Nanoimmunotherapy to treat ischaemic heart disease.

Atherosclerosis is a chronic disease of the large arteries and the underlying cause of myocardial infarction and stroke. Atherosclerosis is driven by cholesterol accumulation and subsequent inflammation in the vessel wall. Despite the clinical successes of lipid-lowering treatments, atherosclerosis remains one of the major threats to human health worldwide.

Multi-Modality Imaging Evaluation of the Whole-Organ Pancreas Transplant.

Pancreas transplants are an important treatment options for patients with severe diabetes mellitus and other medical conditions. Multiple-imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) are available to evaluate the pancreas transplants and their vascular supply, with the graft having a characteristic appearance on each modality. Complications of the graft and its vascular supply present interesting challenges to the clinicians and radiologists caring for this patient population.

Reappraisal of Interpersonal Criticism in Social Anxiety Disorder: A Brain Network Hierarchy Perspective.

Emotion regulation is thought to involve communication between and within large-scale brain networks that underlie emotion reactivity and cognitive control. Aberrant network interaction might therefore be a key neural feature of mental disorders that involve emotion dysregulation. Here we tested whether connectivity hierarchies within and between emotion reactivity and cognitive reappraisal networks distinguishes social anxiety disorder (SAD) patients (n = 70) from healthy controls (HC) (n = 25).

Investigating supramolecular systems using Förster resonance energy transfer.

Supramolecular systems have applications in areas as diverse as materials science, biochemistry, analytical chemistry, and nanomedicine. However, analyzing such systems can be challenging due to the wide range of time scales, binding strengths, distances, and concentrations at which non-covalent phenomena take place. Due to their versatility and sensitivity, Förster resonance energy transfer (FRET)-based techniques are excellently suited to meet such challenges.

Sonophore-enhanced nanoemulsions for optoacoustic imaging of cancer.

Optoacoustic imaging offers the promise of high spatial resolution and, at the same time, penetration depths well beyond the conventional optical imaging technologies, advantages that would be favorable for a variety of clinical applications. However, similar to optical fluorescence imaging, exogenous contrast agents, known as sonophores, need to be developed for molecularly targeted optoacoustic imaging. Despite numerous optoacoustic contrast agents that have been reported, there is a need for more rational design of sonophores.

Diffusion and perfusion MRI quantification in ileal Crohn's disease.

Objectives: To quantify intravoxel incoherent motion (IVIM)-DWI and dynamic contrast-enhanced (DCE)-MRI parameters in normal and abnormal ileal segments in Crohn's disease (CD) patients and to assess the association of these parameters with clinical and MRI-based measurements of CD activity.

Methods: In this prospective study, 27 CD patients (M/F 18/9, mean age 42 years) underwent MR enterography, including IVIM-DWI and DCE-MRI. IVIM-DWI and DCE-MRI parameters were quantified in normal and abnormal small bowel segments, the latter identified by the presence of inflammatory changes.

Hemochromatosis: pathophysiology, evaluation, and management of hepatic iron overload with a focus on MRI.

Hereditary hemochromatosis (HH) is an autosomal recessive disorder that occurs in approximately 1 in 200-250 individuals. Mutations in the HFE gene lead to excess iron absorption. Excess iron in the form of non-transferrin-bound iron (NTBI) causes injury and is readily uptaken by cardiomyocytes, pancreatic islet cells, and hepatocytes.

Quantitative Analysis of Heterogeneous [F]FDG Static (SUV) vs. Patlak (Ki) Whole-body PET Imaging Using Different Segmentation Methods: a Simulation Study.

Purpose: Whole-body (WB) dynamic positron emission tomography (PET) enables imaging of highly quantitative physiological uptake parameters beyond the standardized uptake value (SUV). We present a novel dynamic WB anthropomorphic PET simulation framework to assess the potential of 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG) net uptake rate constant (Ki) imaging in characterizing tumor heterogeneity.

Procedures: Validated heterogeneous [F]FDG tumor kinetics were modeled within the XCAT phantom (ground truth).

Elevated striatal γ-aminobutyric acid in youth with major depressive disorder.

Background: Alterations in γ-aminobutyric acid (GABA) have been hypothesized to play a role in the pathogenesis of psychiatric illness. Our previous work has specifically linked anterior cingulate cortex (ACC) GABA deficits with anhedonia in youth with major depressive disorder (MDD). As anhedonia reflects alterations within the reward circuitry, we sought to extend this investigation and examine GABA levels in another key reward-related region, the striatum, in the same adolescent population.

MASE-sLASER, a short-TE, matched chemical shift displacement error sequence for single-voxel spectroscopy at ultrahigh field.

B inhomogeneity and chemical shift displacement error (CSDE) increase with the main magnetic field strength and are therefore deleterious for magnetic resonance spectroscopy (MRS) at ultrahigh field. A solution is to use adiabatic pulses which operate over a broad range of B and thus are insensitive to B inhomogeneity. Moreover, adiabatic pulses usually have a relatively higher bandwidth, which makes CSDE low to negligible.

Noninvasive prediction of portal pressure with MR elastography and DCE-MRI of the liver and spleen: Preliminary results.

Background: Portal hypertension (PH), defined by hepatic venous pressure gradient (HVPG) ≥5 mmHg and clinically significant PH, defined by HVPG ≥10 mmHg, are complications of chronic liver disease.

Purpose: To assess the diagnostic performance of MR elastography (MRE) and dynamic contrast-enhanced MRI (DCE-MRI) of the liver and spleen for the prediction of PH and clinically significant PH, in comparison with a qualitative PH imaging scoring system.

Study Type: IRB-approved prospective study.

Multi institutional quantitative phantom study of yttrium-90 PET in PET/MRI: the MR-QUEST study.

Background: Yttrium-90 (Y) radioembolization involves the intra-arterial delivery of radioactive microspheres to treat hepatic malignancies. Though this therapy involves careful pre-treatment planning and imaging, little is known about the precise location of the microspheres once they are administered. Recently, there has been growing interest post-radioembolization imaging using positron-emission tomography (PET) for quantitative dosimetry and identifying lesions that may benefit from additional salvage therapy.

New methods to image unstable atherosclerotic plaques.

Atherosclerotic plaque rupture is the primary mechanism responsible for myocardial infarction and stroke, the top two killers worldwide. Despite being potentially fatal, the ubiquitous prevalence of atherosclerosis amongst the middle aged and elderly renders individual events relatively rare. This makes the accurate prediction of MI and stroke challenging.

Reproducibility of myelin content-based human habenula segmentation at 3 Tesla.

In vivo morphological study of the human habenula, a pair of small epithalamic nuclei adjacent to the dorsomedial thalamus, has recently gained significant interest for its role in reward and aversion processing. However, segmenting the habenula from in vivo magnetic resonance imaging (MRI) is challenging due to the habenula's small size and low anatomical contrast. Although manual and semi-automated habenula segmentation methods have been reported, the test-retest reproducibility of the segmented habenula volume and the consistency of the boundaries of habenula segmentation have not been investigated.

Assessment of atherosclerotic plaque activity in patients with sleep apnea using hybrid positron emission tomography/magnetic resonance imaging (PET/MRI): a feasibility study.

Purpose: Evidence suggests that the inflammatory state of an atherosclerotic plaque is important in predicting future risk of plaque rupture. This study aims to investigate the feasibility of measuring plaque inflammation in patients with obstructive sleep apnea (OSA) utilizing advanced vascular imaging - hybrid positron-emission tomography/magnetic resonance imaging (PET/MRI) with fluorodeoxyglucose (FDG) tracer-before and after continuous positive airway pressure (CPAP).

Methods: Patients with newly diagnosed moderate to severe OSA underwent baseline PET/MRI for assessment of vascular inflammation of the carotid arteries and thoracic aorta prior to initiation of CPAP.

Reversible Electroporation-Mediated Liposomal Doxorubicin Delivery to Tumors Can Be Monitored With Zr-Labeled Reporter Nanoparticles.

Reversible electroporation (RE) can facilitate nanoparticle delivery to tumors through direct transfection and from changes in vascular permeability. We investigated a radiolabeled liposomal nanoparticle (Zr-NRep) for monitoring RE-mediated liposomal doxorubicin (DOX) delivery in mouse tumors. Intravenously delivered Zr-NRep allowed positron emission tomography imaging of electroporation-mediated nanoparticle uptake.

Carotid Artery Remodeling Is Segment Specific: An In Vivo Study by Vessel Wall Magnetic Resonance Imaging.

Objective: Early atherosclerosis is often undetected due in part to compensatory enlargement of the outer wall, termed positive remodeling. Variations in hemodynamic conditions and clinical factors influence the patterns of remodeling. The carotid artery provides an opportunity to examine these variations because of the unique geometry of the carotid bulb.

Quantitative Elastography Methods in Liver Disease: Current Evidence and Future Directions.

Chronic liver diseases often result in the development of liver fibrosis and ultimately, cirrhosis. Treatment strategies and prognosis differ greatly depending on the severity of liver fibrosis, thus liver fibrosis staging is clinically relevant. Traditionally, liver biopsy has been the method of choice for fibrosis evaluation.

Frontal and temporal cortical volume, white matter tract integrity, and hemispheric asymmetry in schizotypal personality disorder.

Abnormalities in temporal and frontal cortical volume, white matter tract integrity, and hemispheric asymmetry have been implicated in schizophrenia-spectrum disorders. Schizotypal personality disorder can provide insight into vulnerability and protective factors in these disorders without the confounds associated with chronic psychosis. However, multimodal imaging and asymmetry studies in SPD are sparse.

Combined PET/DCE-MRI in a Rabbit Model of Atherosclerosis: Integrated Quantification of Plaque Inflammation, Permeability, and Burden During Treatment With a Leukotriene A4 Hydrolase Inhibitor.

Objectives: The authors sought to develop combined positron emission tomography (PET) dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to quantify plaque inflammation, permeability, and burden to evaluate the efficacy of a leukotriene A4 hydrolase (LTA4H) inhibitor in a rabbit model of atherosclerosis.

Background: Multimodality PET/MRI allows combining the quantification of atherosclerotic plaque inflammation, neovascularization, permeability, and burden by combined F-fluorodeoxyglucose (F-FDG) PET, DCE-MRI, and morphological MRI. The authors describe a novel, integrated PET-DCE/MRI protocol to noninvasively quantify these parameters in aortic plaques of a rabbit model of atherosclerosis.

Targeting CD40-Induced TRAF6 Signaling in Macrophages Reduces Atherosclerosis.

Background: Disrupting the costimulatory CD40-CD40L dyad reduces atherosclerosis, but can result in immune suppression. The authors recently identified small molecule inhibitors that block the interaction between CD40 and tumor necrosis factor receptor-associated factor (TRAF) 6 (TRAF-STOPs), while leaving CD40-TRAF2/3/5 interactions intact, thereby preserving CD40-mediated immunity.

Objectives: This study evaluates the potential of TRAF-STOP treatment in atherosclerosis.

PET/MR Imaging of Malondialdehyde-Acetaldehyde Epitopes With a Human Antibody Detects Clinically Relevant Atherothrombosis.

Background: Oxidation-specific epitopes (OSEs) are proinflammatory, and elevated levels in plasma predict cardiovascular events.

Objectives: The purpose of this study was to develop novel positron emission tomography (PET) probes to noninvasively image OSE-rich lesions.

Methods: An antigen-binding fragment (Fab) antibody library was constructed from human fetal cord blood.

Improved Evaluation of Antivascular Cancer Therapy Using Constrained Tracer-Kinetic Modeling for Multiagent Dynamic Contrast-Enhanced MRI.

Dynamic contrast-enhanced MRI (DCE-MRI) is a promising technique for assessing the response of tumor vasculature to antivascular therapies. Multiagent DCE-MRI employs a combination of low and high molecular weight contrast agents, which potentially improves the accuracy of estimation of tumor hemodynamic and vascular permeability parameters. In this study, we used multiagent DCE-MRI to assess changes in tumor hemodynamics and vascular permeability after vascular-disrupting therapy.