA) burden using 2-dimensional carotid ultrasound imaging. Multiple linear regression models were constructed. Model 1 used prespecified traditional risk factors: age, sex, low-density lipoprotein cholesterol, diabetes mellitus, pack-years of smoking, blood pressure, and treatment for blood pressure; and Model 2, an addition of socioeconomic and less traditional risk factors. The contributions of the components of the Framingham heart risk score and the NOMAS Global Vascular Risk Score to the TPA were explored.

RESULTS

Prevalence of carotid plaque was 58%. Mean TPA was 13±19 mm2. Model 1 explained 19.5% of the variance in TPA burden (R2=0.195). Model 2 explained 21.9% of TPA burden. Similarly, the Framingham heart risk score explained 18.8% and NOMAS global vascular risk score 21.5% of the TPA variance.

CONCLUSIONS

The variation in preclinical carotid plaque burden is largely unexplained by traditional and less traditional vascular risk factors, suggesting that other unaccounted environmental and genetic factors play an important role in the determination of atherosclerotic plaque. Identification of these factors may lead to new approaches to prevent stroke and cardiovascular disease.

Three-dimensional ultrasound scanning

The past two decades have witnessed developments of new imaging techniques that provide three-dimensional images about the interior of the human body in a manner never before available. Ultrasound (US) imaging is an important cost-effective technique used routinely in the management of a number of diseases. However, two-dimensional viewing of three-dimensional anatomy, using conventional two-dimensional US, limits our ability to quantify and visualize the anatomy and guide therapy, because multiple two-dimensional images must be integrated mentally. This practice is inefficient, and may lead to variability and incorrect diagnoses. Investigators and companies have addressed these limitations by developing three-dimensional US techniques. Thus, in this paper, we review the various techniques that are in current use in three-dimensional US imaging systems, with a particular emphasis placed on the geometric accuracy of the generation of three-dimensional images. The principles involved in three-dimensional US imaging are then illustrated with a diagnostic and an interventional application: (i) three-dimensional carotid US imaging for quantification and monitoring of carotid atherosclerosis and (ii) three-dimensional US-guided prostate biopsy.

Advance of studies on anti-atherosclerosis mechanism of berberine

Coptis Chinensis is a traditional Chinese medicine herb that has the effect of clearing heat and drying dampness, purging fire to eliminate toxin. Berberine is the main alkaloid of Coptis Chinensis, and, recent researches showed that berberine had the effect of anti-atherosclerosis. This paper reviewed the anti-atherosclerosis mechanism of berberine, which may be related to regulating lipids, anti-inflammation, decompression, reducing blood sugar, and inhibiting vascular smooth muscle cell proliferation.

Diabetes as a determinant of high-grade carotid artery stenosis: evaluation of 1,058 cases by Doppler sonography

Our objective was to investigate the association of risk factors, especially diabetes mellitus, with high-grade carotid artery stenosis. The study group was chosen from the patients who were sent to our Doppler ultrasonography laboratory for detecting the vascular anatomy. Doppler sonography was performed in 1,058 patients. High-grade carotid artery stenosis with a diameter reduction of 70% to 99% was detected in 89 patients. In the moderate and mild stenosis groups, we had 85 and 884 patients, respectively. Patients in the moderate stenosis group had a 40% to 69% carotid stenosis, and patients in the mild group had a 0% to 39% stenosis or normal ultrasonographic findings. Parameters of age, sex, alcohol, smoking, ischemic heart disease, hypertension, and diabetes were considered potential risk factors for stenosis. Multivariate logistic regression model was used as the statistical test in comparing the 3 groups. In the high-grade stenosis group, sex distribution was 34.8% female and 65.2% male with a mean age of 64.48 +/- 10.19 years. In the second and third groups these distributions were 51.8% female and 48.2% male with a mean age of 65.15 +/- 9.66 years, and 54.30% female and 45.70% male with a mean age 59.56 +/- 12.37, respectively. Diabetes mellitus (odds ratio [OR] = 2.77), ischemic heart disease (OR = 1.67), age (OR = 1.02), and male gender (OR = 1.75) were found to be significantly associated with high-grade carotid stenosis. As a cost-effective, noninvasive, easily performed, and fast technique, Doppler sonography is used in vascular evaluation of patients. Early diagnosis of carotid artery disease in patients with modifiable risk factors like diabetes may play an important role in the prevention of a consequent stroke.

Validation of 3D ultrasound vessel wall volume: an imaging phenotype of carotid atherosclerosis

Carotid atherosclerotic lesions are a major cause of stroke and the identification and quantification of such lesions in patients is important for the development of a better understanding of atherogenesis in high risk populations and for the design of studies to assess treatment efficacy. Our objective was to develop and validate a new three-dimensional ultrasound (3DUS) measurement or phenotype of carotid atherosclerosis, vessel wall volume (VWV), which is a three-dimensional measurement of vessel wall thickness and plaque within the carotid arteries measured in 3DUS images. To assess both intraobserver and interscan variability, 3DUS images were acquired from the right and left carotid arteries of ten subjects with carotid atherosclerosis scanned twice within a period of 2 wk. For both VWV and total plaque volume (TPV), an expert observer performed five measurement trials of all images acquired at baseline scan and 2-wk rescan with a 5-d period between measurement trials for images. Images were re-randomized for each measurement trial and both TPV and VWV were measured by observers who were blinded to subject identification for each time-point measurement. Coefficients of variation (COV) and intraclass correlation coefficients (ICC), for VWV measurements indicated higher intraobserver (scan COV = 4.6% ICC = 0.95, rescan COV = 3.4%, ICC = 0.96) and interscan reproducibility (COV = 5.7%, ICC = 0.85) than TPV measurements (intraobserver variability scan COV = 22.7% ICC = 0.85, rescan COV = 21.1% ICC = 0.88 and interscan variability, COV = 31.1%, ICC = 0.83), although absolute variances for both phenotypes were very similar (VWV = 90 mm3, TPV = 80 mm3).

Manual planimetric measurement of carotid plaque volume using three-dimensional ultrasound imaging

We investigated the utility of three manual planimetric methods to quantify carotid plaque volume. A single observer measured 15 individual plaques from 15 three-dimensional (3D) ultrasound (3D US) images of patients ten times each using three different planimetric approaches. Individual plaque volumes were measured (range: 32.6-597.1 mm3) using a standard planimetric approach (M1) whereby a plaque end was identified and sequential contours were measured. The same plaques were measured using a second approach (M2), whereby plaque ends were first identified and the 3D US image of the plaque was then subdivided into equal intervals. A third method (M3) was used to measure total plaque burden (range: 165.1-1080.0 mm3) in a region (+/- 1.5 cm) relative to the carotid bifurcation. M1 systematically underestimated individual plaque volume compared to M2 (V2 = V1 + 14.0 mm3, r = 0.99, p = 0.006) due to a difference in the mean plaque length measured. Coefficients of variance (CV) for M1 and M2 decrease with increasing plaque volume, with M2 results less than M1. Root mean square difference between experimental and theoretical CV for M2 was 3.2%. The standard deviation in the identification of the transverse location of the carotid bifurcation was 0.56 mm. CVs for plaque burden measured using M3 ranged from 1.2% to 7.6% and were less than CVs determined for individual plaque volumes of the same volume. The utility of M3 was demonstrated by measuring carotid plaque burden and volume change over a period of 3 months in three patients. In conclusion, M2 was determined to be a more superior measurement technique than M1 to measure individual plaque volume. Furthermore, we demonstrated the utility of M3 to quantify regional plaque burden and to quantify change in plaque volume.

Exaggerated carotid sinus massage responses are related to severe coronary artery disease in patients being evaluated for chest pain

BACKGROUND

Previous studies have reported that carotid sinus massage responses are associated with advancing age and carotid or coronary artery disease.

HYPOTHESIS

This study was undertaken to investigate the potential role of carotid sinus hypersensitivity as a marker for the presence of coronary artery disease, and especially left main stem disease, in patients who were referred for evaluation of chest pain.

METHODS

Toward this end, carotid sinus stimulation with simultaneous recordings of the electrocardiogram and aortic pressure was performed before coronary arteriography in 150 selected consecutive patients (mean age 59.4+/-9 years) who were referred for evaluation of chest pain.

RESULTS

Coronary artery disease was present in 118 patients (78.7%); of these, 35 had single-vessel disease, 35 had double-vessel disease, 33 had triple-vessel disease, and 15 had left main stem with or without such vessel disease. Carotid sinus hypersensitivity was found in 40 patients (26.6%). The incidence of hypersensitivity in patients with single-, double-, or triple-vessel disease and left main stem disease was 8.5, 14.2, 57.5, and 73.3%, respectively. Stepwise multiple logistic regression analysis revealed that left main stem disease was significantly and independently related to the presence of carotid sinus hypersensitivity (p < 0.05). In addition, the presence of hypersensitivity had 73.3% sensitivity, 86.2% specificity, and 96.3% negative predictive value for the presence of left main stem disease.

CONCLUSION

In patients being evaluated for suspected ischemic heart disease, carotid sinus massage responses are related to severe coronary disease. The absence of hypersensitivity may reflect absence of left main stem disease.

Morphological changes rather than flow-mediated dilatation in the brachial artery are better indicators of the extent and severity of coronary artery disease

OBJECTIVES

The aim of this study was to examine the relationship between morphological and functional parameters of the brachial and carotid arteries and the angiographic extent and severity of coronary artery stenosis in patients with severe coronary artery disease (CAD).

DESIGN

A cross-sectional study.

SETTING

University hospital.

MAIN OUTCOME MEASURES

Flow-mediated dilatation (FMD), intima-media thickness (IMT) in the brachial artery and atherosclerotic wall changes in the carotid arteries were measured by B-mode high-resolution ultrasound in 58 patients who had undergone coronary angiography.

RESULTS

A significant correlation was seen between the extent of coronary artery stenosis defined as the coronary angiographic score and both the mean brachial artery IMT and intima-media area (IMa; P = 0.01 and P = 0.04, respectively). There was no significant correlation between FMD and the extent of coronary artery stenosis. A significant correlation was seen between the mean carotid artery IMT and the mean brachial artery IMT (r = 0.30, P = 0.03). However, there was no significant correlation between FMD and the mean carotid artery IMT or IMa (r = 0.16, P = 0.23 and r = 0.17, P = 0.24, respectively).

CONCLUSIONS

Morphological but not functional parameters of the brachial artery are associated with the extent of coronary artery stenosis and atherosclerotic wall changes in the carotid arteries in patients with severe CAD. These findings indicate a potential of B-mode ultrasonography of morphological parameters in the brachial artery in the diagnostic and prognostic evaluation of patients with suspected CAD.

Quantification of carotid plaque volume measurements using 3D ultrasound imaging

An accurate and reliable technique used to quantify carotid plaque volume has practical importance in research and patient management. In this study, we develop and investigate a theoretical description of carotid plaque volume measurements made using three-dimensional (3D) ultrasound (US) images and compare it with experimental results. Multiple observers measured 48 3D US patient images of carotid plaque (13.2 to 544.0 mm(3)) by manual planimetry. Coefficients of variation in the measurement of plaque volume were found to decrease with increasing plaque size for both inter- (90.8 to 3.9%) and intraobserver (70.2 to 3.1%) measurements. Plaque volume measurement variability was found to increase with interslice distance (ISD), while the relative measurement accuracy remained constant for ISDs between 1.0 and 3.0 mm and then decreased. Root-mean-square (RMS) difference between our theoretical description of plaque volume measurement variance and the experimental results was 5.7%. Thus, our results support the clinical utility of measuring carotid plaque volume by manual planimetry noninvasively using 3D US.

Interrelation between the extent of atherosclerosis in the thoracic aorta, carotid intima-media thickness and the extent of coronary artery disease

Intima-media thickness (IMT) of the common carotid artery and atherosclerosis of the thoracic aorta have been shown to correlate with coronary artery disease (CAD). This study compares the relation between wall changes in the thoracic aorta and the carotid arteries and the angiographic severity and extent of atherosclerotic lesions in the coronary arteries in patients with verified CAD. Atherosclerotic wall changes in the carotid arteries and the thoracic aorta were measured by B-mode ultrasonography and transesophageal echocardiography (TEE), respectively, in 37 subjects aged 65+/-10 years with angiographically verified CAD. The mean value of the common carotid IMT of the right and left sides was 0.87+/-0.21 mm. All subjects had carotid plaques. TEE detected grades II-IV atherosclerotic plaques in the thoracic aorta in 32 of the 37 (86%) patients. A significant correlation was seen between the extent of coronary artery stenosis and aortic plaques score (r=0.46, p=0.008). Mean carotid IMT was also significantly correlated with coronary artery stenosis extent score (r=0.44, p=0.007). Moreover, a significant correlation was seen between the aortic plaque score and the mean carotid IMT (r=0.39, p=0.02). In conclusion, we found a clear and significant relationship between wall changes in the thoracic aorta, common carotid IMT and the angiographic extent of coronary artery stenosis in patients with severe CAD. These findings indicate a potential of B-mode ultrasonography of the carotid arteries and transesophageal echocardiographic aortic examination in the diagnostic and prognostic evaluation of patients with suspected CAD.

Theoretical and experimental quantification of carotid plaque volume measurements made by three-dimensional ultrasound using test phantoms

An accurate technique that exhibits low variability has practical importance for the quantification of carotid plaque volume. Such a technique is necessary to monitor plaque progression or regression that may result in response to nonsurgical therapy. In this study, we investigate the accuracy and variability of plaque volume measurement by three-dimensional ultrasound using vascular plaque phantoms over a range of 68.2 mm3 to 285.5 mm3. The agar plaques maintained a consistent cylindrical geometry with variations in the height, length, and echogenicity. The volume of each plaque was determined by water displacement. The three-dimensional (3D) ultrasound (US) images were acquired with a mechanical scanning system which creates a 3D US Cartesian volume, that was manipulated and viewed in any orientation, from a collection of conventional parallel two-dimensional (2D) US images. The plaque volumes were measured by serial 2D manual planimtery. The mean accuracy in plaque volume measurement was 3.1+/-0.9%. Variability in plaque volume measurement was calculated to be 4.0+/-1.0% and 5.1+/-1.4% for intraobserver and interobserver measurements, respectively. We have also developed a theoretical description for the variance in measurement of plaque volume using manual planimetry. Root-mean-square difference between experimentally and theoretically determined values of plaque volume fractional variance was 9%.

Three-dimensional ultrasound imaging

The objective of this article is to provide scientists, engineers and clinicians with an up-to-date overview on the current state of development in the area of three-dimensional ultrasound (3-DUS) and to serve as a reference for individuals who wish to learn more about 3-DUS imaging. The sections will review the state of the art with respect to 3-DUS imaging, methods of data acquisition, analysis and display approaches. Clinical sections summarize patient research study results to date with discussion of applications by organ system. The basic algorithms and approaches to visualization of 3-D and 4-D ultrasound data are reviewed, including issues related to interactivity and user interfaces. The implications of recent developments for future ultrasound imaging/visualization systems are considered. Ultimately, an improved understanding of ultrasound data offered by 3-DUS may make it easier for primary care physicians to understand complex patient anatomy. Tertiary care physicians specializing in ultrasound can further enhance the quality of patient care by using high-speed networks to review volume ultrasound data at specialization centers. Access to volume data and expertise at specialization centers affords more sophisticated analysis and review, further augmenting patient diagnosis and treatment.

Influence of ECG-triggered data acquisition on reliability for carotid plaque volume measurements with a magnetic sensor three-dimensional ultrasound system

Three-dimensional (3D) ultrasound reconstructions of the carotid arteries are based on multiple sections of two-dimensional data. Some 3D systems use an electrocardiography (ECG)-triggered data acquisition for 3D reconstructions of pulsatile vessels such as carotid arteries. No systematic comparison of 3D data, acquired with and without ECG triggering, has been reported. We used a new magnetic sensor system allowing freehand scanning for data acquisition. Our aim was to test the effect of ECG triggering on the reliability of plaque volume measurements in the carotid arteries. Data acquisition in the carotid arteries in 25 patients (one plaque from each patient) was performed using two different procedures for data acquisition: 1) a magnetic sensor system for a data acquisition without ECG-triggering, and 2) a magnetic sensor system with ECG-triggered data acquisition. All plaque volumes were measured using manual tracing of the outlines of the plaques. The following reliability data (mean values) were obtained: magnetic sensor system without ECG triggering: intrareader variability 13.3%, interreader variability 16.7%, follow-up variability 16.3%; magnetic sensor system with ECG triggering: intrareader variability 4.6%, interreader variability 4.5%, follow-up variability 5.2%. Carotid plaque volume measurements obtained using a magnetic sensor system with freehand scanning and ECG triggering is highly reliable. ECG triggering is necessary, because a magnetic sensor system without ECG triggering resulted in reduced reliability for plaque volume measurements.

Carotid sinus hypersensitivity in patients undergoing coronary arteriography: relation with the severity of carotid atherosclerosis and the extent of coronary artery disease

INTRODUCTION

The purpose of the present investigation was to study the precise relationship between carotid sinus hypersensitivity (CSH) and both the severity of carotid atherosclerosis and the extent of coronary artery disease in patients who were referred for evaluation for suspected ischemic heart disease.

METHODS AND RESULTS

Duplex echocardiography and coronary angiography were used to assess carotid and coronary artery atherosclerosis in 130 consecutive patients. Carotid sinus stimulation was performed before coronary arteriography with simultaneous recordings of the ECG and aortic pressure. Coronary artery disease was present in 103 patients (79%). Thirty patients (23.08%) had one-vessel disease (1-VD), 31 (23.85%) had 2-VD, 29 (22.31%) had 3-VD, and 13 patients (10%) had left main coronary artery disease. Carotid artery atherosclerosis was present in 100 patients (76.92%) and carotid disease (diameter stenosis > 50%) was present in 24 patients (18.46%). CSH was found in 33 patients (25%). The incidence of CSH was 9% in patients with carotid stenosis 1%-15%, 17% in patients with stenosis 16%-49%, 85% in patients with stenosis 50%-79%, and 100% in patients with stenosis > or = 80%. The incidence of CSH was 11%, 17%, 23%, 34%, and 62% in patients with no VD, 1-VD, 2-VD, 3-VD, and left main coronary artery disease, respectively. Stepwise multiple logistic regression analysis revealed that carotid disease and left main coronary artery disease were the most significant determinants of CSH (P < 0.001 and P = 0.013, respectively).

CONCLUSION

The incidence of CSH increased in proportion to the severity of carotid and coronary atherosclerosis. These data provide evidence that CSH is closely related to severe carotid atherosclerosis or left main coronary artery disease in patients being evaluated for suspected ischemic heart disease.

Evaluation and characterization of carotid plaque

Doppler sonography, combining high-resolution imaging and Doppler spectrum analysis, has proven to be the best choice for safe, noninvasive, low-cost screening for the etiology of stroke. With high-resolution imaging, plaque can be characterized relative to the risk for intraplaque hemorrhage, thought by many to be the precursor of plaque ulceration. Using high-resolution ultrasound, heterogeneous plaque has been shown to be associated with intraplaque hemorrhage. Criteria for distinguishing heterogeneous from homogeneous plaque are discussed, as are techniques for characterizing plaque. Several published articles strongly suggest that, when heterogeneous plaques are identified, the incidence of neurological symptoms and stroke on follow-up increases, relative to patients with homogeneous plaques. Additional long-term follow-up studies of heterogeneous plaque are needed. Most recently, carotid wall thickness has been evaluated as a physiological marker for atherosclerotic disease and as a gauge of the effectiveness of medical therapies. It is likely that carotid wall thickness will become important in the diagnosis and management of atherosclerosis. Radiologist are encouraged to learn this new form of ultrasound examination, which is reviewed briefly in this article.