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68Ga-DOTA chelate, a novel imaging agent for assessment of myocardial perfusion and infarction detection in a rodent model
<p>Background<br />Magnetic resonance imaging (MRI) with Gadolinium 1,4,7,10-tetraazacyclododecane-N′,N″,N′′′,N″″-tetraacetic acid (Gd-DOTA) enables assessment of myocardial perfusion during first-pass of the contrast ...
Assessment of myocardial viability with [15O]water PET: A validation study in experimental myocardial infarction
<p>Background: Assessment of myocardial viability is often needed in patients with chest pain and reduced ejection fraction. We evaluated the performance of reduced resting MBF, perfusable tissue fraction (PTF), and ...
Imaging of αvβ3 integrin expression in experimental myocardial ischemia with [68Ga]NODAGA-RGD positron emission tomography
<p>BACKGROUND: </p><p>Radiolabeled RGD peptides detect αvβ3 integrin expression associated with angiogenesis and extracellular matrix remodeling after myocardial infarction. We studied whether cardiac positron emission ...
Folate Receptor β Targeted PET Imaging of Macrophages in Autoimmune Myocarditis
<p>Rationale: Currently available imaging techniques have limited specificity for the detection of active myocardial inflammation. Aluminum fluoride-18-labeled 1,4,7-triazacyclononane-N,N′,N″-triacetic acid conjugated folate (18F-FOL) is a positron emission tomography (PET) tracer targeting folate receptor β (FR-β) that is expressed on activated macrophages at sites of inflammation. We evaluated 18F-FOL PET for the detection of myocardial inflammation in rats with autoimmune myocarditis and studied expression of FR-β in human cardiac sarcoidosis specimens. </p><p>Methods: Myocarditis was induced by immunizing rats (n = 18) with porcine cardiac myosin in complete Freund’s adjuvant. Control rats (n = 6) were injected with Freund’s adjuvant alone. 18F-FOL was intravenously injected followed by imaging with a small animal PET/computed tomography (CT) scanner and autoradiography. Contrast-enhanced high-resolution CT or 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG) PET images were used for co-registration. Rat tissue sections and myocardial autopsy samples of 6 patients with cardiac sarcoidosis were studied for macrophages and FR-β. </p><p>Results: The myocardium of 10 out of 18 immunized rats showed focal macrophage-rich inflammatory lesions with FR-β expression occurring mainly in M1-polarized macrophages. PET images showed focal myocardial 18F-FOL uptake co-localizing with inflammatory lesions (SUVmean, 2.1 ± 1.1), whereas uptake in the remote myocardium of immunized rats and controls was low (SUVmean, 0.4 ± 0.2 and 0.4 ± 0.1, respectively; P < 0.01). Ex vivo autoradiography of tissue sections confirmed uptake of 18F-FOL in myocardial inflammatory lesions. Uptake of 18F-FOL to inflamed myocardium was efficiently blocked by a non-labeled FR-β ligand folate glucosamine in vivo. The myocardium of patients with cardiac sarcoidosis showed many FR-β-positive macrophages in inflammatory lesions. Conclusion: In a rat model of autoimmune myocarditis, 18F-FOL shows specific uptake in inflamed myocardium containing macrophages expressing FR-β, which were also present in human cardiac sarcoid lesions. Imaging of FR-β expression is a potential approach for the detection of active myocardial inflammation.<br /></p>...
Measurement of brown adipose tissue mass using a novel dual-echo magnetic resonance imaging approach: A validation study
Objective<br />The aim of this study was to evaluate and validate magnetic resonance imaging (MRI) for the visualization and quantification of brown adipose tissue (BAT) in vivo in a rat model. We hypothesized that, based ...
Glucagon-like peptide-1 receptor expression after myocardial infarction: Imaging study using [68Ga]NODAGA-exendin-4 positron emission tomography
<h3>BACKGROUND: </h3><div><p>Activation of glucagon-like peptide-1 receptor (GLP-1R) signaling protects against cardiac dysfunction and remodeling after myocardial infarction (MI). The aim of the study was to evaluate ...
Two weeks of moderate-intensity continuous training, but not high-intensity interval training, increases insulin-stimulated intestinal glucose uptake
<p>Similar to muscles, the intestine is also insulin resistant in obese subjects and subjects with impaired glucose tolerance. Exercise training improves muscle insulin sensitivity, but its effects on intestinal metabolism ...