Development of a nomogram model for predicting acute stroke events based on dual-energy CTA analysis of carotid intraplaque and perivascular adipose tissue

Objective

To evaluate the predictive value of dual-energy CT angiography (DECTA) parameters of carotid intraplaque and perivascular adipose tissue (PVAT) in acute stroke events.

Methods

A retrospective analysis was conducted using clinical, laboratory, and imaging data from patients who underwent dual-energy carotid CTA and cranial MRI. Acute cerebral infarctions occurring in the ipsilateral anterior circulation were classified as the symptomatic group (STA group), while other cases were categorized as the asymptomatic group (ATA group). LASSO regression was employed to identify key predictors. These predictors were used to develop three models: the intraplaque model (IP_Model), the perivascular adipose tissue model (PA_Model), and the nomogram model (Nomo_Model). The predictive accuracy of the models was evaluated using receiver operating characteristic (ROC) analysis, calibration curves, and decision curve analysis. Statistical significance was defined as p < 0.05.

Results

Seventy-five patients (mean age: 68.7 ± 8.7 years) were analyzed. LASSO regression identified seven significant variables (IP_Zeff, IP_40KH, IP_K, PA_FF, PA_VNC, PA_Rho, PA_K) for model construction. The Nomo_Model demonstrated superior predictive performance compared to the IP_Model and PA_Model, achieving an area under the curve (AUC) of 0.962, with a sensitivity of 95.8%, specificity of 82.4%, precision of 82.6%, an F1 score of 0.809, and an accuracy of 88.0%. The clinical decision curve analysis further validated the Nomo_Model's significant clinical utility.

Conclusion

DECTA imaging parameters revealed significant differences in carotid intraplaque and PVAT characteristics between the STA and ATA groups. Integrating these parameters into the nomogram (Nomo_Model) resulted in a highly accurate and clinically relevant tool for predicting acute stroke risk.

High-resolution magnetic resonance vessel wall imaging in ischemic stroke and carotid artery atherosclerotic stenosis: A review

Ischemic stroke is a significant burden on human health worldwide. Carotid Atherosclerosis stenosis plays an important role in the comprehensive assessment and prevention of ischemic stroke patients. High-resolution vessel wall magnetic resonance imaging has emerged as a successful technique for assessing carotid atherosclerosis stenosis. This advanced imaging modality has shown promise in effectively displaying a wide range of characteristics associated with the condition, leading to a comprehensive evaluation. High-resolution vessel wall magnetic resonance imaging not only enables a comprehensive evaluation of the instability of carotid atherosclerosis stenosis plaques but also provides valuable information for understanding the pathogenesis and predicting the prognosis of ischemic stroke patients. The purpose of this article is to review the application of high-resolution magnetic resonance imaging in ischemic stroke and carotid atherosclerotic stenosis.

Vascular Aging and Atherosclerosis: A Perspective on Aging

Vascular aging (VA) is recognized as a pivotal factor in the development and progression of atherosclerosis (AS). Although various epidemiological and clinical research has demonstrated an intimate connection between aging and AS, the candidate mechanisms still require thorough examination. This review adopts an aging-centric perspective to deepen the comprehension of the intricate relationship between biological aging, vascular cell senescence, and AS. Various aging-related physiological factors influence the physical system's reactions, including oxygen radicals, inflammation, lipids, angiotensin II, mechanical forces, glucose levels, and insulin resistance. These factors cause endothelial dysfunction, barrier damage, sclerosis, and inflammation for VA and promote AS via distinct or shared pathways. Furthermore, the increase of senescent cells inside the vascular tissues, caused by genetic damage, dysregulation, secretome changes, and epigenetic modifications, might be the primary cause of VA.

Quantitative measurement of atheroma burden: reproducibility in serial studies of atherosclerotic femoral arteries

OBJECTIVES

This study aims to evaluate the reproducibility of measures of plaque morphology in serially acquired black-blood MRI of untreated atherosclerotic femoral arteries.

MATERIALS AND METHODS

MR studies was obtained from 42 timepoints, on 12 patients with known femoral artery atherosclerosis. Images with a 3D isotropic FLASH with DANTE-prepared black blood contrast (DASH) at a 3-T scanner were acquired at baseline, within 1 week, and at 1 month. Six of the patients were scanned additionally at 6 months. Inter-scan and inter-observer variations of arterial area/volume measurements were evaluated.

RESULTS

Measurement of vessel area, lumen area, wall area and wall volume showed inter-scan intraclass correlation coefficients (ICC) ranging from 0.92 to 0.97 for 3 scans, 0.91-0.97 for 4 scans, and inter-observer ICCs of 0.89-0.96. Among 3 scans, the coefficients of variance (CV) for the vessel area, lumen area, wall area and wall volume were 4.1%, 6.5%, 7.5%, and 4.4%. CVs among 4 scans ranged from 4.4% to 7.9%, and interobserver CVs ranged from 6.1% to 11.8% for the different area/volume measurements.

CONCLUSION

DASH MRI is useful for quantifying atherosclerotic vessel area and volume of femoral arteries with low variability among serial repeated scans and between observers.

Characteristics of atheromatosis in the prediabetes stage: a cross-sectional investigation of the ILERVAS project

Background

Prediabetes has recently been associated with subclinical atheromatous disease in the middle-aged population. Our aim was to characterize atheromatous plaque burden by the number of affected territories and the total plaque area in the prediabetes stage.

Methods

Atheromatous plaque burden (quantity of plaques and total plaque area) was assessed in 12 territories from the carotid and femoral regions using ultrasonography in 6688 non-diabetic middle-aged subjects without cardiovascular disease. Prediabetes was defined by glycosylated hemoglobin (HbA1c) between 5.7 and 6.4% according to the American Diabetes Association guidelines.

Results

Prediabetes was diagnosed in 33.9% (n = 2269) of the ILERVAS participants. Subjects with prediabetes presented a higher prevalence of subclinical atheromatous disease than participants with HbA1c < 5.7% (70.4 vs. 67.5%, p = 0.017). In the population with prediabetes this was observed at the level of the carotid territory (p < 0.001), but not in the femoral arteries. Participants in the prediabetes stage also presented a significantly higher number of affected territories (2 [1;3] vs. 1 [0;3], p = 0.002), with a positive correlation between HbA1c levels and the number of affected territories (r = 0.068, p < 0.001). However, atheromatosis was only significantly (p = 0.016) magnified by prediabetes in those subjects with 3 or more cardiovascular risk factors. The multivariable logistic regression model showed that the well-established cardiovascular risk factors together with HbA1c were independently associated with the presence of atheromatous disease in participants with prediabetes. When males and females were analyzed separately, we found that only men with prediabetes presented both carotid and femoral atherosclerosis, as well as an increase of total plaque area in comparison with non-prediabetic subjects.

Conclusions

The prediabetes stage is accompanied by an increased subclinical atheromatous disease only in the presence of other cardiovascular risk factors. Prediabetes modulates the atherogenic effect of cardiovascular risk factors in terms of distribution and total plaque area in a sex-dependent manner.

Trial registration NCT03228459 (clinicaltrials.gov)

Intracranial artery stenosis magnetic resonance imaging aetiology and progression study: Rationale and design

BACKGROUND

It has been shown that intracranial artery stenosis (ICAS) plays a key role in Chinese ischemic stroke or transient ischemic attack (TIA) patients. Many vascular diseases can lead to ICAS, such as atherosclerosis, dissection, vasculitis, moyamoya disease, and reversible cerebral vasoconstriction syndrome (RCVS). In addition, progression of intracranial atherosclerotic disease (ICAD) will increase the risk of ischemic cerebrovascular events. The ICASMAP study primarily aims to determine the etiology and disease distribution of ICAS using noninvasive magnetic resonance (MR) imaging and evaluate the rate for progression of ICAD in symptomatic population.

METHODS

The ICASMAP study is a prospective, observational, and multicenter study by recruiting 300 subjects (18-80 years old) with recent stroke or TIA (within 2 weeks after onset of symptoms) in China. All the subjects will undergo MR imaging examination including brain and intracranial artery MR imaging at baseline. In addition, the clinical risk factors will be collected and blood biomarkers will be tested. A subgroup of more than 200 subjects who were diagnosed with ICAD according to baseline MR imaging will be followed up for 2 years. During the follow-up study, MR imaging examination will be performed at 12 and 24 months. The primary end point is presence of progression of intracranial artery atherosclerotic plaques.

CONCLUSIONS

The ICASMAP study investigates the etiology of ICAS and progression of ICAD in Chinese stroke patients and may help to improve the precise diagnosis and intervention of ICAS and stroke prevention.

Negative Carotid Artery Remodeling in Early Type 2 Diabetes Mellitus and Increased Carotid Plaque Vulnerability in Obesity as Assessed by Magnetic Resonance Imaging

Background Ischemic stroke from carotid plaque embolism remains a major cause of morbidity in patients with type 2 diabetes mellitus (T2 DM ). However, the effect of early T2 DM and obesity on carotid remodeling and plaque burden remains elusive. We assessed carotid remodeling and plaque composition by carotid magnetic resonance imaging in patients with short-duration T2 DM compared with a sex- and age-matched control group. Methods and Results One hundred patients with T2 DM (duration <5 years) and 100 sex- and age-matched controls underwent bilateral carotid artery magnetic resonance imaging in a 1.5-T magnetic resonance imaging scanner. Plaque burden was quantified by normalized wall index, maximum wall thickness, maximum wall area, and minimum lumen size. Plaque morphology was quantified by calcified plaque volume, necrotic core volume, and loose matrix volume. Magnetic resonance imaging data were available for 149 and 177 carotid arteries from T2 DM patients and controls, respectively. Adjusted for age and sex, T2 DM was associated with increased plaque burden indicated by a higher normalized wall index (ratio 1.03 [95% confidence interval, 1.002; 1.06], P=0.03), and negative remodeling indicated by a lower minimum lumen area (ratio 0.81 [0.74; 0.89], P<0.001), and lower maximum wall area (ratio 0.94 [0.88; 1.00], P=0.048) compared with controls. In both T2 DM and controls, body mass index ≥30.0 kg/m2 was associated with an 80% increase in total calcified plaque volume, and a 44% increase in necrotic core volume compared with body mass index <25.0 kg/m2. Conclusions Short-duration T2 DM was associated with increased carotid plaque burden and negative remodeling. Obesity was associated with increased carotid artery necrotic core volume and calcification independently of diabetes mellitus status. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 00674271.

The Growing Field of Imaging of Atherosclerosis in Peripheral Arteries

In the past decades, peripheral arteries have represented a model for the comprehension of atherosclerosis as well as for the development of new diagnostic imaging modalities and therapeutic strategies. Peripheral arteries may represent a window to study atherosclerosis. Pathology has prominently contributed to move the clinical and research attention from the arterial lumen stenosis and angiography to morphological and functional imaging techniques. Evidence from large and prospective cohort or randomized controlled studies is still modest. Nevertheless, several emerging imaging investigations represent a potential tool for a comprehensive "in vivo" evaluation of the entire natural history of peripheral atherosclerosis. This constitutes a demanding assignment, as it would be desirable to obtain both single-lesion focused and extensive arterial system views to achieve the most accurate prognostic information. Our narrative review rests upon the fundamental pathological evidence, summarizing the rapidly growing field of imaging of atherosclerosis in peripheral arteries and presenting a selection of both currently available and emerging imaging techniques.

Combination of Magnetic Resonance Angiography and Computational Fluid Dynamics May Predict the Risk of Stroke in Patients with Asymptomatic Carotid Plaques

Background

Atherosclerosis plaques in the carotid arteries frequently have been found in patients with stroke. However, the pathogenesis of carotid plaque from asymptomatic to cerebrovascular events is a complex process which is still not completely understood. We aimed to investigate the prognosis of asymptomatic carotid atherosclerotic plaques by use of magnetic resonance angiography (MRA) combined with computational fluid dynamics (CFD).

Material/Methods

We prospectively studied a cohort of 228 participants (mean age 59.21±8.48) with asymptomatic carotid atherosclerotic plaques; mean follow-up duration was 1147.56±224.84 days. Plaque morphology parameters were obtained by MRA analysis. Lumen area (LA) and total vessel area (TVA) were measured, and wall area (WA=TVA−LA) and normalized wall area index (NWI=WA/TVA) were calculated. CFD analysis was performed to evaluate hemodynamic characteristics, including wall pressure (WP) and wall shear stress (WSS). Independent risk factors for stroke were obtained by Cox regression analysis. The area under the curve (AUC) of receiver operator characteristic (ROC) and Z-statistic test were used to evaluate risk factors.

Results

Logistics regression analysis showed NWI (OR: 3.472, 95% CI: 2.943–4.096, P=0.11) and WSS (OR: 6.974, 95% CI: 1.070–45.453, P=0.42) were independent risk factors of stroke for patients with asymptomatic carotid plaques. The area under the ROC curve values for WSS, NWI, and WSS+NWI were 0.772, 0.798, and 0.903, respectively.

Conclusions

The combination of plaque morphology characteristics NWI and hemodynamic parameter WSS may predict the risk of stroke in patients with asymptomatic carotid plaques.

Vessel wall differences between middle cerebral artery and basilar artery plaques on magnetic resonance imaging

A recent study showed that posterior circulation plaques have a greater capacity for positive remodeling in a non-Asian population. We aimed to investigate if the features of plaques in the middle cerebral artery (MCA) were different from those in the basilar artery (BA) in a northern Chinese population. We retrospectively analysed the records of 71 consecutive patients with acute ischemic stroke. All patients had at least one MCA or BA plaque with early or mild (<50% stenosis) atherosclerosis identified using vessel wall magnetic resonance imaging. The remodeling ratio, eccentricity index, and plaque range were compared between MCA and BA plaques using multilevel analysis. A total of 101 plaques were included. There were 70 plaques located in the MCA and 31 plaques located in the BA. The features of non-advanced atherosclerotic plaques did not differ between the MCA and BA when accounting for the degree of stenosis or plaque burden in a northern Chinese population. Symptomatic plaques were associated with a higher eccentricity index and smaller plaque range than asymptomatic plaques under the same plaque burden. Further studies are warranted to investigate the progression of atherosclerosis in different intracranial arteries.

Determinants of carotid atherosclerotic plaque burden in a stroke-free population

BACKGROUND AND AIMS

In a large stroke-free population, we sought to identify cardiovascular risk factors and carotid plaque components associated with carotid plaque burden, lumen volume and stenosis.

METHODS

The carotid arteries of 1562 stroke-free participants from The Rotterdam Study were imaged on a 1.5-Tesla MRI scanner. Inner and outer wall of the carotid arteries were automatically segmented and lumen volume (mm³), wall volume (outer wall-inner wall) and plaque burden (wall volume/outer wall volume) (%) were quantified. Plaque components were visually determined and luminal stenosis was assessed. We analyzed associations of cardiovascular risk factors and carotid plaque components with plaque burden and lumen volumes using regression analysis.

RESULTS

We investigated 2821 carotid plaques and found that women had larger plaque burden (50.7 ± 7.8% vs. 49.2 ± 7.7%, p < 0.0001) and smaller lumen volumes (933 ± 286 mm³vs. 1078 ± 334 mm³, p < 0.0001) than men. In women, age, HDL-cholesterol and systolic blood pressure, and in men, total cholesterol, non-HDL cholesterol and statin use were independently associated with higher plaque burden and lumen volume. Furthermore, smoking and diabetes were associated with lumen volume in men (respectively p = 0.04 and p = 0.002). Intraplaque hemorrhage (IPH) and lipid were related to a larger plaque burden (OR 1.30 [1.05-1.60] and OR 1.28[1.06-1.55]). Finally, within the highest quartile of plaque burden, IPH was strongly associated with luminal stenosis independent of age, sex, plaque burden and composition (Beta = 15.2; [11.8-18.6]).

CONCLUSIONS

Several cardiovascular risk factors and plaque components, in particular IPH, are associated with higher plaque burden. Carotid IPH is strongly associated with an increased luminal stenosis.

Expansive arterial remodeling of the carotid arteries and its effect on atherosclerotic plaque composition and vulnerability: an in-vivo black-blood 3T CMR study in symptomatic stroke patients

BACKGROUND

Based on intravascular ultrasound of the coronary arteries expansive arterial remodeling is supposed to be a feature of the vulnerable atheroslerotic plaque. However, till now little is known regarding the clinical impact of expansive remodeling of carotid lesions. Therefore, we sought to evaluate the correlation of expansive arterial remodeling of the carotid arteries with atherosclerotic plaque composition and vulnerability using in-vivo Cardiovascular Magnetic Resonance (CMR).

METHODS

One hundred eleven symptomatic patients (74 male/71.8 ± 10.3y) with acute unilateral ischemic stroke and carotid plaques of at least 2 mm thickness were included. All patients received a dedicated multi-sequence black-blood carotid CMR (3Tesla) of the proximal internal carotid arteries (ICA). Measurements of lumen, wall, outer wall, hemorrhage, calcification and necrotic core were determined. Each vessel-segment was classified according to American Heart Association (AHA) criteria for vulnerable plaque. A modified remodeling index (mRI) was established by dividing the average outer vessel area of the ICA segments by the lumen area measured on TOF images in a not affected reference segment at the distal ipsilateral ICA. Correlations of mRI and clinical symptoms as well as plaque morphology/vessel dimensions were evaluated.

RESULTS

Seventy-eight percent (157/202) of all internal carotid arteries showed atherosclerotic disease with AHA Lesion-Type (LT) III or higher. The mRI of the ICA was significantly different in normal artery segments (AHA LT I; mRI 1.9) compared to atherosclerotic segments (AHA LT III-VII; mRI 2.5; p < 0.0001). Between AHA LT III-VII there was no significant difference of mRI. Significant correlations (p < 0.05) of the mRI with lumen-area (LA), wall-area (WA), vessel-area (VA) and wall-thickness (WT), necrotic-core area (NC), and ulcer-area were observed. With respect to clinical presentation (symptomatic/asymptomatic side) and luminal narrowing (stenotic/non-stenotic) no relevant correlations or significant differences regarding the mRI were found.

CONCLUSION

Expansive arterial remodeling exists in the ICA. However, no significant association between expansive arterial remodeling, stroke symptoms, complicated AHA VI plaque, and luminal stenosis could be established. Hence, results of our study suggest that expansive arterial remodeling is not a very practical marker for plaque vulnerability in the carotid arteries.

Joint segmentation of lumen and outer wall from femoral artery MR images: Towards 3D imaging measurements of peripheral arterial disease

Three-dimensional (3D) measurements of peripheral arterial disease (PAD) plaque burden extracted from fast black-blood magnetic resonance (MR) images have shown to be more predictive of clinical outcomes than PAD stenosis measurements. To this end, accurate segmentation of the femoral artery lumen and outer wall is required for generating volumetric measurements of PAD plaque burden. Here, we propose a semi-automated algorithm to jointly segment the femoral artery lumen and outer wall surfaces from 3D black-blood MR images, which are reoriented and reconstructed along the medial axis of the femoral artery to obtain improved spatial coherence between slices of the long, thin femoral artery and to reduce computation time. The developed segmentation algorithm enforces two priors in a global optimization manner: the spatial consistency between the adjacent 2D slices and the anatomical region order between the femoral artery lumen and outer wall surfaces. The formulated combinatorial optimization problem for segmentation is solved globally and exactly by means of convex relaxation using a coupled continuous max-flow (CCMF) model, which is a dual formulation to the convex relaxed optimization problem. In addition, the CCMF model directly derives an efficient duality-based algorithm based on the modern multiplier augmented optimization scheme, which has been implemented on a GPU for fast computation. The computed segmentations from the developed algorithm were compared to manual delineations from experts using 20 black-blood MR images. The developed algorithm yielded both high accuracy (Dice similarity coefficients ≥ 87% for both the lumen and outer wall surfaces) and high reproducibility (intra-class correlation coefficient of 0.95 for generating vessel wall area), while outperforming the state-of-the-art method in terms of computational time by a factor of ≈ 20.

Intra-individual comparison of carotid and femoral atherosclerotic plaque features with in vivo MR plaque imaging

The purpose of this study was to evaluate differences of plaque composition and morphology within the same patient in different vascular beds using non-invasive MR-plaque imaging. 28 patients (67.8 ± 7.4 years, 8 females) with high Framingham general cardiovascular disease 10-year risk score and mild-to-moderate atherosclerosis were consecutively included in the study. All subjects underwent a dedicated MRI-plaque imaging protocol using TOF and T1w and T2w black-blood-sequences with fat suppression at 1.5 T. The scan was centered on the carotid bulb of the carotid arteries and on the most stenotic lesion of the ipsilateral femoral artery, respectively. Plaques were classified according to the American Heart Association (AHA) lesion type classification and area measurements of lumen, wall and the major plaque components, such as calcification, necrotic core and hemorrhage were determined in consensus by two blinded reviewers using dedicated software (Cascade, Seattle, USA). Plaque components were recorded as maximum percentages of the wall area. Carotid arteries had larger maximum wall and smaller minimum lumen areas (p < 0.001) than femoral arteries, whereas no significant difference was find with respect to the max. NWI (p = 0.87). Prevalence of lipid-rich AHA lesion type IV/V and complicated AHA lesion type VI with hemorrhage/thrombus/fibrous cap rupture was significantly higher in the carotid arteries compared to the femoral arteries. Plaque composition as percentage of the vessel wall differed significantly between carotid and femoral arteries: Max. %necrotic core and max. %hemorrhage were significantly higher in the carotid arteries compared to the femoral arteries (p = 0.001 and p = 0.02, respectively). Max. %calcification did not differ significantly. Average stenotic degree of carotid arteries at duplex was 49.7 ± 12.5 (%). Non-invasive MR plaque-imaging is able to visualize differences in plaque composition across the vascular tree. We observed significant differences in quantitative and qualitative plaque features between carotid and femoral arteries within the same patient, which in the future could help to improve risk stratification in patients with atherosclerosis.

The Additive Value of Femoral Ultrasound for Subclinical Atherosclerosis Assessment in a Single Center Cohort of 962 Adults, Including High Risk Patients with Rheumatoid Arthritis, Human Immunodeficiency Virus Infection and Type 2 Diabetes Mellitus

BACKGROUND

Presence of femoral atheromatic plaques, an emerging cardiovascular disease (CVD) biomarker additional to carotid plaques, is poorly investigated in conditions associating with accelerated atherosclerosis such as Rheumatoid Arthritis (RA), Human Immunodeficiency Virus (HIV) infection and Type 2 Diabetes Mellitus (T2DM).

OBJECTIVE/METHODS

To assess the frequency of femoral/carotid subclinical atheromatosis phenotypes in RA, HIV and T2DM and search for each disease-specific probability of either femoral and/or carotid subclinical atheromatosis, we examined by ultrasound a single-center cohort of CVD-free individuals comprised of consecutive non-diabetic patients with RA (n=226) and HIV (n=133), T2DM patients (n=109) and non-diabetic individuals with suspected/known hypertension (n=494) who served as reference group.

RESULTS

Subclinical atheromatosis--defined as local plaque presence in at least on arterial bed--was diagnosed in 50% of the overall population. Among them, femoral plaques only were found in 25% of either RA or HIV patients, as well as in 16% of T2DM patients and 35% of reference subjects. After adjusting for all classical CVD risk factors, RA and HIV patients had comparable probability to reference group of having femoral plaques, but higher probability (1.75; 1.17-2.63 (odds ratio; 95% confidence intervals), 2.04; 1.14-3.64, respectively) of having carotid plaques, whereas T2DM patients had higher probability to have femoral and carotid plaques, albeit, due to their pronounced dyslipidemic profile.

CONCLUSION

RA and HIV accelerate predominantly carotid than femoral. A "two windows" carotid/femoral, rather than carotid alone ultrasound, screening improves substantially subclinical atheromatosis detection in patients at high CVD risk.

Non-coronary atherosclerosis

During the last decades, the clinical and research interest in atherosclerosis has been mostly focused on coronary arteries. After the publications of the European Society Guidelines and AHA/ACC Guidelines on Peripheral artery diseases, and of the Registry REduction in Atherothrombosis for Continued Health Registry, there has been an increased interest in atherosclerosis of the lower extremity arteries and its presence in multifocal disease. However, awareness in the general population and the medical community of non-coronary artery diseases, and of its major prognostic implications remain relatively low. The aim of this general review stemming out of an ESC Working Group on Peripheral Circulation meeting in 2011 is to enhance awareness of this complex disease highlighting the importance of the involvement of atherosclerosis at different levels with respect to clinical presentation, diagnosis, and co-existence of the disease in the distinct arterial territories. We also emphasize the need of an interdisciplinary approach to face the broad and complex spectrum of multifocal disease, and try to propose a series of tentative recommendations and measures to be implemented in non-coronary atherosclerosis.

Combined application of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging in early diagnosis of vulnerable carotid atherosclerotic plaques

Objective

To assess the correlations between atherosclerotic plaque characteristics and inflammatory activity by combined use of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI).

Methods

Patients underwent 18F-FDG PET/CT and MRI. Target/background ratios (TBR) of axial sections were determined from mean standard uptake values (SUV). Correlations between TBR and mean vessel wall thickness, total vessel area, lumen area, vessel wall area and normalized wall index were calculated. Plaque types were defined as calcified, collagen, lipid or haemorrhage. Plaques were also classified as thick, thin, or ruptured fibrous cap.

Results

The study included 31 patients (1178 plaque slices). There was a significant decrease in TBR values across the fibrous cap groups, such that ruptured > thin > thick. Lipid and haemorrhage plaques had significantly higher TBR than calcification and collagen plaques. There were weak positive correlations between TBR and mean vessel wall thickness, vessel wall area and normalized wall index.

Conclusions

Thin or ruptured plaques, lipid-rich plaques and haemorrhagic plaques possess high inflammatory activity. The combination of 18F-FDG PET/CT and MRI could be useful for qualitative and quantitative diagnosis of carotid atherosclerotic plaques.

SELF-SUPERVISED MRI TISSUE SEGMENTATION BY DISCRIMINATIVE CLUSTERING

The study of brain lesions can benefit from a clear identification of transitions between healthy and pathological tissues, through the analysis of brain imaging data. Current signal processing methods, able to address these issues, often rely on strong prior information. In this article, a new method for tissue segmentation is proposed. It is based on a discriminative strategy, in a self-supervised machine learning approach. This method avoids the use of prior information, which makes it very versatile, and able to cope with different tissue types. It also returns tissue probabilities for each voxel, crucial for a good characterization of the evolution of brain lesions. Simulated as well as real benchmark data were used to validate the accuracy of the method and compare it against other segmentation algorithms.

MRI in Lower Extremity Peripheral Arterial Disease: Recent Advancements

Evaluation of peripheral arterial disease by cardiovascular magnetic resonance imaging continues to develop. Of the clinical diagnostics tests currently available, magnetic resonance angiography is well established as one of the preferred techniques for determining areas of arterial occlusive disease affecting the lower extremities. Despite this, there have been new developments in non-gadolinium based contrast-enhanced studies as well as testing done at higher field strength scanners. In the research arena, magnetic resonance spectroscopy, calf muscle perfusion imaging and atherosclerotic plaque evaluation all have made significant advancements over the last year. These techniques are gaining traction as surrogate endpoints in clinical trials of novel therapeutics aimed at alleviating symptoms in patients with peripheral arterial disease.

Low levels of IgM antibodies to oxidized cardiolipin increase and high levels decrease risk of cardiovascular disease among 60-year olds: a prospective study

Background

Antibodies against cardiolipin (aCL) are associated with increased risk of cardiovascular disease (CVD). We here determine the role of antibodies against oxidized CL (aOxCL).

Methods

One third of sixty-year olds from the Stockholm County were screened (2039 men, 2193 women), where 211 incident CVD-cases and 633 age- and sex-matched controls were identified (5–7 year follow-up). Antibodies were determined by ELISA and uptake of oxLDL in macrophages by FACScan.

Results

IgM aOxCL was lower among CVD cases than controls (p=0.024). aOxCL-levels were divided in quartiles with the highest quartile set as the reference group. After adjustment for smoking, BMI, type II diabetes, hypercholesterolaemia and hypertension, an increased risk was determined in the lowest quartile of IgM aOxCL (OR: 1.80, CI: 1.12–2.91, p=0.0159); OR for men in the lowest quartile was 2.46 (CI 1.34–4.53, p=0.0037) for CVD and for stroke: 12.28 (CI: 1.48-101.77, p=0.02). IgG aOxCL levels did not differ between quartiles in CVD-risk. High levels of IgM aOxCL (reaching significance above 86th) and IgG aOxCL (above 95th percentile) were associated with decreased risk of CVD (OR: 0.485, CI: 0.283-0.829; p=0.0082 and OR: 0.23, CI: 0.07-0.69; p=0.0091). aCL were not associated with CVD. oxCL but not CL competed out uptake of OxLDL in macrophages, and aOxLDL recognized oxCL but not CL. In contrast to aCL, aOxCL was not dependent on co-factor Beta2-glycoprotein-I.

Conclusions

aOxCL is a novel risk/protection marker for CVD, with therapeutic implications. OxCL competes with oxLDL for uptake in macrophages and the possibility that aOxCL inhibits such uptake by interfering with same or similar epitopes in oxCL and oxLDL should be further studied.

Subclinical femoral atheromatosis in rheumatoid arthritis: comparable prevalence to diabetes mellitus in a case-control study

OBJECTIVE

Rheumatoid arthritis (RA) is associated with increased coronary artery disease (CAD) and subclinical carotid atheromatosis, reportedly to equal diabetes mellitus (DM). The presence of atheromatic plaques in femoral arteries of RA patients without DM was compared with with DM patients.

METHODS

Femoral plaques were recorded in 30 (17 men, age 43.0±12 years, disease duration 9.9±7.1 years) and 60 older RA patients (27 men, age 63.0±7.1 years, disease duration 11.4±7.9 years) matched 1:1 for age, gender and disease duration with DM types 1 and 2 patients, respectively. All were asymptomatic and free of CAD.

RESULTS

The number of femoral plaques per patient in either RA subgroup was comparable with DM (0.64±0.82 vs 0.77±0.89 in total respective populations, p=0.340); percentages of patients with femoral plaques were also comparable (RA vs DM type 1 20% and 13%, respectively; RA vs DM type 2 58% and 66%, respectively). Hypertension and dyslipidaemia were significantly more frequent in both DM groups than RA groups.

CONCLUSIONS

Subclinical femoral atheromatosis in RA is analogous to DM, further confirming the territorial unrestricted acceleration of the atheromatic process in these patients. Cardiovascular risk stratification based on both carotid and femoral plaque detection in RA should be addressed prospectively.

Environmentally persistent free radicals decrease cardiac function and increase pulmonary artery pressure

Epidemiological studies have consistently linked inhalation of particulate matter (PM) to increased cardiac morbidity and mortality, especially in at risk populations. However, few studies have examined the effect of PM on baseline cardiac function in otherwise healthy individuals. In addition, airborne PM contain environmentally persistent free radicals (EPFR) capable of redox cycling in biological systems. The purpose of this study was to determine whether nose-only inhalation of EPFRs (20 min/day for 7 days) could decrease baseline left ventricular function in healthy male Sprague-Dawley rats. The model EPFR tested was 1,2-dichlorobenzene chemisorbed to 0.2-μm-diameter silica/CuO particles at 230°C (DCB230). Inhalation of vehicle or silica particles served as controls. Twenty-four hours after the last exposure, rats were anesthetized (isoflurane) and ventilated (3 l/min), and left ventricular function was assessed using pressure-volume catheters. Compared with controls, inhalation of DCB230 significantly decreased baseline stroke volume, cardiac output, and stroke work. End-diastolic volume and end-diastolic pressure were also significantly reduced; however, ventricular contractility and relaxation were not changed. DCB230 also significantly increased pulmonary arterial pressure and produced hyperplasia in small pulmonary arteries. Plasma levels of C-reactive protein were significantly increased by exposure to DCB230, as were levels of heme oxygenase-1 and SOD2 in the left ventricle. Together, these data show that inhalation of EPFRs, but not silica particles, decreases baseline cardiac function in healthy rats by decreasing cardiac filling, secondary to increased pulmonary resistance. These EPFRs also produced systemic inflammation and increased oxidative stress markers in the left ventricle.