Semiautomated and automated algorithms for analysis of the carotid artery wall on computed tomography and sonography: a correlation study.

Objectives—The purpose of this study was to compare automated and semiautomated algorithms for analysis of carotid artery wall thickness and intima-media thickness on multidetector row computed tomographic (CT) angiography and sonography, respectively, and to study the correlation between them. Methods—Twenty consecutive patients underwent multidetector row CT angiographic and sonographic analysis of carotid arteries (mean age, 66 years; age range, 59–79 years). The intima-media thickness of the 40 carotid arteries was measured with novel and dedicated automated software analysis and by 4 observers who manually calculated the intima-media thickness. The carotid artery wall thickness was automatically estimated by using a specific algorithm and was also semiautomatically quantified. The correlation between groups was calculated by using the Pearson ρ statistic, and scatterplots were calculated. We evaluated intermethod agreement using Bland-Altman analysis. Results—By comparing automated carotid artery wall thickness, automated intima-media thickness, semiautomated carotid artery wall thickness, and semiautomated intima-media thickness analyses, a statistically significant association was found, with the highest values obtained for the association between semiautomated and thickness analyses(Pearson ρ = 0.9; 95% confidence interval, 0.82–0.95; P = 0.0001). The lowest values were obtained for the association between semiautomated intima-media thickness and automated carotid artery wall thickness analyses (Pearson ρ = 0.44; 95% confidence interval, 0.15–0.66; P = 0.0047). In the Bland-Altman analysis, the better results were obtained by comparing the semiautomated and automated algorithms for the study of intima-media thickness, with an interval of –16.1% to +43.6%. Conclusions—The results of this preliminary study showed that carotid artery wall thickness and intima-media thickness can be studied with automated software, although the CT analysis needs to be further improved

The Ultrasound Window Into Vascular Ageing: A Technology Review by the VascAgeNet COST Action

Arteriosclerosis; Ultrasound; Vascular ageingArteriosclerosi; Ecografia; Envelliment vascularArteriosclerosis; Ecografía; Envejecimiento vascularNon-invasive ultrasound (US) imaging enables the assessment of the properties of superficial blood vessels. Various modes can be used for vascular characteristics analysis, ranging from radiofrequency (RF) data, Doppler- and standard B/M-mode imaging, to more recent ultra-high frequency and ultrafast techniques. The aim of the present work was to provide an overview of the current state-of-the-art non-invasive US technologies and corresponding vascular ageing characteristics from a technological perspective. Following an introduction about the basic concepts of the US technique, the characteristics considered in this review are clustered into: 1) vessel wall structure; 2) dynamic elastic properties, and 3) reactive vessel properties. The overview shows that ultrasound is a versatile, non-invasive, and safe imaging technique that can be adopted for obtaining information about function, structure, and reactivity in superficial arteries. The most suitable setting for a specific application must be selected according to spatial and temporal resolution requirements. The usefulness of standardization in the validation process and performance metric adoption emerges. Computer-based techniques should always be preferred to manual measures, as long as the algorithms and learning procedures are transparent and well described, and the performance leads to better results. Identification of a minimal clinically important difference is a crucial point for drawing conclusions regarding robustness of the techniques and for the translation into practice of any biomarker.This article is based upon work from COST Action CA18216 VascAgeNet, supported by COST (European Cooperation in Science and Technology, www.cost.eu). A.G. has received funding from “La Caixa” Foundation (LCF/BQ/PR22/11920008). R.E.C is supported by the National Health and Medical Research Council of Australia (reference: 2009005) and by a National Heart Foundation Future Leader Fellowship (reference: 105636). J.A. acknowledges support from the British Heart Foundation [PG/15/104/31913], the Wellcome EPSRC Centre for Medical Engineering at King's College London [WT 203148/Z/16/Z], and the Cardiovascular MedTech Co-operative at Guy's and St Thomas' NHS Foundation Trust [MIC-2016-019]

Appraisal of different ultrasonography indices in patients with carotid artery atherosclerosis

In this study a semi-automated image-processing based method was designed in which the parameters such as intima-media thickness (IMT), resistive index (RI), pulsatility index (PI), dicrotic notch index (DNI), and mean wavelet entropy (MWE) were evaluated in B-mode and Doppler ultrasound in patients presenting with carotid artery atherosclerosis. In a cross-sectional design, 144 men were divided into four groups of control, mild, moderate and severe stenosis subjects. In all individuals, far wall IMT, RI, PI, DNI, and MWE of the left common carotid artery (CCA) were extracted using the proposed method. Our findings showed that the maximum far wall IMT, RI, PI, DNI in the CCA were significantly different in the patients with mild, moderate, and severe stenosis compared to control group (p-value 0.05). The proposed method can help physicians to better identify patients at risk of cardiovascular diseases

Carotid intima-medial thickness measured on multiple ultrasound frames: evaluation of a DICOM-based software system

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The role of vascular biomarkers for primary and secondary prevention. A position paper from the European Society of Cardiology Working Group on peripheral circulation

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CAROTID THREE-DIMENSIONAL ULTRASOUND: LONGITUDINAL MEASUREMENT AND CARDIAC-GATED ACQUISITION

Carotid atherosclerosis is the main cause of stroke - the fourth leading cause of death in Canada - and can be quantified by ultrasound measurements. Intima-media thickness (IMT), total plaque area (TPA) and 3-dimensional ultrasound vessel wall volume (3DUS VWV) were compared in a longitudinal study of 71 patients with diabetic nephropathy randomized to vitamin B or placebo. Only 3DUS VWV was sensitive to a difference in change between treatment groups. We developed and tested cardiac-gated 3DUS acquisition for use in younger subjects with compliant arteries; images were acquired from 400 ms after the start of the cardiac cycle to the beginning of the next cardiac cycle. In healthy volunteers and rheumatoid arthritis patients, change in area over the cardiac cycle was reduced to below that seen in moderate atherosclerosis patients. 3DUS VWV can measure change in atherosclerosis and can now be used in younger patients at risk of atherosclerosis in future studies

Cyclic variation of the common carotid artery structure in relation to prior atherosclerotic burden and physical activity

Background and aims: Cardiovascular disease (CVD) accounts for the most deaths of non-communicable diseases worldwide. It begins with structural and functional changes of the arterial system commonly known as the atherosclerotic process, starting asymptomatically in early childhood, adapting arterial structure and function with advancing age depending on genetic and environmental exposures and finally resulting in CVD events such as myocardial infarction or stroke. CVD risk prediction today is generally based on risk scores, but substantial disadvantages occur since they account only for specific risk factors at one time point. Carotid structure and function (also called carotid stiffness) parameters measured by ultrasound may overcome this disadvantage, since they can provide information on structural and elastic carotid properties and reflect therefore vascular damage accumulated over time. Thus, the aims of this thesis were to summarize the state of the art of ultrasound measurements, to validate the new developed ultrasound analysis system, to assess the variability and reproducibility within the study sample and to investigate the long- and short-term associations of cardiovascular risk factors and carotid stiffness with main focus on physical activity in elderly participants of the SAPALDIA cohort. Methods: The SAPALDIA cohort study is an ongoing multicenter study with a population-based random sample of adults from eight rural and urban areas started in 1991 (SAPALDIA 1), with a first follow-up in 2001-2003 (SAPALDIA 2) and a second follow-up in 2010-2011 (SAPALDIA 3). In SAPALDIA 3, sequential B-mode ultrasound images of the common carotid artery were examined in 3489 participants (51% women) aged between 50-81 years at the time of examination. Expert readers analyzed these ultrasound images with a new analysis system called DYARA (DYnamic ARtery Analysis) according to the state of the art assessed in the review. Thereof, carotid structure parameters were measured and carotid stiffness indices were derived considering blood pressure at time of ultrasound assessment. Validation of the ultrasound analysis program DYARA and reproducibility of carotid parameters were performed in subgroup within the SAPALDIA 3 survey. The presented studies within this thesis comprise cardiovascular risk factor data from the first and second follow-up and therefore, long- and short-term associations with carotid stiffness could be investigated. Results: The intra- and inter-reader results of the validation study were highly consistent with slightly higher bias for analyses with manual interactions compared to the automatic detection. Among the carotid structure parameters, average values across heart cycle showed lower variability than single images in diastole and systole, whereby the relative difference was smaller in lumen diameter values compared to the carotid intima media thickness (CIMT). Based on different statistical approaches, reproducibility values within SAPALDIA 3 were consistently good to excellent for carotid structure and function indices. Findings additionally revealed that subjects itself were the greatest source of variability between two measurements. Multivariate regression analyses suggested that most single cardiovascular risk factors in SAPALDIA 2 were long-termly associated with increased carotid stiffness in SAPALDIA 3 except physical activity and high-density lipoprotein cholesterol (HDL-C). HDL-C was the only protective vascular determinant and no relation was observed for physical activity. Most carotid stiffness parameters were similar strong associated within each cardiovascular risk factor (except compliance showed main deviances among several risk factors). Estimating sex-specific associations of atherosclerotic risk factors and carotid stiffness indicated that increased heart rate was more strongly associated with stiffer arteries across all carotid stiffness parameters in men than in women. Low-density lipoprotein cholesterol (LDL-C) was significantly associated with carotid stiffness only in men and triglyceride only in women. Multifactorial pathway analyses of cardiovascular risk factors in SAPALDIA 3 showed that age was the strongest predictor of carotid stiffness, followed by mean arterial blood pressure and heart rate. Age strongly confounded the association of physical activity and carotid stiffness in multiple regression analyses and therefore, only an univariate association of physical activity and carotid stiffness could be observed. Conclusion: DYARA tackles the challenge of being able to analyze varying ultrasound image qualities with high precision. The high reproducibility and the feasible application in a large sample size suggest that this program can be recommended for epidemiological research, diagnostics and clinical practice. Long- and short-term cardiovascular exposures have added important information to the overall vascular damage assessed by carotid stiffness for both sexes. Although age was the strongest predictor, sex-differences in long-term associations may indicate a certain differentiated susceptibility to cardiovascular risk factors among men and women, which should be investigated in more detail. The presented studies within this thesis provide an important basis towards future investigations targeting the early and late consequences of atherosclerosis, its progression and possible implementations of preventive and/or personalized interventions

Predicting cardiovascular disease morbidity and mortality in chronic kidney disease in Spain. The rationale and design of NEFRONA: a prospective, multicenter, observational cohort study

Background: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). Cardiovascular risk assessment in this population is hampered by the failure of traditional risk factors to fully account for the elevated CVD risk (reverse epidemiology effect) and the presence of emerging risk factors specifically related to kidney failure. Therefore, diagnostic tools capable of improving cardiovascular risk assessment beyond traditional risk factors are currently warranted. We present the protocol of a 4-year prospective study aimed to assess the predictive value of non-invasive imaging techniques and biomarkers for CVD events and mortality in patients with CKD. Methods: From November 2009 to October 2010, 4137 asymptomatic adult patients with stages 2 to 5 CKD will be recruited from nephrology services and dialysis units throughout Spain. During the same period, 843 participants without CKD (control group) will be recruited from lists of primary care physicians, only at baseline. During the follow-up, CVD events and mortality will be recorded from all CKD patients. Clinical and laboratory characteristics will be collected in a medical documentation sheet. Three trained itinerant teams will carry out a carotid ultrasound to assess intima-media thickness and presence of plaques. A composite atherosclerosis score will be constructed based on carotid ultrasound data and measurement of ankle-brachial index. In CKD patients, presence and type of calcifications will be assessed in the wall of carotid, femoral and brachial arteries, and in cardiac valves, by ultrasound. From all participants, blood samples will be collected and stored in a biobank to study novel biomarkers. Conclusions: The NEFRONA study is the first large, prospective study to examine the predictive value of several non-invasive imaging techniques and novel biomarkers in CKD patients throughout Spain. Hereby, we present the protocol of this study aimed to explore the most effective way in which these tests can be integrated with traditional risk factors to maximize CVD detection in this population