Comparison of gated and non-gated fast multislice black-blood carotid imaging using rapid extended coverage and inflow/outflow saturation techniques.

Purpose: To comparatively analyze two fast in vivo multislice black-blood carotid artery vessel wall imaging techniques with and without cardiac gating.

Materials And Methods: Eight subjects with carotid artery atherosclerosis, and four healthy subjects were studied using two black-blood multislice techniques: rapid extended coverage double inversion recovery (REX-DIR), and inflow/outflow saturation band (IOSB) rapid acquisition with relaxation enhancement (RARE) multislice acquisitions. Quantitative, qualitative, and morphometric analyses were performed on images.

Atherothrombosis and high-risk plaque: Part II: approaches by noninvasive computed tomographic/magnetic resonance imaging.

This second part of the review on atherothrombosis highlights the diffuse nature of the disease analyzing the feasibility and potential of the noninvasive imaging modalities, including computed tomography (electron-beam computed and multi-detector computed tomography) and magnetic resonance imaging for its detection and monitoring. These imaging modalities are being established as promising tools in high-risk cardiovascular patients for identification and/or management of coronary calcification, stenotic or obstructive disease, high-risk plaques (not necessarily stenotic), and overall burden of the disease. In addition, such technology facilitates the understanding of the processes involved in the development and progression of atherothrombosis responsible for coronary, cerebral, and peripheral ischemic events.

Atherothrombosis and high-risk plaque: part I: evolving concepts.

Atherothrombosis is a complex disease in which cholesterol deposition, inflammation, and thrombus formation play a major role. Rupture of high-risk, vulnerable plaques is responsible for coronary thrombosis, the main cause of unstable angina, acute myocardial infarction, and sudden cardiac death. In addition to rupture, plaque erosion may also lead to occlusive thrombosis and acute coronary events.

Chronic thrombus detection with in vivo magnetic resonance imaging and a fibrin-targeted contrast agent.

Background: Arterial thrombosis plays a critical role in acute coronary syndromes and stroke. Therefore, the ability to detect thrombus in vivo has a significant clinical implication. Magnetic resonance imaging (MRI) has shown promise in noninvasive thrombus detection.

Fibrin-targeted contrast agent for improvement of in vivo acute thrombus detection with magnetic resonance imaging.

Objective: Plaque rupture leading to thrombosis and occlusion is a major source of acute coronary syndromes. Methods for accurate detection of thrombosis in veins or arteries may expand our capacity to predict clinical complications and guide therapeutic decisions. We sought to demonstrate the feasibility of in vivo acute thrombus detection using a fibrin-targeted gadolinium based magnetic resonance contrast agent (EP-1242).

Effects of aggressive versus conventional lipid-lowering therapy by simvastatin on human atherosclerotic lesions: a prospective, randomized, double-blind trial with high-resolution magnetic resonance imaging.

Objectives: This study sought to compare the effects of aggressive and conventional lipid lowering by two different dosages of the same statin on early human atherosclerotic lesions using serial noninvasive magnetic resonance imaging (MRI).

Background: Regression of atherosclerotic lesions by lipid-lowering therapy has been reported.

Methods: Using a double-blind design, newly diagnosed hypercholesterolemic patients (n = 51) with asymptomatic aortic and/or carotid atherosclerotic plaques were randomized to 20 mg/day (n = 29) or 80 mg/day (n = 22) simvastatin.

Risk scores predict atherosclerotic lesions in young people.

Background: Atherosclerosis begins in childhood and progresses through young adulthood to form the lesions that cause coronary heart disease. These preclinical lesions are associated with coronary heart disease risk factors in young persons.

Methods: The Pathobiological Determinants of Atherosclerosis in Youth study collected arteries and samples of blood and other tissues from persons aged 15 to 34 years who died of external causes and underwent autopsy in forensic laboratories.

Tracking atherosclerosis regression: a clinical tool in preventive cardiology.

Progression of coronary artery disease was initially evaluated using quantitative coronary angiography with ensuing evidence indicating a strong relationship to adverse cardiovascular outcomes. Since then, several other atherosclerosis imaging techniques have emerged as new tools in cardiovascular medicine to evaluate the effectiveness of preventive therapies through serial monitoring of changes in atherosclerosis burden. Conducting large randomized trials to test new approaches for the medical management of atherosclerosis, with the goal of showing a reduction in event rates, may often be impractical in an era of cost containment and reduced societal resources.

Assessment of myocardial perfusion and viability from routine contrast-enhanced 16-detector-row computed tomography of the heart: preliminary results.

To assess the diagnostic accuracy of 16-detector-row computed tomography (16DCT) of the heart in the assessment of myocardial perfusion and viability in comparison to stress perfusion magnetic resonance imaging (SP-MRI) and delayed-enhancement magnetic resonance imaging (DE-MRI). A number of 30 patients underwent both 16DCT and MRI of the heart. Contrast-enhanced 16DCT data sets were reviewed for areas of myocardium with reduced attenuation.

Does shear stress modulate both plaque progression and regression in the thoracic aorta? Human study using serial magnetic resonance imaging.

Objectives: The purpose of this study was to investigate the role of shear stress (SS) in plaque regression.

Background: A condition favorable to the development of atherosclerotic lesions is low oscillating SS. In the descending thoracic aorta, the relationship between plaque distribution and SS has never been characterized.

Effect of lipid-lowering therapy with atorvastatin on atherosclerotic aortic plaques detected by noninvasive magnetic resonance imaging.

Objectives: We sought to elucidate the effects of 20-mg versus 5-mg atorvastatin on thoracic and abdominal aortic plaques.

Background: Regression of thoracic aortic plaques by simvastatin was demonstrated using magnetic resonance imaging (MRI). However, the effects of different doses of statin have not been assessed.

Recombinant HDL-like nanoparticles: a specific contrast agent for MRI of atherosclerotic plaques.

A new contrast agent for MRI based on recombinant HDL-like nanoparticles has been prepared. It shows a great potential as a contrast agent for atherosclerotic plaques in a relative short time (24 h post-injection) as it is selective for the plaques and is an endogenous molecule. It also can distinguish between different types of plaques as the enhancement obtained is different, depending on plaque composition.

Optimization of ex vivo CT- and MR- imaging of atherosclerotic vessel wall changes.

Objective: To optimize a methodology for ex vivo imaging of atherosclerotic vessel wall changes using multidetector-row computed tomography (MDCT) and multi-contrast magnetic resonance imaging (MRI).

Methods: In phantom studies and studies on intact ex vivo porcine and human hearts, various filling mixtures of MDCT and MRI contrast agents have been evaluated, to enable filling and distension of the coronary arteries for optimal visualization of atherosclerotic vessel wall changes with both techniques. Various proportions of methyl cellulose, iodine-containing CT contrast agent and paramagnetic MR contrast agent containing iron-oxide particles have been tested.

Molecular, cellular and functional imaging of atherothrombosis.

Recent years have seen a dramatic expansion in our knowledge of the events of atherogenesis and in the availability of drugs that can retard the progression - and even induce the regression - of this disease process. Our understanding has been advanced considerably by developments in genetics and molecular biology and by the use of genetically modified mouse models that have provided key mechanistic insights. Increasingly sophisticated imaging techniques will capitalize on these advances by bringing forward diagnosis, enhancing disease characterization and providing more precise evaluation of the effects of treatment.

In vivo 16-slice, multidetector-row computed tomography for the assessment of experimental atherosclerosis: comparison with magnetic resonance imaging and histopathology.

Background: Noninvasive imaging can detect early atherosclerotic disease. Magnetic resonance imaging (MRI), because of its excellent spatial resolution, is already established as a tool for plaque characterization. Sixteen-slice, multidetector-row computed tomography (MDCT) was recently introduced into the field of cardiac imaging, with promising results for noninvasive angiography.

Quantification of human atherosclerotic plaques using spatially enhanced cluster analysis of multicontrast-weighted magnetic resonance images.

One of the current limitations of magnetic resonance imaging (MRI) is the lack of an objective method to classify plaque components. Here we present a cluster analysis technique that can objectively quantify and classify MR images of atherosclerotic plaques. We obtained three-dimensional (3D) images from 12 human coronary artery specimens on a 9.

Serial studies of mouse atherosclerosis by in vivo magnetic resonance imaging detect lesion regression after correction of dyslipidemia.

Objective: We determined the effects of sustained normocholesterolemia on advanced mouse atherosclerosis and whether changes in plaque size and composition can be detected noninvasively by MRI.

Methods And Results: Aortic arch segments containing advanced lesions from apolipoprotein E-deficient (apoE-/-) mice (total cholesterol 1281+/-97 mg/dL) were transplanted into syngeneic wild-type (WT; 111+/-11 mg/dL) or apoE-/- (702+/-74 mg/dL) recipient mice on chow diet. Mice underwent serial MRI at 3, 5, 7, and 9 weeks after transplantation.

Molecular imaging for the diagnosis of high-risk plaque.

Despite advances in our understanding of the pathogenesis of atherosclerosis and new therapeutic modalities, the absence of an adequate method for early detection limits the prevention and treatment of the disease. High-resolution magnetic resonance has recently emerged as one of the most promising techniques for the non-invasive study of atherothrombotic disease, as it can characterize plaque composition and monitor progression. This review of plaque imaging focuses on the most recent technique: "molecular imaging", which uses specific contrast agents targeted to plaque components, and may allow for better stratification of "high-risk" plaque and "high-risk" patients.

Rapid extended coverage simultaneous multisection black-blood vessel wall MR imaging.

A two-dimensional rapid extended coverage (REX) rapid acquisition with relaxation enhancement (RARE) pulse sequence for simultaneous multisection double inversion-recovery (DIR) black-blood vessel wall magnetic resonance (MR) imaging was developed. Aortic vessel wall MR imaging was performed in five healthy subjects (mean age, 33 years +/- 4 [SD]) and five patients with atherosclerotic disease (mean age, 67 years +/- 11.7).

In vivo magnetic resonance evaluation of associations between aortic atherosclerosis and both risk factors and coronary artery disease in patients referred for coronary angiography.

Background: Magnetic resonance imaging was recently reported to detect atherosclerotic plaques in thoracic and abdominal aortas.

Methods: Using magnetic resonance imaging, we investigated associations of risk factors and plasma inflammatory markers with plaques in both thoracic and abdominal aortas in 102 patients undergoing coronary angiography. Associations between coronary artery disease (CAD) and aortic plaques were also evaluated.

Lipid-rich atherosclerotic plaques detected by gadofluorine-enhanced in vivo magnetic resonance imaging.

Background: MRI of specific components in atherosclerotic plaque may provide information on plaque stability and its potential to rupture. We evaluated gadofluorine in atherosclerotic rabbits using a new MR sequence that allows plaque detection within 1 hour after injection and assessed enhancement in lipid-rich and non-lipid-rich plaques.

Methods And Results: Twelve rabbits with aortic plaque and 6 controls underwent MRI before and up to 24 hours after gadofluorine injection (50 micromol/kg).

Atherosclerotic plaque characterization by MR imaging.

The MR imaging of carotid artery and aortic plaque has undergone significant improvement in the last decade. Early studies utilizing ex vivo specimens and spin echo or fast spin echo imaging, led to the conclusion that T2-weighting was the best single contrast to characterize carotid plaque morphology. On these images, the fibrous plaque appears bright and the lipid core is dark; thrombus can have variable intensity.

Multidetector-row computed tomography and magnetic resonance imaging of atherosclerotic lesions in human ex vivo coronary arteries.

In the present study, we tested the ability of multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI) to identify and retrospectively characterize atherosclerotic lesions in human ex vivo coronary arteries. Thirteen ex vivo hearts were studied with MDCT and MRI. MDCT-images were obtained with an isotropic voxel size of 0.

Magnetic resonance imaging and computed tomography in assessment of atherosclerotic plaque.

The two most promising noninvasive imaging modalities for the study of atherosclerosis are magnetic resonance imaging (MRI) and computed tomography (CT). Both have been shown to be capable of imaging vessel wall structures and differentiating various stages of atherosclerotic wall changes. MRI has been applied in various in vivo human studies to image atherosclerotic plaques in coronary arteries, carotid arteries, and aorta.

Parallel and nonparallel simultaneous multislice black-blood double inversion recovery techniques for vessel wall imaging.

Purpose: To reduce long examination times of black-blood vessel wall imaging by acquiring multiple slices simultaneously and by using parallel acquisition techniques.

Materials And Methods: DIR-rapid acquisition with relaxation enhancement (RARE) techniques imaging up to 10 simultaneous slices per acquisition with single and multiple 180 degrees -reinversion pulses were developed. A slab-selective reinversion multislice DIR-RARE sequence incorporating generalized autocalibrating partially parallel acquisitions (GRAPPA) imaging was implemented.