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| 3. |
- Valastyán, Iván, et al.
(författare)
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Data acquisition and image reconstruction systems from the MiniPET scanners to the CARDIOTOM camera
- 2007
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Ingår i: Nuclear Physics Methods And Accelerators In Biology And Medicine. - : American Institute of Physics (AIP). - 9780735404724 ; , s. 282-283
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Bokkapitel (refereegranskat)abstract
- Nuclear imaging devices play an important role in medical diagnosis as well as drug research. The first and second generation data acquisition systems and the image reconstruction library developed provide a unified hardware and software platform for the miniPET-I, miniPET-II small animal PET scanners and for the CARDIOTOM(TM).
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| 4. |
- Valastyán, Iván, et al.
(författare)
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Validation of an iterative reconstruction for a mobile tomographic gamma camera system - The Cardiotom
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 580:2, s. 1097-1100
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Tidskriftsartikel (refereegranskat)abstract
- The Cardiotom is a mobile gamma camera that uses ectomography, an alternative method of acquisition to SPECT. It is designed for early diagnosis of myocardial and cerebral infarctions in the emergency room. Ectomography is a limited view angle method, using a rotating slant hole collimator and a stationary camera head, to acquire projection images. The aim of this work was to validate a fully 3D ML-EM iterative reconstruction algorithm for the Cardiotom. Validation measurements were performed with Tc-99m point sources. Resolution in the reconstructed volume was determined in X, Y. and Z directions from the point spread functions. The results were compared with the values for the formerly used filtered back projection (FBP). The new reconstruction algorithm provides greatly improved depth resolution with respect to the FBP method previously implemented on the Cardiotom. Furthermore, for clinical examinations, images can be available for interpretation within 15 min of the injection, therefore, valuable information can be obtained without delaying treatment of the patient. (c) 2007 Elsevier B.V. All rights reserved.
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| 5. |
- Ahmed, M., et al.
(författare)
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Molecular Imaging of a New Multimodal Microbubble for Adhesion Molecule Targeting
- 2019
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Ingår i: Cellular and Molecular Bioengineering. - : Springer Science and Business Media LLC. - 1865-5025 .- 1865-5033. ; 12:1, s. 15-32
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionInflammation is an important risk-associated component of many diseases and can be diagnosed by molecular imaging of specific molecules. The aim of this study was to evaluate the possibility of targeting adhesion molecules on inflammation-activated endothelial cells and macrophages using an innovative multimodal polyvinyl alcohol-based microbubble (MB) contrast agent developed for diagnostic use in ultrasound, magnetic resonance, and nuclear imaging.MethodsWe assessed the binding efficiency of antibody-conjugated multimodal contrast to inflamed murine or human endothelial cells (ECs), and to peritoneal macrophages isolated from rats with peritonitis, utilizing the fluorescence characteristics of the MBs. Single-photon emission tomography (SPECT) was used to illustrate Tc-99m-labeled MB targeting and distribution in an experimental in vivo model of inflammation.ResultsFlow cytometry and confocal microscopy showed that binding of antibody-targeted MBs to the adhesion molecules ICAM-1, VCAM-1, or E-selectin, expressed on cytokine-stimulated ECs, was up to sixfold higher for human and 12-fold higher for mouse ECs, compared with that of non-targeted MBs. Under flow conditions, both VCAM-1- and E-selectin-targeted MBs adhered more firmly to stimulated human ECs than to untreated cells, while VCAM-1-targeted MBs adhered best to stimulated murine ECs. SPECT imaging showed an approximate doubling of signal intensity from the abdomen of rats with peritonitis, compared with healthy controls, after injection of anti-ICAM-1-MBs.ConclusionsThis novel multilayer contrast agent can specifically target adhesion molecules expressed as a result of inflammatory stimuli in vitro, and has potential for use in disease-specific multimodal diagnostics in vivo using antibodies against targets of interest.
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| 6. |
- Ahmed, M., et al.
(författare)
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Molecular Imaging of Inflammation in a Mouse Model of Atherosclerosis Using a Zirconium-89-Labeled Probe
- 2020
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Ingår i: International Journal of Nanomedicine. - 1178-2013. ; 15, s. 6137-6152
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Tidskriftsartikel (refereegranskat)abstract
- Background: Beyond clinical atherosclerosis imaging of vessel stenosis and plaque morphology, early detection of inflamed atherosclerotic lesions by molecular imaging could improve risk assessment and clinical management in high-risk patients. To identify inflamed atherosclerotic lesions by molecular imaging in vivo, we studied the specificity of our radiotracer based on maleylated (Mal) human serum albumin (HSA), which targets key features of unstable atherosclerotic lesions. Materials and Methods: Mal-HSA was radiolabeled with a positron-emitting metal ion, zirconium-89 (Zr-89(4+)). The targeting potential of this probe was compared with unspecific Zr-89-HSA and F-18-FDG in an experimental model of atherosclerosis (Apoe(-/-) mice, n=22), and compared with wild-type (WT) mice (C57BL/6J, n=21) as controls. Results: PET/MRI, gamma counter measurements, and autoradiography showed the accumulation of Zr-89-Mal-HSA in the atherosclerotic lesions of Apoe(-/-) mice. The maximum standardized uptake values (SUVmax) for Zr-89-Mal-HSA at 16 and 20 weeks were 26% and 20% higher (P<0.05) in Apoe(-/-) mice than in control WT mice, whereas no difference in SUVmax was observed for F-18-FDG in the same animals. Zr-89-Mal-HSA uptake in the aorta, as evaluated by a gamma counter 48 h postinjection, was 32% higher (P<0.01) for Apoe(-/-) mice than in WT mice, and the aorta-to-blood ratio was 8-fold higher (P<0.001) for Zr-89-Mal-HSA compared with unspecific Zr-89-HSA. HSA-based probes were mainly distributed to the liver, spleen, kidneys, bone, and lymph nodes. The phosphor imaging autoradiography (PI-ARG) results corroborated the PET and gamma counter measurements, showing higher accumulation of Zr-89-Mal-HSA in the aortas of Apoe(-/-) mice than in WT mice (9.4 +/- 1.4 vs 0.8 +/- 0.3%; P<0.001). Conclusion: Zr-89 radiolabeling of Mal-HSA probes resulted in detectable activity in atherosclerotic lesions in aortas of Apoe(-/-) mice, as demonstrated by quantitative in vivo PET/MRI. Zr-89-Mal-HSA appears to be a promising diagnostic tool for the early identification of macrophage-rich areas of inflammation in atherosclerosis.
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| 14. |
- Dale, S, et al.
(författare)
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A mobile tomographic gamma camera system for acute studies
- 1997
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Ingår i: IEEE TRANSACTIONS ON NUCLEAR SCIENCE. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9499 .- 1558-1578. ; 44:2, s. 199-203
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Langdahl, Bente L., et al.
(författare)
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A 24-Month Study Evaluating the Efficacy and Safety of Denosumab for the Treatment of Men With Low Bone Mineral Density : Results From the ADAMO Trial
- 2015
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 100:4, s. 1335-1342
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Tidskriftsartikel (refereegranskat)abstract
- Context: One in 4 men in the United States aged >50 years will have an osteoporosis-related fracture. Fewer data are available on osteoporosis treatment in men than in women. Objective: The purpose of this study was to evaluate denosumab therapy in men with low bone mineral density (BMD). Design: This was a phase 3 study with 2 treatment periods: a previously reported 12-month double-blind, placebo-controlled phase and a 12-month open-label phase. Setting: This was a multicenter study conducted in North America and Europe. Participants: A total of 228 men entered the open-label phase and 219 completed the study. Intervention: Men from the original denosumab (long-term) and placebo (crossover) groups received 60 mg of denosumab sc every 6 months. Main Outcome Measures: BMD, serum collagen type I C-telopeptide, and safety were measured. Results: During the open-label phase, continued BMD increases occurred with long-term denosumab treatment (2.2% lumbar spine, 0.9% total hip, 1.3% femoral neck, 1.3% trochanter, and 0.2% 1/3 radius), resulting in cumulative 24-month gains from baseline of 8.0%, 3.4%, 3.4%, 4.6%, and 0.7%, respectively (all P < .01). The crossover group showed BMD gains after 12 months of denosumab treatment similar to those of the long-term denosumab group during the first treatment year. Significant reductions in serum collagen type I C-teleopeptide were observed after denosumab administration. Adverse event rates were similar between groups, and no new safety signals were identified. Conclusions: In men with low BMD, denosumab treatment for a second year continued to increase BMD, maintained reductions in bone resorption, and was well tolerated. BMD increased in men initiating denosumab during the second year. These effects were similar to those previously seen in postmenopausal women with osteoporosis and in men with prostate cancer receiving androgen deprivation therapy.
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| 16. |
- Leslie, William D, et al.
(författare)
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Selection of women aged 50-64 yr for bone density measurement.
- 2013
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Ingår i: Journal of Clinical Densitometry. - : Elsevier BV. - 1094-6950. ; 16:4, s. 570-8
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Tidskriftsartikel (refereegranskat)abstract
- The fracture risk assessment tool from the World Health Organization (FRAX(®)) estimates 10-yr major osteoporotic and hip fracture probabilities from multiple clinical risk factors and optionally femoral neck bone mineral density (BMD). FRAX without BMD has been proposed as a method to select postmenopausal women younger than 65yr for BMD measurement, but the efficiency of this strategy and its concordance with National Osteoporosis Foundation (NOF) treatment guidelines is unknown. The osteoporosis self-assessment test (OST) is another simple screening tool based on age and weight alone. A historical cohort of 18,315 women aged 50-64yr, drawn from the Manitoba Bone Density Program database, which contains clinical BMD results for the Province of Manitoba, Canada, was used to determine the performance of these screening tools in selecting postmenopausal women younger than 65yr for BMD testing. FRAX was closely aligned with indicators of high fracture risk (area under the receiver operating characteristic curve [AUROC]: 0.89), whereas OST was better for detecting women with osteoporotic BMD (AUROC: 0.72). The combination of major fracture probability 10% or higher from FRAX without BMD or OST less than 1 identified 42% of women for BMD testing, capturing 72% of women meeting any NOF treatment criteria (90% of women with NOF criteria for high risk from FRAX or prior fracture). The negative predictive value to exclude qualification for treatment under the NOF criteria was 90%. These data may help to inform an evidence-based approach for targeting BMD testing in postmenopausal women younger than 65yr under the NOF treatment guidelines.
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| 18. |
- Ntani, G., et al.
(författare)
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Patterns of change of multisite pain over 1 year of follow-up and related risk factors
- 2022
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Ingår i: European Journal of Pain. - : Wiley. - 1090-3801 .- 1532-2149. ; 26:7, s. 1499-1509
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Tidskriftsartikel (refereegranskat)abstract
- Background Multisite musculoskeletal pain is common and disabling. This study aimed to prospectively investigate the distribution of musculoskeletal pain anatomically, and explore risk factors for increases/reductions in the number of painful sites. Methods Using data from participants working in 45 occupational groups in 18 countries, we explored changes in reporting pain at 10 anatomical sites on two occasions 14 months apart. We used descriptive statistics to explore consistency over time in the number of painful sites, and their anatomical distribution. Baseline risk factors for increases/reductions by >= 3 painful sites were explored by random intercept logistic regression that adjusted for baseline number of painful sites. Results Among 8927 workers, only 20% reported no pain at either time point, and 16% reported >= 3 painful sites both times. After 14 months, the anatomical distribution of pain often changed but there was only an average increase of 0.17 painful sites. Some 14% workers reported a change in painful sites by >= 3. Risk factors for an increase of >= 3 painful sites included female sex, lower educational attainment, having a physically demanding job and adverse beliefs about the work-relatedness of musculoskeletal pain. Also predictives were as follows: older age, somatizing tendency and poorer mental health (each of which was also associated with lower odds of reductions of >= 3 painful sites). Conclusions Longitudinally, the number of reported painful sites was relatively stable but the anatomical distribution varied considerably. These findings suggest an important role for central pain sensitization mechanisms, rather than localized risk factors, among working adults. Significance Our findings indicate that within individuals, the number of painful sites is fairly constant over time, but the anatomical distribution varies, supporting the theory that among people at work, musculoskeletal pain is driven more by factors that predispose to experiencing or reporting pain rather than by localized stressors specific to only one or two anatomical sites.
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| 19. |
- O'Hanlon, Simon J., et al.
(författare)
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Recent Asian origin of chytrid fungi causing global amphibian declines
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 360:6389, s. 621-
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Tidskriftsartikel (refereegranskat)abstract
- Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of themost devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide.
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| 20. |
- Orwoll, Eric, et al.
(författare)
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A Randomized, Placebo-Controlled Study of the Effects of Denosumab for the Treatment of Men with Low Bone Mineral Density
- 2012
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 97:9, s. 3161-3169
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Tidskriftsartikel (refereegranskat)abstract
- Context: Men with low bone mineral density (BMD) were treated with denosumab.Objective: Our objective was to investigate the effects of denosumab compared with placebo in men with low BMD after 1 yr of treatment.Design, Subjects, and Intervention: This was a placebo-controlled, phase 3 study to investigate the efficacy and safety of denosumab 60 mg every 6 months vs. placebo in men with low BMD.Main Outcome Measure: The primary endpoint was the percent change from baseline in lumbar spine (LS) BMD at month 12.Results: Of the 242 randomized subjects (mean age 65 yr), 228 (94.2%) completed 1 yr of denosumab therapy. After 12 months, denosumab resulted in BMD increases of 5.7% at the LS, 2.4% at the total hip, 2.1% at the femoral neck, 3.1% at the trochanter, and 0.6% at the one third radius (adjusted P <= 0.0144 for BMD percent differences at all sites compared with placebo). Sensitivity analyses done by controlling for baseline covariates (such as baseline testosterone levels, BMD T-scores, and 10-yr osteoporotic fracture risk) demonstrated that the results of the primary endpoint were robust. Subgroup analyses indicate that treatment with denosumab was effective across a spectrum of clinical situations. Treatment with denosumab significantly reduced serum CTX levels at d 15 (adjusted P < 0.0001). The incidence of adverse events was similar between groups.Conclusions: One year of denosumab therapy in men with low BMD was well tolerated and resulted in a reduction in bone resorption and significant increases in BMD at all skeletal sites assessed.
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| 21. |
- Persaud, Shanta J., et al.
(författare)
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Pseudoislets as primary islet replacements for research Report on a symposium at King's College London, London UK
- 2010
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Ingår i: Islets. - : Informa UK Limited. - 1938-2014 .- 1938-2022. ; 2:4, s. 236-239
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Laboratory-based research aimed at understanding processes regulating insulin secretion and mechanisms underlying beta-cell dysfunction and loss in diabetes often makes use of rodents, as these processes are in many respects similar between rats/mice and humans. Indeed, a rough calculation suggests that islets have been isolated from as many as 150,000 rodents to generate the data contained within papers published in 2009 and the first four months of 2010. Rodent use for islet isolation has been mitigated, to a certain extent, by the availability of a variety of insulin-secreting cell lines that are used by researchers world-wide. However, when maintained as monolayers the cell lines do not replicate the robust, sustained secretory responses of primary islets which limits their usefulness as islet surrogates. On the other hand, there have been several reports that configuration of MIN6 beta-cells, derived from a mouse insulinoma, as three-dimensional cell clusters termed 'pseudoislets' largely recapitulates the function of primary islet beta-cells. The Diabetes Research Group at King's College London has been using the MIN6 pseudoislet model for over a decade and they hosted a symposium on "Pseudoislets as primary islet replacements for research", which was funded by the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), in London on 15(th) and 16(th) April 2010. This small, focused meeting was conceived as an opportunity to consolidate information on experiences of working with pseudoislets between different UK labs, and to introduce the theory and practice of pseudoislet culture to laboratories working with islets and/or beta-cell lines but who do not currently use pseudoislets. This short review summarizes the background to the development of the cell line-derived pseudoislet model, the key messages arising from the symposium and emerging themes for future pseudoislet research.
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| 22. |
- Persson, M, et al.
(författare)
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Three-dimensional total variation norm for SPECT reconstruction
- 2001
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Ingår i: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT. - 0168-9002. ; 471:1-2, s. 98-102
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 23. |
- Persson, M., et al.
(författare)
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Total variation norm for three-dimensional iterative reconstruction in limited view angle tomography
- 2001
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 46:3, s. 853-866
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Tidskriftsartikel (refereegranskat)abstract
- An iterative Bayesian reconstruction algorithm for limited view angle tomography, or ectomography, based on the three-dimensional total variation (TV) norm has been developed. The TV norm has been described ill the literature as a method for reducing noise in two-dimensional images while preserving edges, without introducing ringing or edge artefacts. It has also been proposed as a 2D regularization function in Bayesian reconstruction, implemented in an expectation maximization algorithm (TV-EM). The TV-EM was developed for 2D single photon emission computed tomography imaging, and the algorithm is capable of smoothing noise while maintaining edges without introducing artefacts. The TV norm was extended from 2D to 3D and incorporated into an ordered subsets expectation maximization algorithm for limited view angle geometry. The algorithm, called TV3D-EM, was evaluated using a modelled point spread function and digital phantoms. Reconstructed images were compared with those reconstructed with the 2D filtered backprojection algorithm currently used in ectomography. Results show a substantial reduction in artefacts related to the limited view angle geometry, and noise levels were also improved. Perhaps most important, depth resolution was improved by at least 45%. In conclusion, the proposed algorithm has been shown to improve the perceived image quality.
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| 24. |
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| 25. |
- von Bibra, H, et al.
(författare)
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[Contrast echocardiography]
- 2000
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Ingår i: Zeitschrift fur Kardiologie. - : Springer Science and Business Media LLC. - 0300-5860 .- 1435-1285. ; 8989 Suppl 1, s. 86-96
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Tidskriftsartikel (refereegranskat)
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| 26. |
- von Bibra, Helene, et al.
(författare)
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Contrast echocardiography
- 2000
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Ingår i: Zeitschrift für Kardiologie. - 0300-5860 .- 1435-1285. ; 89, s. 86-96
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Tidskriftsartikel (refereegranskat)abstract
- The intravenous application of an ultrasound contrast agent induces enhanced display of blood in all its pathways. Within cardiology, this principle is mainly utilized for signal enhancement of color Doppler and spectral Doppler in order to improve quantification of congenital and acquired valvular lesions and also for improved endocardial delineation during stress tests and in the evaluation of LV function. The new domaine of myocardial perfusion imaging by contrast echocardiography, however, needed profound technical developments before realization of the clinical potential could even be conceived. These are based on the complex reactions of microbubbbles in the acoustic field in order to allow the sensitive and bubble specific display of intramyocardial contrast effects. The presently available acquisition techniques, second harmonic imaging and harmonic power Doppler, demonstrate significant improvements if compared to traditional fundamental 2-d echocardiography, however, they are still subjected to important limitations. There are many anatomical, physiological, and technical reasons for insufficient display of intramyocardial microbubbles, the most important one being attenuation. It is hoped that the most recently developed imaging modality, pulse inversion technique, allows the necessary diagnostic accuracy and reproducibility in myocardial perfusion imaging.
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