Quantitative ultrasonic tissue characterization can identify high-risk atherosclerotic alteration in human carotid arteries

Transitions in vascular ultrasonography findings of temporal arteritis in a GCA case with progressive temporal headache and visual impairment

The European League Against Rheumatism and the American College of Rheumatology have stated that the halo sign on vascular ultrasonography (v-US) is relevant in diagnosing giant cell arteritis (GCA) and is equivalent to temporal artery biopsy. However, there are only a few reports about transitions in v-US findings after glucocorticoid (GC) therapy. We report the transitions in the v-US findings in a case of GCA after GC therapy. The patient had rapidly progressive symptoms, and there were concerns about blindness. After GC therapy, we first observed improvement in headache and visual impairment symptoms within 1 week, followed by rapid improvement in laboratory findings within 2 weeks. Subsequently, there were improvements in v-US findings after more than 2 months. In conclusion, these findings showed a dissociation between improvements in clinical symptoms and v-US findings of the temporal artery. Additionally, this case suggests that regular examination of v-US findings is useful in evaluating GCA with evident vascular wall thickness before GC therapy.

Comparing Focused-Tracked and Plane Wave-Tracked ARFI Log(VoA) In Silico and in Application to Human Carotid Atherosclerotic Plaque, Ex Vivo

A significant risk factor for ischemic stroke is carotid atherosclerotic plaque that is susceptible to rupture, with rupture potential conveyed by plaque morphology. Human carotid plaque composition and structure have been delineated noninvasively and in vivo by evaluating log(VoA), a parameter derived as the decadic log of the second time derivative of displacement induced by an acoustic radiation force impulse (ARFI). In prior work, ARFI-induced displacement was measured using conventional focused tracking; however, this requires a long data acquisition period, thereby reducing framerate. We herein evaluate if ARFI log(VoA) framerate can be increased without a reduction in plaque imaging performance using plane wave tracking instead. In silico, both focused- and plane wave-tracked log(VoA) decreased with increasing echobrightness, quantified as signal-to-noise ratio (SNR), but did not vary with material elasticity for SNRs below 40 dB. For SNRs of 40-60 dB, both focused- and plane wave-tracked log(VoA) varied with SNR and material elasticity. Above 60 dB SNR, both focused- and plane wave-tracked log(VoA) varied with material elasticity alone. This suggests that log(VoA) discriminates features according to a combination of their echobrightness and mechanical property. Further, while both focused- and plane-wave tracked log(VoA) values were artifactually inflated by mechanical reflections at inclusion boundaries, plane wave-tracked log(VoA) was more strongly impacted by off-axis scattering. Applied to three excised human cadaveric carotid plaques with spatially aligned histological validation, both log(VoA) methods detected regions of lipid, collagen, and calcium (CAL) deposits. These findings support that plane wave tracking performs comparably to focused tracking for log(VoA) imaging and that plane wave-tracked log(VoA) is a viable approach to discriminating clinically relevant atherosclerotic plaque features at a 30-fold higher framerate than by focused tracking.

Spectral analysis of ultrasound backscatter for non-invasive measurement of plaque composition

Carotid atherosclerotic plaque composition may be an important indication of patient risk for future cerebrovascular events. Ultrasound spectral analysis has the potential to provide a robust measure of plaque composition in vivo if the backscatter transfer function can be sufficiently isolated from the effects of attenuation from overlying tissue, receive and transmit transfer functions from the ultrasound system and transducer, and diffraction. This study examines the usefulness of the nonlinearly generated second harmonic portion of the backscatter signal and the effects of a variety of attenuation compensation techniques for noninvasively characterizing human carotid plaque using spectral analysis and machine learning. Post-beamformed ultrasound backscatter radiofrequency (RF) data were acquired from 6 normal subjects and 119 carotid endarterectomy patients prior to surgery. Plaque obtained following surgery was histologically processed, and regions of interest (ROI) corresponding to homogenous tissue types (fibrous/fibro-lipidic, hemorrhagic and/or necrotic core and calcified) were selected from RF data. Both the harmonic and fundamental power spectra for each ROI was obtained and normalized by data from a uniform phantom (0.5 dB/cm-MHz slope of attenuation). Additional attenuation compensation approaches were compared to simply using the reference phantom: (1) optimum power spectral shift estimation, (2) one-step adventitial, or (3) two-step adventitial. Spectral parameters extracted from both the fundamental and harmonic estimates of the backscatter transfer function of 363 ROI's from 152 plaque specimens were used to train and test random forest and support vector machine classification models. The best results came from using spectral parameters derived from both the fundamental and second harmonic bands with a predictive accuracy of 65-68%, kappa statistic of 0.49-0.54, and accuracies of 84% for fibrous, 68-74% for hemorrhagic and/or necrotic core, and 78-81% for calcified ROI's. The result indicated that the nonlinearly generated second harmonic portion of backscatter is useful for carotid plaque tissue characterization and that a reference phantom approach with a 0.5 dB/cm-MHz slope of attenuation works as well as more complicated approaches.

Forward-Looking Multimodal Endoscopic System Based on Optical Multispectral and High-Frequency Ultrasound Imaging Techniques for Tumor Detection

We developed a forward-looking (FL) multimodal endoscopic system that offers color, spectral classified, high-frequency ultrasound (HFUS) B-mode, and integrated backscattering coefficient (IBC) images for tumor detection in situ. Examination of tumor distributions from the surface of the colon to deeper inside is essential for determining a treatment plan of cancer. For example, the submucosal invasion depth of tumors in addition to the tumor distributions on the colon surface is used as an indicator of whether the endoscopic dissection would be operated. Thus, we devised the FL multimodal endoscopic system to offer information on the tumor distribution from the surface to deep tissue with high accuracy. This system was evaluated with bilayer gelatin phantoms which have different properties at each layer of the phantom in a lateral direction. After evaluating the system with phantoms, it was employed to characterize forty human colon tissues excised from cancer patients. The proposed system could allow us to obtain highly resolved chemical, anatomical, and macro-molecular information on excised colon tissues including tumors, thus enhancing the detection of tumor distributions from the surface to deep tissue. These results suggest that the FL multimodal endoscopic system could be an innovative screening instrument for quantitative tumor characterization.

Echolucency of carotid plaque is useful for selecting high-risk patients with chronic coronary artery disease who benefit from intensive lipid-lowering therapy

BACKGROUND

Ultrasound assessment of the carotid artery provides prognostic information on coronary events. This study examined whether ultrasound assessments of plaque echolucency of the carotid artery are useful for identifying patients with coronary artery disease (CAD) who are at high risk but could benefit from lipid-lowering therapy for secondary prevention.

METHODS

Ultrasound assessment of carotid plaque echolucency with integrated backscatter (IBS) analysis was performed in 393 chronic CAD patients with low-density lipoprotein cholesterol (LDL-C) levels <100 mg/dL on statin therapy. All patients were prospectively followed up for a maximum of 96 months or until the occurrence of one of the following coronary events: cardiac death, nonfatal myocardial infarction, or unstable angina pectoris requiring unplanned revascularization.

RESULTS

During the follow-up period, 45 coronary events occurred. Patients were stratified by IBS (≤-16.3 or >-16.3 dB, median value) and LDL-C level (<70 or 70-99 mg/dL). Multivariate Cox proportional hazards analysis showed that patients with lower IBS and LDL-C 70-99 mg/dL had significantly higher probabilities of coronary events compared with those with higher IBS and LDL-C <70 mg/dL, after adjustment for a baseline model of risk factors (hazard ratio 5.15; 95% confidence interval 1.21-22.0, p = 0.03). In contrast, patients with lower IBS and LDL-C <70 mg/dL had an improved prognosis comparable with those with higher IBS. Addition of LDL-C levels to the baseline model of risk factors improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) in patients with lower IBS (NRI, 0.44, p = 0.04; and IDI, 0.035, p < 0.01), but not in those with higher IBS.

CONCLUSIONS

Evaluation of echolucency of the carotid artery was useful for selecting CAD patients at high risk of secondary coronary events but who could benefit from lipid-lowering therapy.

Usefulness of Carotid Ultrasonography for Risk Stratification of Cerebral and Cardiovascular Disease

Carotid ultrasonography is useful for the assessments of the risk stratification for stroke or coronary artery disease, because it is a simple, repeatable, and noninvasive procedure. The carotid intima-media thickness (IMT), which is assessed using carotid ultrasonography, is a widely used surrogate marker for the severity of atherosclerosis. Several large clinical studies showed that increased carotid IMT is associated with the future stroke or cardiovascular events. In addition, in many clinical trials, it has been adopted for surrogate markers of clinical endpoints of medical intervention. Moreover, carotid ultrasonography allows the measurement of the presence and characteristics of plaques and the severity of carotid artery stenosis. The unstable morphology of plaque, such as hypoechoic, ulcer, and mobility, is associated with future ischemic stroke events. The screening tool of asymptomatic carotid artery stenosis is also important, although whether routine carotid ultrasonography assessment is recommended in the general population remains controversial. The screening of carotid artery stenosis using ultrasonography is essential for not only daily clinical settings but also management of patients with acute ischemic stroke. The patients with atherothrombotic stroke with severe internal carotid artery stenosis should be considered to surgical intervention, and duplex ultrasound approach is important to estimate for the severity of carotid stenosis. Physicians should keep in mind the usefulness of carotid ultrasonography for risk stratification of cerebral and cardiovascular disease based on various aspects. In addition, visual assessment or dynamic changes using carotid ultrasonography could provide the various and valuable insights in clinical settings.

Clinical utility of carotid ultrasonography: Application for the management of patients with diabetes

Carotid ultrasonography is a non-invasive, simple and inexpensive modality to assess the severity of atherosclerosis. This article reviews related articles, summarizes the rationale for the application of carotid ultrasonography in clinical practice, and addresses the features and the limitations of carotid ultrasonography in cardiovascular risk prediction. Numerous large studies have confirmed that various carotid ultrasound measures, such as carotid intima-media thickness, the presence or absence of carotid plaque, plaque number and plaque area, can be independent predictors of cardiovascular diseases in individuals with and without diabetes mellitus. Furthermore, many studies showed that the use of carotid intima-media thickness (especially maximum intima-media thickness, including plaque thickness) and/or carotid plaque in addition to traditional risk factors significantly improved the prediction of the occurrence of cardiovascular diseases, while controversy remains. Several studies showed that the progression of carotid intima-media thickness also can be a surrogate end-point of cardiovascular events. However, the accumulated evidence has not been sufficient. Further study with sufficient power should be carried out. As plaque disruption, which plays a crucial role in the pathogenesis of cardiovascular events, is dependent on the content of lipid in the atheroma and the thickness of the fibrous cap, tissue characterization of a plaque might be useful for determining its fragility. Interestingly, recent studies have shown that ultrasonic tissue characterization of carotid lesions could improve the prediction ability of future cardiovascular diseases. Thus, carotid ultrasonography is a useful modality for better clinical practice of atherosclerosis in patients with diabetes.

Analysis of Two Quantitative Ultrasound Approaches

There are two well-known ultrasonic approaches to extract sets of quantitative parameters: Lizzi-Feleppa (LF) parameters: slope, intercept, and midband; and quantitative ultrasound (QUS)-derived parameters: effective scatterer diameter (ESD) and effective acoustic concentration (EAC). In this study, the relation between the LF and QUS-derived parameters is studied theoretically and experimentally on ex vivo mouse livers. As expected from the theory, LF slope is correlated to ESD ([Formula: see text]), and from experimental data, LF midband is correlated to EAC ([Formula: see text]). However, LF intercept is not correlated to ESD ([Formula: see text]) nor EAC ([Formula: see text]). The unexpected correlation observed between LF slope and EAC ([Formula: see text]) results likely from the high correlation between ESD and EAC due to the inversion process. For a liver fat percentage estimation, an important potential medical application, the parameters presenting the better correlation are EAC ([Formula: see text]) and LF midband ([Formula: see text]).

Clinical Utility of Carotid Ultrasonography in the Prediction of Cardiovascular Events in Patients with Diabetes: A Combined Analysis of Data Obtained in Five Longitudinal Studies

Aim: It remains unclear whether measures used in carotid ultrasonography such as the intima–media thickness (IMT) and ultrasonic tissue characterization of the carotid using the gray-scale median (GSM) can add prognostic information beyond the conventional cardiovascular risk markers in pati ents with diabetes.

Methods: This study employed a combined analysis of data obtained in five longitudinal studies including a total of 3263 patients with diabetes but without apparent cardiovascular disease (CVD) at baseline. The associations between carotid ultrasonography measures and the first occurrence of CVD (488 cases), which were defined as cardiovascular death, coronary artery diseases, stroke, or peripheral artery disease, were analyzed.

Results: Common carotid artery (CCA)-mean-IMT, CCA-max-IMT, Max-IMT, plaque-GSM, and the presence of low-GSM echolucent plaques at baseline were prognostic factors for CVD even after adjustment for conventional risk factors. Time-dependent receiver-operating-characteristic (ROC) curve analysis indicated that the use of CCA-mean-IMT, CCA-max-IMT, and Max-IMT in addition to the conventional risk factors improved significantly the prediction of occurrence of CVD. Increments in the CCA-mean-IMT (hazard ratio [HR] 2.37 for every 0.1-mm/year increment [95% confidence interval [CI]: 1.63–3.47], p < 0.001), Max-IMT (HR 1.51 for every 0.1-mm/year increment [95% CI: 1.07–2.14], p = 0.020), and Mean-GSM (HR 0.22 for every 10-U/year increment [95% CI: 0.06–0.76], p = 0.016) during the observation period were also prognostic factors for CVD even after adjusting for the baseline value of the respective measure.

Conclusions: Addition of carotid ultrasonography measures to conventional risk factors significantly improved the stratification of patients by cardiovascular risk. Changes over time in carotid ultrasonography measures may be used as therapeutic outcome measures.

Abbreviations: CAC, coronary artery calcium; CCA, common carotid artery; CVD, cardiovascular disease; DM, diabetes mellitus; FRS,Framingham Risk Score; GSM, gray-scale median; HR, hazard ratio; IMT, intima–media thickness; PAD, peripheral artery disease

American Society of Echocardiography Report

Noninvasive measures of atherosclerosis have emerged as adjuncts to standard cardiovascular disease (CVD) risk factors in an attempt to refine risk stratification and the need for more aggressive preventive strategies. Two such approaches, carotid artery imaging and brachial artery reactivity testing (BART), are ultrasound based. Numerous carotid artery imaging protocols have been used, and methodologic aspects are described in detail in this review. The panel recommends that protocols: (1) use end-diastolic (minimum dimension) images for intimal-medial thickness (IMT) measurements; (2) provide separate categorization of plaque presence and IMT; (3) avoid use of a single upper limit of normal for IMT because the measure varies with age, sex, and race; and (4) incorporate lumen measurement, particularly when serial measurements are performed to account for changes in distending pressure. Protocols may vary in the number of segments wherein IMT is measured, whether near wall is measured in addition to far wall, and whether IMT measurements are derived from B-mode or M-mode images, depending on the application. BART is a technique that requires meticulous attention to patient preparation and methodologic detail. Its application is substantially more challenging than is carotid imaging and remains largely a research technique that is not readily translated into routine clinical practice.

Ultrasound and Biochemical Diagnostic Tools for the Characterization of Vulnerable Carotid Atherosclerotic Plaque

Stroke is a leading cause of morbidity and mortality worldwide, and characterization of vulnerable carotid plaque remains the spearhead of scientific research. Plaque destabilization, the key factor that induces the series of events leading to the clinical symptoms of carotid artery disease, is a consequence of complex mechanical, structural and biochemical processes. Novel imaging and molecular markers have been studied as predictors of disease outcome with promising results. The aim of this review is to present the current state of research on the association between ultrasound-derived echogenicity indices and blood parameters indicative of carotid plaque stability and activity. Bibliographic research revealed that there are limited available data. Among the biomarkers studied, those related to oxidative stress, lipoproteins and diabetes/insulin resistance are associated with echolucent plaques, whereas adipokines are associated with echogenic plaques. Biomarkers of inflammation and coagulation have not exhibited any conclusive relationship with plaque echogenicity, and it is not possible to come to any conclusion regarding calcification-, apoptosis- and neo-angiogenesis-related parameters because of the extremely limited bibliographic data.

Comparison of carotid plaque tissue characteristics in patients with acute coronary syndrome or stable angina pectoris: assessment by iPlaque, transcutaneous carotid ultrasonography with integrated backscatter analysis

Background

The association of the tissue characteristics of carotid plaques with coronary artery disease has attracted interest. The present study compared the tissue characteristics of carotid plaques in patients with acute coronary syndrome (ACS) with those in patients with stable angina pectoris (SAP) using the iPlaque system, which is based on ultrasound integrated backscatter.

Methods and results

Carotid ultrasound examinations were performed in 26 patients with ACS, and 38 age- and gender-matched patients with SAP. Neither plaque area nor maximal intima-media thickness differed significantly between the two groups. However, the average integrated backscatter value within the plaque was greater in the ACS patients than in the SAP patients. iPlaque analysis revealed that the percentage blue area (lipid pool) was greater in the ACS patients than in the SAP patients (43.4 ± 11.2 vs 18.3 ± 10.3 %, p < 0.0001), and that the percentage green area (fibrosis) was lower in the ACS than in the SAP patients (7.5 ± 7.5 % vs 20.7 ± 11.7 %, p < 0.0001).

Conclusions

The lipid component of carotid plaques is greater in ACS patients than in SAP patients. Our iPlaque system provides a useful and feasible method for the tissue characterization of carotid plaques in the clinical setting.

Aortic Intima-Media Thickness as an Early Marker of Atherosclerosis in Children With Inflammatory Bowel Disease

OBJECTIVES

The aims of this study were to determine the presence of endothelial dysfunction by measuring aortic intima-media thickness (aIMT) and carotid intima-media thickness (cIMT) and to evaluate the role of traditional risk factors for premature atherosclerosis in children with inflammatory bowel disease (IBD).

METHODS

Thirty-four children with IBD (25 Crohn disease [CD] and 9 ulcerative colitis [UC]; mean age 11.1 years) and 27 healthy subjects matched for sex and age were enrolled. In all of the patients, demographic characteristics and risk factors for atherosclerosis (age, sex, body mass index, blood pressure, dyslipidemia, active and passive smoking, and family history for cardiovascular diseases), CD and UC clinical activity scores, and inflammatory markers were evaluated. aIMT and cIMT were measured by high-resolution B-mode ultrasound.

RESULTS

aIMT was significantly higher in patients than in controls (P < 0.0005). No significant differences were found for cIMT, although the carotid thickness was higher in patients with IBD than in healthy subjects. At a univariate analysis, inflammatory markers levels and tobacco smoking exposure were significantly related to higher aIMT values, whereas in a multivariate regression model, the inflammatory status was the only independent variable correlated with high aIMT.

CONCLUSIONS

aIMT is an earlier marker of preclinical atherosclerosis than cIMT in young children with active IBD. The inflammatory status and the smoking exposure are significantly correlated with the premature endothelial dysfunction. These data emphasize the importance of controlling the chronic intestinal inflammation and endorsing smoke-free environments for children and adolescents with IBD.

An integrated backscatter ultrasound technique for the detection of coronary and carotid atherosclerotic lesions

The instability of carotid and coronary plaques has been reported to be associated with acute coronary syndrome, strokes and other cerebrovascular events. Therefore, recognition of the tissue characteristics of carotid and coronary plaques is important to understand and prevent coronary and cerebral artery disease. Recently, an ultrasound integrated backscatter (IB) technique has been developed. The ultrasound IB power ratio is a function of the difference in acoustic characteristic impedance between the medium and target tissue, and the acoustic characteristic impedance is determined by the density of tissue multiplied by the speed of sound. This concept allows for tissue characterization of carotid and coronary plaques for risk stratification of patients with coronary and cerebral artery disease. Two- and three-dimensional IB color-coded maps for the evaluation of tissue components consist of four major components: fibrous, dense fibrosis, lipid pool and calcification. Although several ultrasound techniques using special mathematical algorithms have been reported, a growing body of literature has shown the reliability and usefulness of the IB technique for the tissue characterization of carotid and coronary plaques. This review summarizes concepts, experimental procedures, image reliability and the application of the IB technique. Furthermore, the IB technique is compared with other techniques.

Echolucent Carotid Plaque is Associated with Future Renal Dysfunction in Patients with Stable Coronary Artery Disease

AIM

Functional and structural abnormalities of the peripheral arteries are associated with renal dysfunction, independent of the presence of renal artery stenosis. This study investigated whether echolucent carotid plaque is associated with a future decline in the renal function in patients with coronary artery disease (CAD).

METHODS

Ultrasound assessments of carotid plaque echolucency with integrated backscatter (IBS) analyses were performed in 327 patients with stable CAD and carotid plaque who exhibited a normal renal function (estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m(2)) at baseline. A lower IBS value reflects the presence of echolucent and lipid-rich unstable plaque. All patients were followed up for 36 months or until the occurrence of renal dysfunction, defined as an eGFR of ＜45 mL/min/1.73 m(2).

RESULTS

During the follow-up period, 39 patients developed renal dysfunction. A multivariate logistic regression analysis showed that the presence of carotid plaque with a low IBS value was significantly associated with progression to renal dysfunction (odds ratios 0.48; 95% CI 0.30-0.78, p= 0.003). In addition, carotid plaque with a low IBS value had a significant incremental effect on the predictive value of known risk factors for renal dysfunction in analyses using c-statistics (AUC of the baseline risk model with and without IBS: 0.83 vs. 0.79, respectively, p=0.04), net reclassification improvement (index=0.549, p=0.001) and integrated discrimination improvement (index=0.068, p=0.002).

CONCLUSIONS

Echolucency of the carotid arteries is associated with future renal dysfunction in patients with stable CAD, indicating that the mechanisms related to plaque instability may be involved in the onset of renal dysfunction.

The risk factors associated with ultrasonic tissue characterization of carotid plaque in type 2 diabetic patients

AIMS

Little is known about the related factors of plaque echogenicity in diabetic subjects.

METHODS

This was a single-center, retrospective, study investigating a subgroup of patients of a previously published trial. We enrolled 179 middle-aged and older Japanese type 2 diabetic patients with carotid plaque, and examined the parameters related with echogenicity of carotid plaque evaluated by gray-scale median (GSM).

RESULTS

Proportion of males and body mass index (BMI) were significantly higher and HDL-cholesterol was significantly lower in the patients with low GSM (< 48) plaques (n = 89) as compared to those without it (n = 90). A multiple logistic regression analysis with gender, BMI, and HDL-cholesterol as independent variables and the presence of low GSM plaques as an objective variable showed that male (odds ratio (OR) 2.36, 95%CI 1.05-5.31, p = 0.037) and BMI (OR 1.12 [1.01-1.24], p = 0.029) were independently associated with low GSM plaques. Another multiple logistic regression analysis with gender, BMI, and low-HDL-cholesterolemia (HDL-C < 40 mg/dl) as independent variables showed that low-HDL-cholesterolemia (OR 2.30 [1.03-5.13], p = 0.042) and BMI (OR 1.11 [1.00-1.22], p = 0.046) were independently associated with low GSM plaques.

CONCLUSIONS

Our study suggests that gender, BMI and low-HDL-cholesterol are important determinants of the content of the vascular wall in diabetic subjects.

Ultrasonic assessment of myocardial microstructure

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. Ultrasonic assessments of cardiac tissue can include analyses of backscatter signal intensity within a given region of interest. Previously established techniques have relied predominantly on the integrated or mean value of backscatter signal intensities, which may be susceptible to variability from aliased data from low frame rates and time delays for algorithms based on cyclic variation. Herein, we describe an ultrasound-based imaging algorithm that extends from previous methods, can be applied to a single image frame and accounts for the full distribution of signal intensity values derived from a given myocardial sample. When applied to representative mouse and human imaging data, the algorithm distinguishes between subjects with and without exposure to chronic afterload resistance. The algorithm offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Vulnerable atherosclerotic carotid plaque evaluation by ultrasound, computed tomography angiography, and magnetic resonance imaging: an overview

Ischemic syndromes associated with carotid atherosclerotic disease are often related to plaque rupture. The benefit of endarterectomy for high-grade carotid stenosis in symptomatic patients has been established. However, in asymptomatic patients, the benefit of endarterectomy remains equivocal. Current research seeks to risk stratify asymptomatic patients by characterizing vulnerable, rupture-prone atherosclerotic plaques. Plaque composition, biology, and biomechanics are studied by noninvasive imaging techniques such as magnetic resonance imaging, computed tomography, ultrasound, and ultrasound elastography. These techniques are at a developmental stage and have yet to be used in clinical practice. This review will describe noninvasive techniques in ultrasound, magnetic resonance imaging, and computed tomography imaging modalities used to characterize atherosclerotic plaque, and will discuss their potential clinical applications, benefits, and drawbacks.

Echocardiographic integrated backscatter for assessing reduction of aortic valve calcifications by R-568 in a rat model of chronic kidney disease

Chronic kidney disease (CKD) and secondary hyper-parathyroidism are associated with calcific aortic valve disease (CAVD). Innovative modalities for imaging CAVD are warranted. Our aim was to use echocardiographic calibrated integrated backscatter (cIB) to quantitatively determine the preventive effect of the calcimimetic R-568 on CAVD in a CKD rat model, and to compare the results with those of micro-computed tomography and histology. Thirty-six male Wistar rats were followed for 7 wk. Rats were divided into four groups with respect to treatment: (1) adenine 0.5% to induce CKD + vehicle; (2) adenine + R-568 (30 mg/kg/d); (3) control, normal diet + vehicle; (4) controls, normal diet + R-568. At week 7, cIB values of the aortic valve were significantly lower in R-568-treated group 2 than in vehicle-treated group 1. This was confirmed by the significantly lower calcified volume observed on micro-computed tomography and the calcified area observed on histology. There were no significant differences in fractional area change and aortic valve area between groups. In conclusion, echocardiographic cIB was able to quantitatively assess a reduction in CAVD by R-568 in a rat model of CKD.

Ultrasonic tissue characterization of carotid plaque improves the prediction of cardiovascular events in diabetic patients: a pilot study

OBJECTIVE

The aim of this study is to evaluate whether noninvasive ultrasonic tissue characterization of carotid plaque using integrated backscatter (IBS) analysis can be a predictor of future cardiovascular events (CVE) in asymptomatic type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

We prospectively evaluated the association between Calibrated-IBS value, an ultrasonic marker for tissue characteristics of carotid plaque, and CVE in 85 asymptomatic type 2 diabetic patients with carotid plaque.

RESULTS

The median follow-up period was 7.9 years, and there were 20 new CVE. The risk of CVE was significantly higher in the subjects with low Calibrated-IBS values (<-17.1 dB; n = 42) as compared with those with high values (≥-17.1 dB; n = 43) (P = 0.004, log-rank test). Cox proportional hazards regression analysis revealed that both Calibrated-IBS value (hazard ratio [HR] 0.802 [95% CI 0.710-0.906]; P < 0.0001) and plaque thickness (1.938 [1.170-3.213]; P = 0.010) were independently associated with CVE, even after adjustment for the 10-year risk for a general cardiovascular disease estimated by Framingham risk scoring (FRS). Time-dependent receiver operating characteristic curve analysis for CVE at 10 years after the baseline examinations revealed that area under the curve for Calibrated-IBS was 0.76 (0.60-0.90) and substantially higher than those for plaque thickness (0.60 [0.45-0.79]) and FRS (0.60 [0.40-0.78]). These analyses also revealed that the addition of both plaque thickness and Calibrated-IBS value to conventional risk factors significantly improved the event prediction.

CONCLUSIONS

Calibrated-IBS value could improve the risk prediction of CVE in asymptomatic type 2 diabetic patients with carotid plaque.

Ultrasound assessment of brachial endothelial vasomotor function in addition to carotid plaque echolucency for predicting cardiovascular events in patients with coronary artery disease

BACKGROUND

Single assessment of either flow-mediated vasodilatation of the brachial artery (FMD) or carotid plaque echolucency provides prognostic information for both cerebrovascular and coronary events.

OBJECTIVES

This study tested the hypothesis that combined assessment using carotid plaque echolucency and FMD may have an additive effect when predicting cardiovascular events in patients with coronary artery disease (CAD).

METHODS

Ultrasound assessment of carotid plaque echolucency with integrated backscatter (IBS) analysis (calibrated IBS=intima-media IBS value-adventitia IBS) and FMD was performed in 547 consecutive patients with CAD. All the study patients were followed up prospectively for a period of ≤ 60 months until the occurrence of one of the following cardiovascular events: cardiac death, non-fatal myocardial infarction, unstable angina requiring coronary revascularization, or ischemic stroke.

RESULTS

During a mean follow-up period of 52 ± 10 months, 69 cardiovascular events occurred. A multivariate Cox proportional hazard model after 1000 bootstrapped resampling demonstrated that calibrated IBS and FMD were significant, independent predictors of future cardiovascular events after adjustment for known risk factors (calibrated IBS, HR 0.88, 95% CI 0.83-0.93; FMD, HR 0.76, 95% CI 0.68-0.85). The c-statistics, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses showed that the combination of calibrated IBS and FMD values had a greater incremental effect on the predictive value of known risk factors for cardiovascular events.

CONCLUSIONS

Combined assessment of brachial endothelial function and carotid plaque echolucency is an independent predictor of cardiovascular events and improves risk prediction when added to known risks.

Quantitative ultrasound visualization of cell death: emerging clinical applications for detection of cancer treatment response

Differentiable echogeneities exhibited by living and dead cells enables the monitoring of cell death response via quantitative ultrasound techniques at high-frequencies and recently at clinical range frequencies. Such capability can be potentially employed to provide rapid and quantitative functional information in real time, and at the patient bedside for evaluating therapy response early following treatment. This paper summarizes backgrounds on quantitative ultrasound visualization of cell death and highlights its potential capabilities for monitoring cancer treatment response, where favorable results have been reported, according to a recent pilot clinical study.

Current techniques for MR imaging of atherosclerosis

Vessel wall imaging of large vessels has the potential to identify culprit atherosclerotic plaques that lead to cardiovascular events. Comprehensive assessment of atherosclerotic plaque size, composition, and biological activity is possible with magnetic resonance imaging (MRI). Magnetic resonance imaging of the atherosclerotic plaque has demonstrated high accuracy and measurement reproducibility for plaque size. The accuracy of in vivo multicontrast MRI for identification of plaque composition has been validated against histological findings. Magnetic resonance imaging markers of plaque biological activity such as neovasculature and inflammation have been demonstrated. In contrast to other plaque imaging modalities, MRI can be used to study multiple vascular beds noninvasively over time. In this review, we compare the status of in vivo plaque imaging by MRI to competing imaging modalities. Recent MR technological improvements allow fast, accurate, and reproducible plaque imaging. An overview of current MRI techniques required for carotid plaque imaging including hardware, specialized pulse sequences, and processing algorithms are presented. In addition, the application of these techniques to coronary, aortic, and peripheral vascular beds is reviewed.

Quantitative evaluation of coronary artery wall echogenicity by integrated backscatter analysis in Kawasaki disease

BACKGROUND

Coronary artery wall echogenicity increases on echocardiograms during the acute phase of Kawasaki disease (KD). According to this background, echogenicity of the coronary artery wall in patients with KD is quantified by using integrated backscatter (IB) analysis.

METHODS

IB analysis is a quantitative method for evaluating echogenicity. We examined the value of IB in the wall of the left anterior descending coronary artery and compared it with that in adjacent intracardiac blood as a measure of background. The difference between these values is represented as corrected IB for the coronary artery wall.

RESULTS

Corrected IB for the coronary artery wall was higher in patients with KD than in controls (KD with pre-immunoglobulin therapy vs. controls: 27.4 +/- 5.3 dB vs. 22.0 +/- 3.5 dB, P < .05) and in patients with coronary enlargement after intravenous immunoglobulin (with vs. without coronary enlargement, 29.2 +/- 5.2 dB vs. 24.1 +/- 5.5 dB, P < .05).

CONCLUSION

The magnitude of IB from the coronary artery wall reflects the effectiveness of immunoglobulin therapy. Furthermore, this method and its value might be useful to predict the occurrence of coronary enlargement in patients with KD.

Aortic intima media thickness is an early marker of atherosclerosis in children with type 1 diabetes mellitus

OBJECTIVE

To compare aortic intima media thickness (aIMT) to carotid intima media thickness (cIMT) as a marker of early atherosclerosis in children with type 1 diabetes mellitus and to examine the associations of aIMT to known cardiovascular risk factors.

STUDY DESIGN

66 children with type 1 diabetes mellitus (age, 14.1 +/- 2.5 years; 37 male) and 32 healthy control subjects (age, 14.2 +/- 3 years; 15 male) underwent assessment of vascular structure (cIMT and aIMT) and vascular function (flow mediated dilatation [FMD] and glyceryl trinitrate induced dilatation [GTN]). Fasting blood tests were taken to measure levels of hemoglobin A1c, high sensitive C reactive protein, total homocyst(e)ine, serum folate, red cell folate, and lipids.

RESULTS

aIMT, but not cIMT, was significantly greater in the children with type 1 diabetes mellitus than in control subjects (P < .001). In children with type 1 diabetes mellitus, aIMT correlated with glycosylated hemoglobin (r = 0.31, P = .01) and was independently associated with age (beta = 0.38, P = .001) and low-density lipoprotein cholesterol level (beta = 0.38, P = .001). Vascular function (GTN) was worse in children with type 1 diabetes mellitus who had an aIMT >95th percentile, as defined with the control subjects.

CONCLUSIONS

aIMT is an earlier marker than cIMT of preclinical atherosclerosis in children with type 1 diabetes mellitus and relates to known cardiovascular risk factors and metabolic control.

Evaluation of plaque stabilization by fluvastatin with carotid intima- medial elasticity measured by a transcutaneous ultrasonic-based tissue characterization system

AIM

As an approach to tissue characterization, we attempted to classify in vivo carotid plaque tissues in terms of arterial wall elasticity instead of echogenicity on B-mode scanning and investigated whether the effect of fluvastatin on carotid elasticity can be detected in hypercholesterolemic patients.

METHODS

In 170 subjects, simultaneous measurements of intima-media thickness (IMT) and elastic modulus in the circumferential direction (E(theta)) were performed using a new transcutaneous high-resolution Doppler technique.

RESULTS

From the observation of various tissues, an elasticity library was obtained as follows: lipid core, 22+/-15 kPa; calcification, 674+/-384 kPa; lipid core- and calcification-free plaques, 173+/-69 kPa; smooth muscle, 104+/-32 kPa; blood clot, 85+/-68 kPa; fibrosis, 273+/-173 kPa.The effect of fluvastatin (30 mg/day, n=62) was assessed over 12 months using the elasticity distribution and serum markers. The statin reduced low-density lipoprotein cholesterol, high-sensitivity CRP, mean IMT and mean E(theta), and increased nitrite/nitrate. In the max IMT > or =1.1 mm group, both E(theta) and IMT decreased significantly. On the other hand, in the max IMT <1.1 mm group, E(theta) but not IMT decreased significantly. The histogram of the subgroups showing increased E(theta) with max IMT> or =1.1 mm revealed a decrease in areas corresponding to E(theta) of 20200 kPa (lipid/smooth muscle-rich tissue) and an increase in relatively hardened areas of <250 kPa (collagen fibers).

CONCLUSION

Non-invasive echographic carotid arterial elasticity measurement is useful for the classification of atherosclerotic plaques and evaluation of chronological and histopathological changes.

Percentage white: a new feature for ultrasound classification of plaque echogenicity in carotid artery atherosclerosis

Atherosclerotic stenotic and nonstenotic plaques of the carotid artery with low echogenicity have been shown to be associated with cardiovascular disease. The aim was to develop a new method for semiautomated ultrasound image analysis to classify nonstenotic carotid plaques, evaluate cases with multiple plaques and examine the association between a new image analysis feature of echogenicity and predictors of cardiovascular disease. The new image analysis feature, percentage white (PW), represents the fraction of bright structures inside a plaque and is integrated in an objective semiautomated method to evaluate echogenicity (SAMEE) in carotid plaques. PW was constructed to take into account overall echogenicity of the image as well as noise surrounding the plaque. Consecutive ultrasound examinations of carotid plaques from a population-based screening of 64-year-old women with varying risk for cardiovascular disease were selected for the present project; 92 far-wall and 47 near-wall plaques were used as a training dataset to develop the SAMEE algorithm with visual classification according to Gray-Weale as reference; 273 plaques were used to validate the method. All plaques were included in an analysis relating predictors of cardiovascular to average PW in all plaques, PW in the biggest plaque and to the plaque with lowest PW in each subject, respectively. In the training dataset the intermethodological variability between SAMEE and visual classification showed a kappa of 0.78 and a sensitivity and specificity of 96% and 81%, respectively. In the validation set, SAMEE and visual classification showed a kappa of 0.77, a sensitivity of 96% and a specificity of 80%. The reproducibility of PW was high, evidenced by r = 0.96 and CV = 9.85% at repeated examinations. Average PW values were associated with several predictors of cardiovascular risk: lipoprotein (a), HbA1c, blood glucose, apolipoproteinB/apolipoproteinA-I; and associated negatively with the levels of adiponectin and apolipoprotein A-I. In conclusion, PW integrated within a SAMEE is a new feature for assessment of echogenicity in carotid plaques and shows excellent reproducibility and agreement with visual assessment.

Impact of lifestyle-related diseases on carotid arterial wall elasticity as evaluated by an ultrasonic phased-tracking method in Japanese subjects

AIM

We investigated the relationship between coronary risk factors and the intima-media thickness (IMT) and wall elasticity of carotid arteries. A new real-time ultrasonic measurement system that allows measurement of the elasticity of the carotid arterial intima-media complex was applied to 350 subjects, who were also checked for the presence/absence of hypertension, dyslipidemia, diabetes mellitus and regular smoking. Simultaneous measurement of the elastic modulus and IMT was conducted at four sites in the bilateral carotid arteries.

METHODS AND RESULTS

In the group with maximum IMT (max IMT) <1.1 mm, the IMT, as well as the mean elastic modulus in the circumferential direction (Etheta), showed positive correlations with age and coronary risk factors. Multiple regression analysis showed that age, systolic blood pressure and pulse rate remained independent determinants of Etheta. The number of criteria fulfilling the diagnosis of metabolic syndrome showed a good positive correlation with the value of Etheta in the group with max IMT values <1.1 mm.

CONCLUSION

Measurement of carotid arterial wall elasticity together with IMT is useful to detect dis-tortions in intramural elasticity distribution occurring in the early stages of atherosclerosis.

Cardiovascular complications in patients with pheochromocytoma: a mini-review

Phaeochromocytomas are rare neuroendocrine tumours secreting high levels of catecholamines, able to exert serious metabolic and cardiovascular effects. The serious and potentially lethal cardiovascular complications of these tumours are due to the potent effects of secreted catecholamines, especially noradrenaline, the main transmitter released from sympathetic nerve terminals. Hypertension, tachycardia, pallor, headache and anxiety, usually dominate the clinical presentation. Occasionally, patients with predominantly epinephrine-secreting tumours present hypotension or even shock. Other cardiovascular complications of pheochromocytoma include ischaemic heart disease, acute myocardial infarction, cardiac arrhythmias, heart failure due to toxic cardiomyopathy, or pulmonary edema. Catecholamines have been shown to influence the extracellular matrix with collagen deposition and subsequent fibrosis in the arterial wall and in the myocardium. These morphofunctional changes of the myocardium and of arterial wall can be emphasized by ultrasound imaging. Indeed, ultrasound imaging of the myocardium and arterial wall not only identifies wall thickness but also contains information on texture that may be revealed by acoustic tissue characterization. The latter can be quantified through videodensitometric analysis of echographic images or through ultrasonic integrated backscatter signal analysis. This paper reviews cardiovascular complications in patients with pheochromocytoma and utility of the new ultrasound technique as backscatter signal. It is useful for evaluating preclinical pathological morphofunctional changes of the myocardium and arterial wall, characterized by increased collagen content in pheochromocytoma patients. The recognition of early catecholamine-induced alterations in patients with pheochromocytoma, is important to prevent at least morbidity and mortality, before surgical treatment.

Carotid vascular remodelling in patients with autosomal dominant polycystic kidney disease

AIM

To study carotid vascular wall remodelling in patients with autosomal dominant polycystic kidney disease (ADPKD) using integrated backscatter signal (IBS) analysis.

METHODS

Included in the study were: 60 ADPKD patients with preserved renal function, including 32 patient with hypertension and 28 with normotension; 25 patients with essential hypertension; and 30 healthy volunteers. Carotid intima-media thickness (IMT) was measured by 2-D conventional ultrasonography. Acoustic tissue characterization of the carotid wall was assessed by IBS analysis, and the percentage of regions considered as fibromatosis was calculated in all groups.

RESULTS

Carotid IMT in hypertensive ADPKD patients (0.8 +/- 0.05 vs 0.68 +/- 0.02 mm, P < 0.01 and 0.8 +/- 0.05 vs 0.56 +/- 0.04 mm, P < 0.01 respectively) and patients with essential hypertension (0.79 +/- 0.03 vs 0.68 +/- 0.02 mm, P < 0.01 and 0.79 +/- 0.03 vs 0.56 +/- 0.0 4 mm, P < 0.01 respectively) was significantly greater than that of normotensive patients and healthy subjects. Carotid IMT in normotensive ADPKD patients was also significantly greater than that in healthy subjects (0.68 +/- 0.02 vs 0.56 +/- 0.04 mm, P < 0.01). Calibrated IBS (C-IBS) in hypertensive ADPKD patients was significantly greater than that in patients with essential hypertension and normotensive ADPKD patients (-21.2 +/- 1.51 dB vs -23.1 +/- 1.61 dB, P < 0.05; -21.2 +/- 1.51 dB vs -24.5 +/- 1.34 dB, P < 0.01). C-IBS in normotensive ADPKD patients was significantly greater than that in healthy subjects (-24.5 +/- 1.34 dB vs -26.2 +/- 1.69 dB, P < 0.01). The percentage of regions that could be considered as fibromatosis in hypertensive ADPKD patients was significantly greater than that in patients with essential hypertension and normotensive ADPKD patients (30.0% vs 22.4%, P < 0.05; 30.0% vs 17.9%, P < 0.01). The percentage of regions that could be considered as fibromatosis in normotensive ADPKD patients was significantly greater than that in healthy subjects (15.2% vs 10.3%, P < 0.01).

CONCLUSION

Carotid remodelling occurs in the early stage of ADPKD and can be aggravated by hypertension. Fibrosis contributes to the vascular rearrangement.

Association of central obesity with early Carotid intima-media thickening is independent of that from other risk factors

AIM

We investigated whether anthropometric measurements or metabolic risk factors correlated more with vascular changes associated with obesity.

METHODS

One hundred never smoking subjects (71 women, 29 men) without vascular events, with blood pressure (BP) <140/90 mm Hg, LDL cholesterol <4 mmol/l, glucose <6.2 mmol/l participated. Anthropometric measurements (body mass index (BMI), waist/hip ratio (WHR), waist circumference (WC) and Waist/height ratio WHTR) and metabolic risk factors (glucose, insulin, lipid and uric acid levels plus BP) were assessed. Subjects underwent vascular measurements (Carotid intima-media thickness (IMT) using duplex ultrasonography, vascular stiffness assessment (Augmentation Index) by applanation tonometry and brachial artery reactivity tests).

RESULTS

Risk factors were in the 'normal distribution'. BMI, WHR, WC, WHTR correlated significantly with triglyceride, HDL, LDL, insulin, glucose, uric acid and systolic BP levels (P<0.001). IMT correlated with WHTR, BMI, WC, Glucose (P<0.001), Homoeostasis Model Assessment (HOMA) and cholesterol levels (P<0.05). Only Age, WHTR or BMI were significant correlates of IMT in a multivariate analysis (P<0.01) including WHTR or BMI, with age, sex, systolic BP, HDLc and HOMA. Augmentation Index correlated with age (P<0.0001), WHTR and WC (P<0.0005) but with age only in a multivariate analysis. Brachial reactivity did not correlate with any anthropometric or metabolic parameters. Anthropometric cutoff points, (BMI > or =25, WC > or =102 cm men, > or =88 cm women, WHR > or =0.9 men, > or =0.8 women and WHTR > or =0.5 men and women) significantly differentiated normal from abnormal metabolic and vascular measurements. The WHTR ratio > or =0.5 was as reliable as the BMI cutoff > or =25 in determining metabolic and vascular abnormalities. BMI and WHTR were strongly associated with 89% agreement (P<0.0001).

CONCLUSION

These results demonstrated that in 'healthy individuals', anthropometric parameters and metabolic risk factors correlated with each other, but anthropometric parameters were the only significant correlates of carotid IMT. A waist/height ratio > or =0.5 predicts both early vascular and metabolic changes. These data support a risk factor independent vasculotrophic effect of obesity.

Body composition and common carotid artery remodeling in a healthy population

CONTEXT

An independent association between obesity and preclinical carotid atherosclerosis has been demonstrated, however, the pathophysiological links were not clearly established. Body composition (BC) influences systemic hemodynamics and may participate in the remodeling of common carotid artery (CCA), independently of risk factors.

OBJECTIVE

This study evaluated the association between CCA structure and BC in a large population of healthy subjects.

DESIGN

This was a cross-sectional study.

SETTINGS

The study was conducted at 19 European centers.

SUBJECTS

The study included 627 healthy subjects (252 men, age 30-60 yr, body mass index 17-40 kg/m2).

MAIN OUTCOME MEASURES

CCA luminal diameter and intima-media thickness were measured on digitized ultrasound images. Acoustic properties of CCA wall were evaluated by digital densitometric analysis and described in terms of mean gray level. BC was assessed by electrical bioimpedance. Insulin sensitivity (euglycemic hyperinsulinemic clamp) and plasma adiponectin levels were measured. Associations between CCA structure, age, BC, and metabolic and atherosclerotic risk factors were analyzed by multivariate regression models.

RESULTS

Independent factors affecting CCA diameter were fat-free mass and waist girth (standardized r = 0.44 and 0.12; P < 0.01 and < 0.0001; R2 = 0.35); independent correlates of intima-media thickness were age, CCA diameter, systolic blood pressure, and low-density lipoprotein-cholesterol (standardized r = 0.39, 0.25, 0.10, and 0.14; P < 0.005-0.0001; R2 = 0.40). The mean gray level of carotid wall was independently associated with age and waist girth (standardized r = 0.23 and 0.12; P < 0.0001 and = 0.001; R2 = 0.30).

CONCLUSIONS

Findings of this cross-sectional study suggest that BC modulates CCA diameter, and may induce adaptive changes in carotid wall thickness, independently of metabolic and atherosclerotic factors. Central adiposity modifies the acoustic properties of carotid wall.

Statin therapy increases carotid plaque echogenicity in hypercholesterolemic patients

Stabilization of carotid artery plaques by pharmacologic intervention is a promising strategy for the prevention of ischemic stroke. In this study, we examined the effect of 12 months of statin therapy on carotid plaque echogenicity. This study included 81 hypercholesterolemic patients with carotid atherosclerotic plaques. Echogenicity of the largest plaque in each patient was evaluated by ultrasound with integrated backscatter analysis. All patients underwent dietary modification. Forty patients were treated with simvastatin (10 mg/day, n = 24) or atorvastatin (5 mg/day, n = 16) according to the choice by each attending physician. Carotid plaques were monitored by measuring plaque thickness and echogenicity during a 12-month follow-up period. Levels of serum high-sensitivity CRP (hs-CRP), interleukin (IL)-6 and IL-18 were determined in all patients. Total cholesterol, triglyceride, hs-CRP and IL-18 were significantly decreased after 12 months of statin therapy. The change in IL-6 level was not significant. Significant increases in echogenicity of carotid plaques and decreases in plaque thickness were noted after statin therapy. In the 41 patients without statin therapy, carotid plaque echogenicity, plaque thickness and serum levels of inflammatory markers were not significantly altered. Our results suggest that statin therapy in hypercholesterolemic patients for 12 months increases carotid plaque echogenicity and decreases plaque thickness, in addition to lowering serum levels of lipids and inflammatory markers.

Rapid stabilization of vulnerable carotid plaque within 1 month of pitavastatin treatment in patients with acute coronary syndrome

We determined time course of stabilization of echolucent carotid plaques by statin therapy in patients with acute coronary syndrome (ACS). Treatment with 4 mg/d pitavastatin (n = 33) or placebo (n = 32) was initiated within 3 days after onset of ACS in 65 patients with echolucent carotid plaque. Vulnerable carotid plaques were assessed by measuring plaque echolucency using carotid ultrasound with integrated backscatter (IBS) analysis before and 1 month after treatment in all patients. The calibrated IBS value (intima-media IBS value minus adventia IBS) of vulnerable carotid plaques favorably changed at 1 month after treatment in both groups, but the echolucency at 1 month improved more in the pitavastatin than in the placebo group (pitavastatin group: -18.7 +/- 3.3 dB at pretreatment versus -12.7 +/- 2.3 dB at 1 month *P < 0.001; placebo: -19.0 +/- 3.5 dB versus -16.9 +/- 3.2 dB, P < 0.05, *P < 0.01 versus the value at 1 month in placebo group). Levels of CRP, VEGF, and TNFalpha at 1 month were significantly lower in pitavastatin than placebo group. In conclusion, pitavastatin improved carotid plaque echolucency within 1 month of therapy in patients with ACS, in association with decrease in the inflammatory biomarkers related to vulnerable plaques.

Differences in carotid arterial morphology and composition between individuals with and without obstructive coronary artery disease: a cardiovascular magnetic resonance study

OBJECTIVE

We sought to determine differences with cardiovascular magnetic resonance (CMR) in the morphology and composition of the carotid arteries between individuals with angiographically-defined obstructive coronary artery disease (CAD, > or = 50% stenosis, cases) and those with angiographically normal coronaries (no lumen irregularities, controls).

METHODS AND RESULTS

191 participants (50.3% female; 50.8% CAD cases) were imaged with a multi-sequence, carotid CMR protocol at 1.5T. For each segment of the carotid, lumen area, wall area, total vessel area (lumen area + wall area), mean wall thickness and the presence or absence of calcification and lipid-rich necrotic core were recorded bilaterally. In male CAD cases compared to male controls, the distal bulb had a significantly smaller lumen area (60.0 +/- 3.1 vs. 79.7 +/- 3.2 mm2, p < 0.001) and total vessel area (99.6 +/- 4.0 vs. 119.8 +/- 4.1 mm2; p < 0.001), and larger mean wall thickness (1.25 +/- 0.03 vs. 1.11 +/- 0.03 mm; p = 0.002). Similarly, the internal carotid had a smaller lumen area (37.5 +/- 1.8 vs. 44.6 +/- 1.8 mm2; p = 0.006) and smaller total vessel area (64.0 +/- 2.3 vs. 70.9 +/- 2.4 mm2; p = 0.04). These metrics were not significantly different between female groups in the distal bulb and internal carotid or for either gender in the common carotid. Male CAD cases had an increased prevalence of lipid-rich necrotic core (49.0% vs. 19.6%; p = 0.003), while calcification was more prevalent in both male (46.9% vs. 17.4%; p = 0.002) and female (33.3% vs. 14.6%; p = 0.031) CAD cases compared to controls.

CONCLUSION

Males with obstructive CAD compared to male controls had carotid bulbs and internal carotid arteries with smaller total vessel and lumen areas, and an increased prevalence of lipid-rich necrotic core. Carotid calcification was related to CAD status in both males and females. Carotid CMR identifies distinct morphological and compositional differences in the carotid arteries between individuals with and without angiographically-defined obstructive CAD.