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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Molecular imaging can reveal in vivo analysis and quantification of biochemical reactions. To enable cell-surface imaging of receptors, novel ligands have been developed which can be radiolabeled or imaged by bioluminescence. Specific examples include somatostatin receptors, estrogen and progesterone receptors, receptors involved in adhesion and externalization of phosphatidyl serine as an indicator of apoptosis. Central nervous system imaging can be carried out using ligands for receptors including dopamine, serotonin and Gamma amino butyric acid (GABA). In addition, tumor and metabolic imaging can be carried out with the Na-K ATPase pump using the tracer thallium-201 for SPECT or F-18 FDG for PET imaging. Finally, novel receptors or endogenous metabolic pathways can be analyzed combining cell-gene therapy to create specific tracer targets in cells that can be studied by molecular imaging. The challenge of molecular imaging is to first identify key pathways that are unique for a specific disease processes, such as atherosclerosis, cancer, CNS disorders, immunologic and arthritis disorders and next to devise a high-affinity specific small molecular ligand that can be adapted to be a radiolabeled tracer to study this pathway. Advances in genomics and proteomics combine with new peptide-chemistry approaches should provide a large number of targets and tracers in the near future to achieve these imaging objectives.
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PMID:Molecular imaging: new applications for biochemistry. 1255 16

Atherosclerosis is an inflammatory process accumulating numerous inflammatory cells such as macrophages and lymphocytes. This cellular infiltrate has a high metabolic demand, which can be reflected on F-18 FDG positron emission tomographic (PET) imaging. The FDG uptake in atherosclerotic vessels is usually distinguishable as a result of its linear and continuous appearance and mild level of activity. However, occasionally, atherosclerotic plaques present themselves as focal "hot spots," which can be easily misinterpreted as malignancy. This report emphasizes atherosclerotic plaques as a potential pitfall while interpreting FDG scans. It also highlights the importance of radiographic correlation to avoid such an error.
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PMID:F-18 fluorodeoxyglucose uptake in atherosclerotic plaque in the mediastinum mimicking malignancy: another potential for error. 1473 5

Since the discovery of artificially produced radioisotopes in the 1930's, an estimated 10-12 million nuclear medicine diagnostic and therapeutic procedures are currently performed each year only in the United States. Gamma emission imaging has been successfully applied to almost every organ of the body (brain, bone, heart, kidney, lung, neuroreceptors) as well as sites of inflammation, atherosclerosis, and thrombosis. FDG-PET has been used in some of the inflammatory diseases as well. On the other hand, both alpha- and beta-emitting isotopes have been evaluated for brachytherapy of rheumatoid diseases, each with different radiobiological effectiveness. The current status of radionuclides for imaging, therapy and research studies of inflammatory processes is reviewed here and a look into the future directions is described at the conclusion.
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PMID:Application of radioisotopes in inflammation. 1661 Oct 77

Carotid atherosclerosis is a leading cause of cerebrovascular events. The control of cardiovascular risk factors, i.e. tobacco smoking, alcohol abuse, hypertension, dyslipidemia, diabetes and obesity proved to reduce number of fatal and non-fatal strokes but failed to prevent important number of them. Screening for biomarkers in individuals at high risk of symptomatic vascular disease helped to identify some of them. However, as disease is by its nature multifocal, global testing for biomarkers may have limited practical application. New imaging techniques, including direct visualization of artery metabolism, by 18-FDG-PET, has brought new tools to study local atherosclerosis progression and individual plaque metabolic activity. Advances in molecular biology helped to identify inflammatory genes and its strong link to angiogenesis. The later, is thought to play a key role in the transformation to unstable plaque. Studies of the complex role that plays angiogenesis in plaque development will help in future to design effective therapies addressed at the individual cell level. The purpose of the review is to bring new insights into complicated pathophysiology of carotid atherosclerosis.
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PMID:Angiogenesis and inflammation in carotid atherosclerosis. 1850 73

We investigated the ability of fluorodeoxyglucose positron emission tomography (FDG PET) imaging to serially monitor macrophage content in a rabbit model of atherosclerosis. Atherosclerosis was induced in rabbits (n = 8) by a combination of atherogenic diet and balloon denudation of the aorta. At the end of nine months, the rabbits were randomized to a further six months of the same atherogenic diet (progression group) or normal diet (regression group). In vivo uptake of FDG by the thoracic aorta was measured using aortic uptake-to-blood radioactivity ratios at the start and end of the randomized period. A significant increase in FDG uptake of the progression group after continued cholesterol feeding (aortic uptake-to-blood radioactivity: 0.57 +/- 0.02 to 0.68 +/- 0.02, P = 0.001), and a corresponding fall in FDG uptake of the regression group after returning to a normal chow diet (aortic uptake-to-blood radioactivity ratios: 0.67 +/- 0.02 to 0.53 +/- 0.02, P < 0.0001). FDG PET can quantify in vivo macrophage content and serially monitor changes in FDG activity in this rabbit model.
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PMID:In vivo non-invasive serial monitoring of FDG-PET progression and regression in a rabbit model of atherosclerosis. 1903 48

Atherosclerosis is a dynamic inflammatory disorder. The biological composition and inflammatory state of an atherosclerotic plaque, rather than the degree of stenosis or its size are the major determinants of acute clinical events. A noninvasive technique to detect vulnerable atherosclerotic plaque is critically needed. FDG-PET/CT, a combined functional and structural whole-body imaging modality, holds great potential for this purpose. FDG uptake in large arteries has been frequently observed and is associated with cardiovascular risk factors. FDG accumulates in plaque macrophages and uptake is correlated with macrophage density. It is known that vascular FDG uptake and calcification do not overlap significantly and changes of FDG uptake are common, suggesting that FDG uptake may represent a dynamic inflammatory process. It has been reported that vascular FDG uptake can be attenuated by simvastatin in patients, and by the antiinflammatory drug probucol in rabbits. Vascular FDG uptake has been linked to cardiovascular events in some preliminary studies. Data from basic sciences, and animal and clinical studies support the emerging role of FDG-PET/CT in assessing atherosclerosis in large arteries in humans.
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PMID:Emerging role of FDG-PET/CT in assessing atherosclerosis in large arteries. 1898 24

It is not clear if 18FDG-PET can be useful for detection of inflammation in low to moderate carotid stenosis. We studied 15 patients scheduled for endarterectomy with contralateral carotids with less than 50% stenosis. 18-FDG-PET was performed prior to CEA and 3 months following surgery. FDG-uptake values were calculated based on maximum standardized uptake value (SUV) and corresponding uptake ratios. We confirmed by CD68 macrophage staining that FDG accumulation corresponds to active inflammation (R=0.8 p less than 0.005). We found significant correlation between the FDG-uptake in the carotids scheduled for CEA and contralateral carotids with low to moderate stenosis (R=0.9 p less than 0.001). The FDG uptake ratio in the contralateral arteries remained stable on the follow-up imaging (1.15+/-0.2 vs. 1.14+/-0.1, R=0.7 p=0.006). We did not find correlation between FDG uptake and symptomatic or asymptomatic patients, degree of carotid stenosis and vascular risk factors. This is a prospective, preliminary in vivo study demonstrating that low to moderate carotid atherosclerosis can be detected using 18-FDG-PET imaging and highlights the truly systemic nature of atherosclerosis.
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PMID:Imaging of early inflammation in low-to-moderate carotid stenosis by 18-FDG-PET. 1927 79

Our aim was to quantify changes in the inflammatory and calcific components of atherosclerosis in the aortic wall using fluoro-18-2-fluoro-2-deoxy-D-glucose positron emission tomography (18)F-FDGPET and contrast enhanced computerized tomography (CECT) with increasing age. Twelve subjects, 8 men and 4 women aged from 21-80 years who had both (18)F-FDG-PET and CECT of the chest and abdomen were included in this study. Subjects were grouped into three according to age. (18)F-FDG uptake in four segments of the aorta was measured. Using CECT images, aortic segmental wall volumes were measured. Wall calcification volume in each aortic segment was also measured via adaptation of a coronary artery calcium-scoring program to the aorta. Calcification volumes were then subtracted from aortic wall volumes. Each net segmental aortic wall volume was then multiplied by the accompanying mean SUV of the segment to calculate global metabolic activity (GMA) for each aortic segment. Our results showed that in each aortic wall segment, mean SUV, wall volumes, wall calcification volumes, and GMA statistically significantly increased with age. In conclusion, (18)F-FDG uptake, wall volume, wall calcification volume, and GMA in the aorta increase with aging. The (18)F-FDG uptake represents the early inflammatory component of the atherosclerotic process, whereas calcification generally represents a later and irreversible stage of the disease. Measurement and combination of PET and CECT parameters to calculate GMA may allow for optimal morphologic and functional noninvasive quantitative assessment of global aortic atherosclerotic disease.
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PMID:A pilot study of changes in (18)F-FDG uptake, calcification and global metabolic activity of the aorta with aging. 1967 64

[18F]fluorodeoxyglucose positron emission tomography (PET) is a noninvasive metabolic imaging modality that is well-suited to the assessment of activity and extent of large vessel vasculitis. PET imaging has demonstrated its usefulness in diagnosing giant cell arteritis (notably in its silent form), Takayasu's arteritis, and unclassified aortitis. PET imaging could be more effective than magnetic resonance imaging in detecting the earliest stages of vascular wall inflammation. The visual grading of vascular [18F]FDG uptake makes it possible to discriminate arteritis from active atherosclerosis, providing therefore high specificity. High sensitivity can also be achieved provided scanning is performed during active inflammatory phase, preferably before starting corticosteroid treatment. Prospective studies are needed to determine the exact value of PET imaging in assessing other vasculitis subsets, infectious aortitis, and large vessel vasculitis outcome and response to immunosuppressive treatment.
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PMID:[Vasculitis assessment with [18F]FDG positron emission tomography]. 2041 90

Aortitis syndrome is a chronic vasculitis that leads to arterial wall thickening and stiffening in large elastic arteries. However, there are no established markers for assessing arterial stiffening in aortitis syndrome. The cardio-ankle vascular index (CAVI) has recently been utilized to assess arterial stiffening that is associated with atherosclerosis-related diseases. We hypothesized that CAVI can be applicable for assessing alterations in arterial stiffness during immunosuppressive therapy for aortitis syndrome. A 69-year-old woman with a 2-month history of recurrent fever, fatigue, and malaise, showed intense 18F-fluorodeoxyglucose (18F-FDG) uptake in the thoracic aorta and common carotid arteries in 18F-FDG-positron emission tomography. These clinical and imaging findings resulted in the diagnosis of aortitis syndrome. The patient also showed the elevated CAVIs on both sides (right, 10.3; left, 10.4) (normal value for her age, 9.1 +/- 0.8), indicating the arterial stiffness due to aortitis syndrome. The patient was treated for 34 weeks with immunosuppressive therapy, which included oral prednisolone and methotrexate. C-reactive protein (from 4.24 to 0.49 mg/dL) and immunoglobulin G (from 2,627 to 1,524 mg/dL) were decreased by 7 weeks after initiation of the treatment. The decrease in these inflammatory parameters suggests the effectiveness of the immunosuppressive therapy. In addition, after the 34-week treatment, the CAVIs on both sides (right, 9.3; left, 9.2) were within the normal range. These data indicate that the immunosuppressive therapy ameliorates the degree of arterial stiffness. In conclusion, CAVI may be a promising marker for evaluating the effectiveness of immunosuppressive therapy in patients with aortitis syndrome.
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PMID:Cardio-ankle vascular index for evaluating immunosuppressive therapy in a patient with aortitis syndrome. 2082 65


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