Contrast-enhanced magnetic resonance imaging for the detection of ruptured coronary plaques in patients with acute myocardial infarction.

Purpose: X-ray coronary angiography (XCA) is the current gold standard for the assessment of lumen encroaching coronary stenosis but XCA does not allow for early detection of rupture-prone vulnerable plaques, which are thought to be the precursor lesions of most acute myocardial infarctions (AMI) and sudden death. The aim of this study was to investigate the potential of delayed contrast-enhanced magnetic resonance coronary vessel wall imaging (CE-MRCVI) for the detection of culprit lesions in the coronary arteries.

Methods: 16 patients (13 male, age 61.

Quantitative diffusion-weighted imaging and dynamic contrast-enhanced characterization of the index lesion with multiparametric MRI in prostate cancer patients.

Purpose: To compare a simplified intravoxel incoherent motion (sIVIM) model to commonly used monoexponential and biexponential models in the characterization of prostate cancer (PCa) and noncancerous prostate tissues, and to investigate combinations of diffusion-weighted imaging (DWI) measures with dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI)-derived parameters in MRI-visible index lesions, to facilitate PCa risk stratification.

Materials And Methods: In this retrospective, Institutional Review Board (IRB)-approved study, 43 consecutive patients with PCa who had 3T MRI exams followed by radical prostatectomy were included. DWI and DCE parameters were measured from one index lesion per patient, and noncancerous central gland and peripheral zone.

Quantitative R2* MRI of the liver with rician noise models for evaluation of hepatic iron overload: Simulation, phantom, and early clinical experience.

Purpose: To compare Rician and non-Rician noise models for quantitative R2 * magnetic resonance imaging (MRI), in a simulation, phantom, and human study.

Materials And Methods: Synthetic 12-echo spoiled GRE (SGRE) datasets were generated with various R2 * rates (0-2000 sec(-1) ) at a signal-to-noise ratio (SNR) of 50, 20, 10, and 5. Phantoms of different MnCl2 concentrations (0-25 mM) were constructed and imaged using a 12-echo 3D SGRE sequence at 1.

Molecular imaging in cardiovascular diseases.

Unlabelled: Cardiovascular diseases remain the leading cause of morbidity and mortality in industrialized and developing countries. In clinical practice, the in-vivo identification of atherosclerotic lesions, which can lead to complications such as heart attack or stroke, remains difficult. Imaging techniques provide the reference standard for the detection of clinically significant atherosclerotic changes in the coronary and carotid arteries.

Molecular imaging in cardiovascular diseases.

Cardiovascular diseases remain the leading cause of morbidity and mortality in industrialized and developing countries. In clinical practice, the in-vivo identification of atherosclerotic lesions, which can lead to complications such as heart attack or stroke, remains difficult. Imaging techniques provide the reference standard for the detection of clinically significant atherosclerotic changes in the coronary and carotid arteries.

2D phase contrast blood flow velocity measurements of the thoracic vasculature: comparison of the effect of gadofosveset trisodium and gadopentetate dimeglumine.

The aim of this prospective study is to compare the performance of 2D time-resolved phase-contrast (PC) MRI prior to and after the administration of an intravascular (gadofosveset-trisodium) and extravascular (gadopentetate-dimeglumine) contrast agent in the same patient in the cardiovascular system. This study was approved by the ethics committee (Study-Number-07/Q0704/2) and registered with the MedicinesAndHealthcareProductsRegulatoryAgency (MHRA-Study-Number-28482/0002/001-0001, EudraCT-Number-2006-007042). All patients signed an informed consent.

In vivo assessment of aortic aneurysm wall integrity using elastin-specific molecular magnetic resonance imaging.

Background: The incidence of abdominal aortic aneurysms (AAAs) has increased during the last decades. However, there is still controversy about the management of medium-sized AAAs. Therefore, novel biomarkers, besides aneurysmal diameter, are needed to assess aortic wall integrity and risk of rupture.

Fibrin-targeted magnetic resonance imaging allows in vivo quantification of thrombus fibrin content and identifies thrombi amenable for thrombolysis.

Objective: Deep venous thrombosis is a major health problem. Thrombolytic therapies are effective in recanalizing the veins and preventing post-thrombotic complications, but there is no consensus on selection criteria. The aim of this study was to investigate a fibrin-specific MRI contrast agent (EP-2104R) for the accurate quantification of thrombus' fibrin content in vivo and for the identification of thrombus suitable for thrombolysis.

Magnetic resonance T1 relaxation time of venous thrombus is determined by iron processing and predicts susceptibility to lysis.

Background: The magnetic resonance longitudinal relaxation time (T1) changes with thrombus age in humans. In this study, we investigate the possible mechanisms that give rise to the T1 signal in venous thrombi and whether changes in T1 relaxation time are informative of the susceptibility to lysis.

Methods And Results: Venous thrombosis was induced in the vena cava of BALB/C mice, and temporal changes in T1 relaxation time correlated with thrombus composition.

Detection and grading of coronary allograft vasculopathy in children with contrast-enhanced magnetic resonance imaging of the coronary vessel wall.

Background: Coronary allograft vasculopathy is the leading cause of late death after heart transplantation in children. It is poorly detected by conventional angiography. Intravascular ultrasound is invasive and costly.

Single breath-hold assessment of cardiac function using an accelerated 3D single breath-hold acquisition technique--comparison of an intravascular and extravascular contrast agent.

Background: Cardiovascular magnetic resonance (CMR) is the current gold standard for the assessment of left ventricular (LV) function. Repeated breath-holds are needed for standard multi-slice 2D cine steady-state free precession sequences (M2D-SSFP). Accelerated single breath-hold techniques suffer from low contrast between blood pool and myocardium.

In vivo assessment of intraplaque and endothelial fibrin in ApoE(-/-) mice by molecular MRI.

Objective: Molecular magnetic resonance imaging (MRI) has emerged as a promising non-invasive modality to characterize atherosclerotic vessel wall changes on a morphological and molecular level. Intraplaque and endothelial fibrin has recently been recognized to play an important role in the progression of atherosclerosis. This study aimed to investigate the feasibility of intraplaque and endothelial fibrin detection using a fibrin-targeted contrast-agent, FTCA (EPIX Pharmaceuticals, Lexington, MA), in a mouse model of atherosclerosis.

Detection of intracoronary thrombus by magnetic resonance imaging in patients with acute myocardial infarction.

Background: Persistent intracoronary thrombus after plaque rupture is associated with an increased risk of subsequent myocardial infarction and mortality. Coronary thrombus is usually visualized invasively by x-ray coronary angiography. Non-contrast-enhanced T1-weighted magnetic resonance (MR) imaging has been useful for direct imaging of carotid thrombus and intraplaque hemorrhage by taking advantage of the short T1 of methemoglobin present in acute thrombus and intraplaque hemorrhage.

Congenital heart disease: cardiovascular MR imaging by using an intravascular blood pool contrast agent.

Purpose: To compare the image quality and diagnostic performance of a contrast agent-specific inversion-recovery (IR) steady-state free precession (SSFP) magnetic resonance (MR) imaging sequence performed by using an intravascular contrast agent (gadofosveset trisodium) with those of a commonly used T2-prepared SSFP sequence performed by using an extravascular (gadopentetate dimeglumine) and an intravascular (gadofosveset trisodium) contrast agent in patients with congenital heart disease (CHD).

Materials And Methods: The local ethics committee and the United Kingdom Medicines and Healthcare products Regulatory Agency approved this study. Patient informed consent was obtained.

Noninvasive assessment of atherosclerotic plaque progression in ApoE-/- mice using susceptibility gradient mapping.

Background: Macrophages have been identified as a major contributor to plaque development and destabilization in atherosclerosis. The aim of this study was to noninvasively assess uptake of citrate coated very small iron oxide particles at different stages of plaque development in the brachiocephalic artery of apoE(-/-) mice. Susceptibility gradient mapping (SGM) was applied to generate positive contrast images and to quantify iron oxide uptake.

Assessment of atherosclerotic plaque burden with an elastin-specific magnetic resonance contrast agent.

Atherosclerosis and its consequences remain the main cause of mortality in industrialized and developing nations. Plaque burden and progression have been shown to be independent predictors for future cardiac events by intravascular ultrasound. Routine prospective imaging is hampered by the invasive nature of intravascular ultrasound.

Molecular imaging with targeted contrast agents.

Molecular imaging with targeted contrast agents by magnetic resonance imaging (MRI) allows for the noninvasive detection and characterization of biological changes on a molecular level. In this article, the principles of molecular MRI and its applications in cardiovascular diseases are reviewed. First, basic properties of positive and negative contrast agents are introduced and their effect on signal generation in a magnetic field is described.

High spatial resolution and high contrast visualization of brain arteries and veins: impact of blood pool contrast agent and water-selective excitation imaging at 3T.

Purpose: To investigate a blood pool contrast agent and water-selective excitation imaging at 3 T for high spatial and high contrast imaging of brain vessels including the veins.

Methods And Results: 48 clinical patients (47 ± 18 years old) were included. Based on clinical findings, twenty-four patients received a single dose of standard extracellular Gadoterate-meglumine (Dotarem®) and 24 received the blood pool contrast agent Gadofosveset (Vasovist®).

[MR imaging of lymph nodes using Gadofluorine M: feasibility in a swine model at 1.5 and 3T].

Purpose: To investigate the potential of Gadofluorine M for targeted lymph node imaging in a human size animal model and on a clinical MR scanner at 1.5 and 3 T.

Materials And Methods: Pelvic and cervical lymph nodes in a swine model were investigated prior to and 24 hours after intravenous administration of 50 micromol/kg body weight Gadofluorine M, an experimental contrast agent.

Gadofosveset-enhanced magnetic resonance imaging of human carotid atherosclerotic plaques: a proof-of-concept study.

Objective: To investigate the potential of gadofosveset-enhanced MR imaging for the characterization of human carotid atherosclerotic plaques.

Materials And Methods: Sixteen (9 symptomatic, 7 asymptomatic) patients with 70% to 99% carotid stenosis (according to NASCET criteria) were included (13 men, 3 women, mean age 67.6 years).

Cardiovascular MRI in small animals.

Imaging studies of cardiovascular disease in small rodents have become a prerequisite in preclinical cardiovascular research. Transgenic and gene-knockout models of cardiovascular diseases enables the investigation of the influence of single genes or groups of genes on disease pathogenesis. In addition, experimental and genetically altered models provide valuable in vivo platforms to investigate the efficacy of novel drugs and contrast agents.

Thrombus imaging with fibrin-specific gadolinium-based MR contrast agent EP-2104R: results of a phase II clinical study of feasibility.

Purpose: To determine the feasibility of detecting thrombi using a fibrin-specific gadolinium-based magnetic resonance imaging contrast agent, EP-2104R.

Methods: Subjects with confirmed thrombus in the venous system (n = 14), or in the heart, or arterial system (n = 38) were enrolled. Patients were imaged before and at various times following a 4 mumol/kg intravenous bolus injection of EP-2104R: <1 hour (N = 16), 2 to 6 hours (N = 36), and/or 20 to 36 hours (N = 33).

A novel fluorescent imaging agent for diffuse optical tomography of the breast: first clinical experience in patients.

Purpose: This is the first clinical evaluation of a novel fluorescent imaging agent (Omocianine) for breast cancer detection with diffuse optical tomography (DOT).

Procedures: Eleven women suspected of breast cancer were imaged with DOT at multiple time points (up to 24 h) after receiving an intravenous injection of Omocianine (doses 0.01 to 0.

High spatial resolution magnetic resonance imaging of experimental cerebral venous thrombosis with a blood pool contrast agent.

Purpose: The purpose of this study was to investigate the feasibility of clot visualization in small sinus and cortical veins with contrast enhanced MRA in a cerebral venous thrombosis animal model using a blood pool contrast agent, Gadofosveset, and high spatial resolution imaging.

Material And Methods: For induction of cerebral venous thrombosis a recently developed combined interventional and microsurgical model was used. Cerebral sinus and cortical vein thrombosis was induced in six pigs.

Molecular magnetic resonance imaging of myocardial perfusion with EP-3600, a collagen-specific contrast agent: initial feasibility study in a swine model.

Background: Cardiac magnetic resonance (MR) perfusion imaging during the first pass after intravenous administration of extracellular contrast agents is hampered by the spatial and temporal resolution achievable and by the artifacts seen in ultrafast MR imaging. Furthermore, time-consuming quantitative data analysis is often added. The use of molecular MR imaging with a target-specific contrast agent with perfusion-dependent binding to myocardium may enable prolonged visualization of perfusion defects and thus may help to overcome limitations of currently used first-pass extracellular MR imaging.