318 results on '"Kuehl H"'
Search Results
152. COUPLING OF TRANSVERSE AND LONGITUDINAL WAVES BELOW THE SECOND ELECTRON CYCLOTRON HARMONIC.
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Kuehl, H
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- 1967
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153. Interference structure near the resonance cone
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Kuehl, H
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- 1973
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154. ELECTROMAGNETIC RADIATION FROM A DIPOLE IN AN ANISOTROPIC PLASMA
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Kuehl, H
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- 1961
155. LOW FREQUENCY RADIATION FROM AN ELECTRIC DIPOLE IN A COLD ANISOTROPIC PLASMA
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Kuehl, H
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- 1961
156. ASYMMETRICALLY EXCITED ELECTROMAGNETIC RADIATION FROM CIRCULAR CYLINDERS OF FINITE LENGTH AND PROLATE SPHEROIDS. Technical Report No. 19
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Kuehl, H
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- 1959
157. RELIABILITY ANALYSIS OF REACTOR SYSTEMS FROM THE VIEWPOINT OF THE CONSTRUCTOR AND OPERATOR.
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Kuehl, H
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- 1971
158. EXPERIMENTAL STUDY OF COUPLING TO CYCLOTRON HARMONIC RESONANCES.
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Kuehl, H
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- 1967
159. EXCITATION OF WAVES IN A WARM PLASMA BY AN ELECTRIC DIPOLE
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Kuehl, H
- Published
- 1962
160. Assessing the conservation status of the bonobo (Pan paniscus): results from Salonga National Park (DRC), and suggestions for a range-wide approach towards a new action plan
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Bessone, M, Fruth, B, Brown, R, and Kuehl, H
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QH301 ,QL ,GE - Abstract
All great ape species and subspecies are currently classified as endangered or critically endangered in the IUCN Red List, with wild populations declining at unprecedented rates. Among them, the bonobo (Pan paniscus) is perhaps the least known. With only 30% of its geographical range having been surveyed, the data needed for assessing its status and trend were lacking until 2016, preventing an update of its conservation status. Here, I investigated novel and traditional field methods for the assessment of bonobo populations, using data acquired in Salonga National Park (SNP), Democratic Republic of the Congo (DRC). First, I used 16,700 camera-trap videos to apply camera-trap distance sampling (CTDS), a recent method for estimating population density, to the bonobo and 13 other species. Second, I analysed 1,511 bonobo nests and 15 years of climatic data (2003���2018), to investigate factors involved in nest decay, evaluating the effects of inaccurate nest decay times on density estimates via traditional nest counts. Finally, I integrated datasets from 13 different surveys in SNP conducted over two time periods (2002-2008; 2012-2018) including detection/non-detection, count data and CTDS to estimate bonobo status and trend, using specifically calculated nest decay times. I showed that CTDS was an excellent method providing wildlife density and abundance, particularly important for threatened species, and highlighted issues in the application to different species, with reactivity to the cameras being the main source of bias for the bonobo. I found that decreasing precipitation triggered longer decay times of bonobo nests in SNP, with the number of storms being the main factor driving nest decay although a behavioural adaptation with bonobos strengthening nest structure in response to harsh precipitation. In addition, I showed that failure to account for nest-specific biotic and abiotic conditions, would lead to bonobo estimates biased up to 60%. Finally, I showed that an integrated analysis helped mitigating biases peculiar to specific survey methods, revealing an important, stable bonobo population in SNP. Here, a pristine habitat and the presence of rangers exerted a positive effect on bonobo abundance, as did ancestral taboos. The results of this thesis showed that new methodologies like CTDS, providing density estimates without the need of conversion factors, retain high potential for future population monitoring and conservation. Nevertheless, with necessary precautions such as application of time specific decay rates, implementation of traditional methods still provides accurate assessment of status and trend. The methods and recommendations described here are meant to serve as basis for a range-wide assessment, informing the new bonobo conservation strategy due in 2022.
161. Discovery of Novel Herpes Simplexviruses in Wild Gorillas, Bonobos, and Chimpanzees Supports Zoonotic Origin of HSV-2.
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Wertheim JO, Hostager R, Ryu D, Merkel K, Angedakin S, Arandjelovic M, Ayimisin EA, Babweteera F, Bessone M, Brun-Jeffery KJ, Dieguez P, Eckardt W, Fruth B, Herbinger I, Jones S, Kuehl H, Langergraber KE, Lee K, Madinda NF, Metzger S, Ormsby LJ, Robbins MM, Sommer V, Stoinski T, Wessling EG, Wittig RM, Yuh YG, Leendertz FH, and Calvignac-Spencer S
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- Animals, Herpesvirus 2, Human, Humans, Sequence Analysis, DNA, Hominidae virology, Phylogeny, Simplexvirus genetics, Viral Zoonoses
- Abstract
Viruses closely related to human pathogens can reveal the origins of human infectious diseases. Human herpes simplexvirus type 1 (HSV-1) and type 2 (HSV-2) are hypothesized to have arisen via host-virus codivergence and cross-species transmission. We report the discovery of novel herpes simplexviruses during a large-scale screening of fecal samples from wild gorillas, bonobos, and chimpanzees. Phylogenetic analysis indicates that, contrary to expectation, simplexviruses from these African apes are all more closely related to HSV-2 than to HSV-1. Molecular clock-based hypothesis testing suggests the divergence between HSV-1 and the African great ape simplexviruses likely represents a codivergence event between humans and gorillas. The simplexviruses infecting African great apes subsequently experienced multiple cross-species transmission events over the past 3 My, the most recent of which occurred between humans and bonobos around 1 Ma. These findings revise our understanding of the origins of human herpes simplexviruses and suggest that HSV-2 is one of the earliest zoonotic pathogens., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)
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- 2021
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162. Geographically structured genomic diversity of non-human primate-infecting Treponema pallidum subsp. pertenue .
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Mubemba B, Gogarten JF, Schuenemann VJ, Düx A, Lang A, Nowak K, Pléh K, Reiter E, Ulrich M, Agbor A, Brazzola G, Deschner T, Dieguez P, Granjon AC, Jones S, Junker J, Wessling E, Arandjelovic M, Kuehl H, Wittig RM, Leendertz FH, and Calvignac-Spencer S
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- Animals, Cote d'Ivoire, High-Throughput Nucleotide Sequencing, Monkey Diseases microbiology, Polymerase Chain Reaction, Treponema isolation & purification, Whole Genome Sequencing, Yaws microbiology, Yaws transmission, Cercocebus atys microbiology, Genome, Bacterial genetics, Monkey Diseases transmission, Treponema genetics, Yaws veterinary
- Abstract
Many non-human primate species in sub-Saharan Africa are infected with Treponema pallidum subsp. pertenue , the bacterium causing yaws in humans. In humans, yaws is often characterized by lesions of the extremities and face, while T. pallidum subsp. pallidum causes venereal syphilis and is typically characterized by primary lesions on the genital, anal or oral mucosae. It remains unclear whether other T. pallidum subspecies found in humans also occur in non-human primates and how the genomic diversity of non-human primate T. pallidum subsp. pertenue lineages is distributed across hosts and space. We observed orofacial and genital lesions in sooty mangabeys ( Cercocebus atys ) in Taï National Park, Côte d'Ivoire and collected swabs and biopsies from symptomatic animals. We also collected non-human primate bones from 8 species in Taï National Park and 16 species from 11 other sites across sub-Saharan Africa. Samples were screened for T. pallidum DNA using polymerase chain reactions (PCRs) and we used in-solution hybridization capture to sequence T. pallidum genomes. We generated three nearly complete T. pallidum genomes from biopsies and swabs and detected treponemal DNA in bones of six non-human primate species in five countries, allowing us to reconstruct three partial genomes. Phylogenomic analyses revealed that both orofacial and genital lesions in sooty mangabeys from Taï National Park were caused by T. pallidum subsp. pertenue . We showed that T. pallidum subsp. pertenue has infected non-human primates in Taï National Park for at least 28 years and has been present in two non-human primate species that had not been described as T. pallidum subsp. pertenue hosts in this ecosystem, western chimpanzees ( Pan troglodytes verus ) and western red colobus ( Piliocolobus badius ), complementing clinical evidence that started accumulating in Taï National Park in 2014. More broadly, simian T. pallidum subsp. pertenue strains did not form monophyletic clades based on host species or the symptoms caused, but rather clustered based on geography. Geographical clustering of T. pallidum subsp. pertenue genomes might be compatible with cross-species transmission of T. pallidum subsp. pertenue within ecosystems or environmental exposure, leading to the acquisition of closely related strains. Finally, we found no evidence for mutations that confer antimicrobial resistance.
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- 2020
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163. Public perception of predictive cancer genetic testing and research in Oregon.
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Alvord TW, Marriott LK, Nguyen PT, Shafer A, Brown K, Stoller W, Volpi JL, Vandehey-Guerrero J, Ferrara LK, Blakesley S, Solomon E, Kuehl H, Palma AJ, Farris PE, Hamman KJ, Cotter M, and Shannon J
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- Adult, Child, Family, Female, Focus Groups, Genetic Predisposition to Disease, Humans, Male, Middle Aged, Motivation, Neoplasms genetics, Oregon, Genetic Testing methods, Neoplasms diagnosis
- Abstract
The potential for using widespread genetic testing to inform health care has become a viable option, particularly for heritable cancers. Yet, little is known about how to effectively communicate the benefits and risks of both personal genetic testing and participation in biorepositories that aid scientific advancements. Nationwide efforts are engaging communities in large genetic studies to better estimate the population-wide prevalence of heritable cancers but have been met with hesitance or declination to participate in some communities. To successfully engage an Oregon population in longitudinal research that includes predictive genetic testing for pathogenic or likely pathogenic variants associated with an increased risk for cancer, researchers conducted 35 focus groups (two of which were held in Spanish) in 24 of Oregon's 36 counties to better understand knowledge and attitudes related to genetic testing and willingness to participate in longitudinal genetic research. A total of 203 adults (mean = 45.6 years; range 18-88), representing a range of education levels and prior knowledge of genetic research, participated in the focus groups. The majority (85%) of participants reported personal or family diagnoses of cancer (e.g., self, family, friends). A majority (87%) also reported a strong interest in cancer genetic testing and receiving genetic information about themselves. Nearly all focus groups (94%, 33 of 35 sites) included participant discussion citing their families (e.g., children, close relatives, and extended family members) as key motivators for participation in genetic research. For example, participants reported interest in increasing personal knowledge about their own and their families' cancer risks in order to respond proactively, if a pathogenic variant was found. While most focus groups (94%, 33 of 35 sites) included participant discussion describing barriers to predictive genetic, testing such as concerns about outcomes, the desire to learn about health risks in oneself mitigated or outweighed those fears for many participants. Other commonly reported concerns were related to potential mistrust of insurance companies, researchers, or institutions, or lack of knowledge about genetics, genetic testing, or genetic research. Participants, particularly in rural areas, highlighted critical factors for research recruitment, such as trust, personal interaction, public education about genetic research, and clear communication about study goals and processes. Our statewide findings reflect that public interest in predictive cancer genetic testing and cancer genetic research can surpass lack of knowledge of the complex topics, particularly when benefits for self and family are emphasized and when study considerations are well articulated., (© 2020 National Society of Genetic Counselors.)
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- 2020
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164. CD4 receptor diversity in chimpanzees protects against SIV infection.
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Bibollet-Ruche F, Russell RM, Liu W, Stewart-Jones GBE, Sherrill-Mix S, Li Y, Learn GH, Smith AG, Gondim MVP, Plenderleith LJ, Decker JM, Easlick JL, Wetzel KS, Collman RG, Ding S, Finzi A, Ayouba A, Peeters M, Leendertz FH, van Schijndel J, Goedmakers A, Ton E, Boesch C, Kuehl H, Arandjelovic M, Dieguez P, Murai M, Colin C, Koops K, Speede S, Gonder MK, Muller MN, Sanz CM, Morgan DB, Atencia R, Cox D, Piel AK, Stewart FA, Ndjango JN, Mjungu D, Lonsdorf EV, Pusey AE, Kwong PD, Sharp PM, Shaw GM, and Hahn BH
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- Animals, CD4 Antigens immunology, CD4-Positive T-Lymphocytes immunology, Evolution, Molecular, Genetic Variation immunology, HIV genetics, HIV pathogenicity, Humans, Pan troglodytes genetics, Pan troglodytes immunology, Polysaccharides genetics, Polysaccharides immunology, Simian Acquired Immunodeficiency Syndrome immunology, Simian Acquired Immunodeficiency Syndrome virology, Simian Immunodeficiency Virus pathogenicity, Viral Envelope Proteins immunology, CD4 Antigens genetics, Simian Acquired Immunodeficiency Syndrome genetics, Simian Immunodeficiency Virus genetics, Viral Envelope Proteins genetics
- Abstract
Human and simian immunodeficiency viruses (HIV/SIVs) use CD4 as the primary receptor to enter target cells. Here, we show that the chimpanzee CD4 is highly polymorphic, with nine coding variants present in wild populations, and that this diversity interferes with SIV envelope (Env)-CD4 interactions. Testing the replication fitness of SIVcpz strains in CD4
+ T cells from captive chimpanzees, we found that certain viruses were unable to infect cells from certain hosts. These differences were recapitulated in CD4 transfection assays, which revealed a strong association between CD4 genotypes and SIVcpz infection phenotypes. The most striking differences were observed for three substitutions (Q25R, Q40R, and P68T), with P68T generating a second N-linked glycosylation site (N66) in addition to an invariant N32 encoded by all chimpanzee CD4 alleles. In silico modeling and site-directed mutagenesis identified charged residues at the CD4-Env interface and clashes between CD4- and Env-encoded glycans as mechanisms of inhibition. CD4 polymorphisms also reduced Env-mediated cell entry of monkey SIVs, which was dependent on at least one D1 domain glycan. CD4 allele frequencies varied among wild chimpanzees, with high diversity in all but the western subspecies, which appeared to have undergone a selective sweep. One allele was associated with lower SIVcpz prevalence rates in the wild. These results indicate that substitutions in the D1 domain of the chimpanzee CD4 can prevent SIV cell entry. Although some SIVcpz strains have adapted to utilize these variants, CD4 diversity is maintained, protecting chimpanzees against infection with SIVcpz and other SIVs to which they are exposed., Competing Interests: The authors declare no conflict of interest., (Copyright © 2019 the Author(s). Published by PNAS.)- Published
- 2019
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165. Effects of Land cover change on Great Apes distribution at the Lobéké National Park and its surrounding Forest Management Units, South-East Cameroon. A 13 year time series analysis.
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Yuh YG, Dongmo ZN, N'Goran PK, Ekodeck H, Mengamenya A, Kuehl H, Sop T, Tracz W, Agunbiade M, and Elvis T
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- Animals, Biomass, Cameroon, Models, Statistical, Nesting Behavior, Parks, Recreational statistics & numerical data, Animal Distribution, Forests, Hominidae physiology
- Abstract
Understanding the effects of land cover change on wildlife distribution is very important for resource management and conservation planning. This paper aimed at detecting the effects of land cover change on great apes distribution at the Lobéké National Park and its bounded forest management units (FMUs). Data on great ape nests were collected in the field for the years 2001 and 2014 through distance sampling with line transects. Landsat TM images of South-East Cameroon for the years 2001 and 2014 were acquired from earth explorer and corrected atmospherically for proper visualization. An area of interest comprising the Lobéké National Park and its FMUs was extracted for classification and change detection. A comparison in great apes nest distribution and change per land cover change category was done for both years through point pattern analysis, whereas a time series analysis of the detected land cover change impacts on great apes nest distribution for a period of 13 years was modeled using logistic growth and regression equations in Vensim 7.2. The results could illustrate that, as land cover changes from one cover type in 2001 to another in 2014, increases or decreases in great apes nests were observed within each changed area.
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- 2019
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166. Nocturnal activity in wild chimpanzees (Pan troglodytes): Evidence for flexible sleeping patterns and insights into human evolution.
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Tagg N, McCarthy M, Dieguez P, Bocksberger G, Willie J, Mundry R, Stewart F, Arandjelovic M, Widness J, Landsmann A, Agbor A, Angedakin S, Ayimisin AE, Bessone M, Brazzola G, Corogenes K, Deschner T, Dilambaka E, Eno-Nku M, Eshuis H, Goedmakers A, Granjon AC, Head J, Hermans V, Jones S, Kadam P, Kambi M, Langergraber KE, Lapeyre V, Lapuente J, Lee K, Leinert V, Maretti G, Marrocoli S, Meier A, Nicholl S, Normand E, Ormsby LJ, Piel A, Robinson O, Sommer V, Ter Heegde M, Tickle A, Ton E, van Schijndel J, Vanleeuwe H, Vergnes V, Wessling E, Wittig RM, Zuberbuehler K, Kuehl H, and Boesch C
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- Animals, Anthropology, Physical, Biological Evolution, Ecosystem, Humans, Temperature, Behavior, Animal physiology, Pan troglodytes physiology, Sleep physiology, Wakefulness physiology
- Abstract
Objectives: We investigated occurrences and patterns of terrestrial nocturnal activity in wild chimpanzees (Pan troglodytes) and modelled the influence of various ecological predictors on nocturnal activity., Methods: Data were extracted from terrestrial camera-trap footage and ecological surveys from 22 chimpanzee study sites participating in the Pan African Programme: The Cultured Chimpanzee. We described videos demonstrating nocturnal activity, and we tested the effects of the percentage of forest, abundance of predators (lions, leopards and hyenas), abundance of large mammals (buffalos and elephants), average daily temperature, rainfall, human activity, and percent illumination on the probability of nocturnal activity., Results: We found terrestrial nocturnal activity to occur at 18 of the 22 study sites, at an overall average proportion of 1.80% of total chimpanzee activity, and to occur during all hours of the night, but more frequently during twilight hours. We found a higher probability of nocturnal activity with lower levels of human activity, higher average daily temperature, and at sites with a larger percentage of forest. We found no effect of the abundance of predators and large mammals, rainfall, or moon illumination., Discussion: Chimpanzee terrestrial nocturnal activity appears widespread yet infrequent, which suggests a consolidated sleeping pattern. Nocturnal activity may be driven by the stress of high daily temperatures and may be enabled at low levels of human activity. Human activity may exert a relatively greater influence on chimpanzee nocturnal behavior than predator presence. We suggest that chimpanzee nocturnal activity is flexible, enabling them to respond to changing environmental factors., (© 2018 Wiley Periodicals, Inc.)
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- 2018
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167. Persistent anthrax as a major driver of wildlife mortality in a tropical rainforest.
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Hoffmann C, Zimmermann F, Biek R, Kuehl H, Nowak K, Mundry R, Agbor A, Angedakin S, Arandjelovic M, Blankenburg A, Brazolla G, Corogenes K, Couacy-Hymann E, Deschner T, Dieguez P, Dierks K, Düx A, Dupke S, Eshuis H, Formenty P, Yuh YG, Goedmakers A, Gogarten JF, Granjon AC, McGraw S, Grunow R, Hart J, Jones S, Junker J, Kiang J, Langergraber K, Lapuente J, Lee K, Leendertz SA, Léguillon F, Leinert V, Löhrich T, Marrocoli S, Mätz-Rensing K, Meier A, Merkel K, Metzger S, Murai M, Niedorf S, De Nys H, Sachse A, van Schijndel J, Thiesen U, Ton E, Wu D, Wieler LH, Boesch C, Klee SR, Wittig RM, Calvignac-Spencer S, and Leendertz FH
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- Africa South of the Sahara, Animal Diseases microbiology, Animals, Anthrax microbiology, Anthrax mortality, Bacillus anthracis isolation & purification, Diptera microbiology, Extinction, Biological, Female, Male, Pan troglodytes microbiology, Parks, Recreational, Phylogeny, Animal Diseases mortality, Animals, Wild microbiology, Anthrax veterinary, Bacillus anthracis pathogenicity, Mammals microbiology, Rainforest, Tropical Climate
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Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities. Using data and samples collected over three decades, we show that rainforest anthrax is a persistent and widespread cause of death for a broad range of mammalian hosts. We predict that this pathogen will accelerate the decline and possibly result in the extirpation of local chimpanzee (Pan troglodytes verus) populations. We present the epidemiology of a cryptic pathogen and show that its presence has important implications for conservation.
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- 2017
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168. The SHIELD (Safety & Health Improvement: Enhancing Law Enforcement Departments) Study: Mixed Methods Longitudinal Findings.
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Kuehl KS, Elliot DL, MacKinnon DP, O'Rourke HP, DeFrancesco C, Miočević M, Valente M, Sleigh A, Garg B, McGinnis W, and Kuehl H
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- Adult, Alcohol Drinking, Diet, Exercise, Female, Humans, Life Style, Male, Middle Aged, Oregon, Quality of Life, Sleep, Stress, Psychological prevention & control, Tobacco Use, Washington, Health Behavior, Health Promotion, Occupational Health Services, Police, Program Evaluation
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The SHIELD (Safety & Health Improvement: Enhancing Law Enforcement Departments) Study is a worksite wellness team-based intervention among police and sheriff departments assessing the program's effectiveness to reduce occupational risks and unhealthy lifestyle behaviors. The SHIELD program focused on improving diet, physical activity, body weight and sleep, and reducing the effects of unhealthy stress and behaviors, such as tobacco and substance abuse. The SHIELD team-based health promotion program was found to be feasible and effective at 6 months in improving diet, sleep, stress, and overall quality of life of law enforcement department personnel. Both intervention and control groups were followed for 24 months, and we report those durability findings, along with qualitative group interview results that provide insight into the changes of the long-term outcomes. Long-term effects were observed for consumption of fruits and vegetables, and there was some evidence for effects on tobacco and alcohol use. Assessment of dietary habits, physical activity behaviors, weight loss maintenance, and substance use is rare more than 1 year following an intervention, and in general, initial positive changes do not persist in prior research. The SHIELD program was feasible, effective, and durable for improving dietary changes.
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- 2016
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169. Prognostic value of (18)F-fluorodeoxyglucose PET-CT imaging in acute aortic syndromes: comparison with serological biomarkers of inflammation.
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Gorla R, Erbel R, Kuehl H, Kahlert P, Tsagakis K, Jakob H, Mahabadi AA, Schlosser T, Bockisch A, Eggebrecht H, Bossone E, and Jánosi RA
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- Acute Disease, Aged, Aged, 80 and over, Aortic Diseases blood, Aortic Diseases diagnostic imaging, Aortic Diseases mortality, Aortic Diseases therapy, Biomarkers blood, C-Reactive Protein analysis, Discriminant Analysis, Disease Progression, Female, Fibrin Fibrinogen Degradation Products analysis, Hospitalization, Humans, Male, Middle Aged, Predictive Value of Tests, Retreatment, Retrospective Studies, Risk Factors, Syndrome, Time Factors, Treatment Outcome, Aortic Diseases diagnosis, Fluorodeoxyglucose F18 administration & dosage, Inflammation Mediators blood, Multimodal Imaging methods, Positron-Emission Tomography, Radiopharmaceuticals administration & dosage, Serologic Tests, Tomography, X-Ray Computed
- Abstract
Aim of this study was to investigate the relationship between (18)F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) findings and serological biomarkers of inflammation and the related discriminant value of unfavourable outcome during follow-up in patients with acute aortic syndromes (AAS). Sixty patients with AAS underwent PET-CT imaging during the hospitalization along with measurement of C-reactive protein (CRP) and D-dimer (D-d) serum levels. An aortic wall pathology was considered PET-positive by a maximum standardized uptake value (SUVmax) >2.5. A combined endpoint of major adverse events (MAE) including aorta-related mortality, disease progression and re-intervention was used to compare patient subgroups at 3-year follow-up. PET-CT detected an elevated FDG uptake within the aortic wall in 25 (41.7%) patients. PET-positive patients showed significantly increased CRP levels (10.0 ± 6.6 mg/dL) and tended to higher D-d levels (5.1 ± 3.9 mg/L), compared to PET-negative patients (5.8 ± 6.1 mg/dL and 3.1 ± 4.7 mg/L respectively; P = 0.048, P = 0.19). At 3-year follow-up, all-cause mortality and MAE were higher in the PET-positive (21.7 and 47.8% respectively) than PET-negative group (0.0 and 13.3% respectively; P = 0.012, P = 0.006). On Kaplan-Meier analysis, PET-positive patients were at higher risk of MAE (P = 0.031). This tendency was more evident by combining PET results with D-d levels at a cutoff value of 4.8 mg/L (P < 0.001). In patients with AAS, a pathological glucose uptake in aortic wall lesions by PET-CT was associated with high CRP levels and increased mortality and MAE at 3-year follow-up. The combination of PET results with D-d levels had the best discriminant value of MAE.
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- 2015
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170. Whole-body [¹⁸F]FDG PET/MRI vs. PET/CT in the assessment of bone lesions in oncological patients: initial results.
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Beiderwellen K, Huebner M, Heusch P, Grueneisen J, Ruhlmann V, Nensa F, Kuehl H, Umutlu L, Rosenbaum-Krumme S, and Lauenstein TC
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- Bone Neoplasms secondary, Diagnosis, Differential, Female, Follow-Up Studies, Humans, Male, Middle Aged, Neoplasm Metastasis, Prospective Studies, Radiopharmaceuticals, Reproducibility of Results, Bone Neoplasms diagnosis, Fluorodeoxyglucose F18, Magnetic Resonance Imaging methods, Positron-Emission Tomography methods, Tomography, X-Ray Computed methods, Whole Body Imaging methods
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Objectives: To compare [(18)F]FDG PET/MRI with PET/CT for the assessment of bone lesions in oncologic patients., Methods: This prospective study included 67 patients with solid tumours scheduled for PET/CT with [(18)F]FDG who also underwent a whole-body PET/MRI scan. The datasets (PET/CT, PET/MRI) were rated by two readers regarding lesion conspicuity (four-point scale) and diagnostic confidence (five-point scale). Median scores were compared using the Wilcoxon test., Results: Bone metastases were present in ten patients (15%), and benign bone lesions in 15 patients (22%). Bone metastases were predominantly localized in the pelvis (18 lesions, 38%) and the spine (14 lesions, 29%). Benign bone lesions were exclusively osteosclerotic and smaller than the metastases (mean size 6 mm vs. 23 mm). While PET/CT allowed identification of 45 of 48 bone metastases (94%), PET/MRI allowed identification of all bone metastases (100%). Conspicuity of metastases was high for both modalities with significantly better results using PET/MRI (p < 0.05). Diagnostic confidence in lesion detection was high for both modalities without a significant difference. In benign lesions, conspicuity and diagnostic confidence were significantly higher with PET/CT (p < 0.05)., Conclusions: [(18)F]FDG PET/MRI shows high potential for the assessment of bone metastases by offering superior lesion conspicuity when compared to PET/CT. In hypersclerotic, benign bone lesions PET/CT still sets the reference., Key Points: • PET/MRI and PET/CT are of equal value for the identification of disease-positive patients • PET/MRI offers higher lesion conspicuity as well as diagnostic confidence • PET/MRI is an attractive new alternative for the assessment of bone metastases.
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- 2014
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171. Depiction and characterization of liver lesions in whole body [¹⁸F]-FDG PET/MRI.
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Beiderwellen K, Gomez B, Buchbender C, Hartung V, Poeppel TD, Nensa F, Kuehl H, Bockisch A, and Lauenstein TC
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- Adult, Aged, Algorithms, Female, Humans, Image Enhancement methods, Male, Middle Aged, Radiopharmaceuticals, Reproducibility of Results, Sensitivity and Specificity, Young Adult, Fluorodeoxyglucose F18, Image Interpretation, Computer-Assisted methods, Liver Neoplasms diagnosis, Magnetic Resonance Imaging methods, Multimodal Imaging methods, Positron-Emission Tomography methods, Whole Body Imaging methods
- Abstract
Objectives: To assess the value of PET/MRI with [(18)F]-FDG using a whole body protocol for the depiction and characterization of liver lesions in comparison to PET/CT., Methods: 70 patients (31 women, 39 men) with solid tumors underwent [(18)F]-FDG PET/CT and followed by an additional PET/MRI using an integrated scanner. Two readers rated the datasets (PET/CT; PET/MRI) regarding conspicuity of hepatic lesions (4-point ordinal scale) and diagnostic confidence (5-point ordinal scale). Median scores for lesion conspicuity and diagnostic confidence were compared using Wilcoxon's rank sum test. Prior examinations, histopathology and clinical follow-up (116 ± 54 days) served as standard of reference., Results: 36 of 70 (51%) patients showed liver lesions. Using PET/CT and PET/MRI all patients with liver metastases could correctly be identified. A total of 97 lesions were found (malignant n=26; benign n=71). For lesion conspicuity significantly higher scores were obtained for PET/MRI in comparison to PET/CT (p<0.001). Significantly better performance for diagnostic confidence was observed in PET/MRI, both for malignant as for benign lesions (p<0.001)., Conclusions: PET/MRI, even in the setting of a whole body approach, provides higher lesion conspicuity and diagnostic confidence compared to PET/CT and may therefore evolve as an attractive alternative in oncologic imaging., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)
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- 2013
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172. Dental Ultrasound Diagnostics - a Simulation Study.
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Petersen S, Glock H, Specht O, Kuehl H, Heinitz W, Warkentin M, and Behrend D
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- 2013
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173. Optimizing positron emission tomography image acquisition protocols in integrated positron emission tomography/magnetic resonance imaging.
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Hartung-Knemeyer V, Beiderwellen KJ, Buchbender C, Kuehl H, Lauenstein TC, Bockisch A, and Poeppel TD
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- Contrast Media, Diagnosis, Differential, Female, Fluorodeoxyglucose F18, Humans, Male, Middle Aged, Observer Variation, Organometallic Compounds, Radiopharmaceuticals, Reproducibility of Results, Signal-To-Noise Ratio, Time Factors, Image Processing, Computer-Assisted methods, Magnetic Resonance Imaging methods, Neoplasms diagnosis, Positron-Emission Tomography methods
- Abstract
Objectives: In integrated positron emission tomography (PET)/magnetic resonance imaging (MRI), the PET data acquisition is performed simultaneously to the magnetic resonance data acquisition, leaving latitude for the duration of PET acquisition time. This establishes emission time as an important parameter in forthcoming PET/MRI protocols because it is one of the key factors determining PET image quality. Thus, the purpose of the current study was to identify optimal duration of PET acquisition time in PET/MRI., Materials and Methods: A total of 22 consecutive patients (7 men, 15 women) underwent fluorine-18-labeled fluorodeoxyglucose (18[F]FDG) PET/MRI after clinical PET/computed tomography. Positron emission tomography/magnetic resonance scans were acquired for 8 minutes per bed position (mpb). Positron emission tomography was extracted to reconstruct images with 2, 4, 6, and 8 mpb for each patient. Visual and quantitative approaches were used to assess image quality and lesion detectability for each image. For image quality, (a) 3 readers independently scored subjective image quality on a 4-point scale and (b) a region-of-interest approach was used to obtain a quantitative estimate of image quality in terms of noise. For lesion detectability, (a) the readers independently counted the number of hypermetabolic lesions and (b) signal-to-noise ratio and contrast-to-noise ratio were computed in a region-of-interest approach. Moreover, the mean and maximal standardized uptake value (SUV mean and SUV max, respectively) of the hypermetabolic lesions was compared across all acquisition times., Results: For image quality, subjective image quality significantly declined from 8 to 2 mpb (P <; 0.05), with the exception of the difference between 6 and 8 mpb. Image noise increased with shorter imaging duration, ranging from 13% on average in the 8-mpb scans to 23% in the 2-mpb scans (differences were statistically significant for 2 vs 6 mpb, 2 vs 8 mpb, and 4 vs 8 mpb; P <; 0.05). For lesion detectability, 39 hypermetabolic lesions were identified by consensus. There was no difference in detected lesions across all acquisition times. Signal-to-noise ratio and contrast-to-noise ratio were constantly high and did not differ significantly across the acquisition times. The SUV mean and SUV max did not differ significantly across all acquisition times., Conclusions: Positron emission tomography acquisition times on integrated PET/MRI do not need to exceed usual acquisition times on current PET/computed tomography scanners: Although the PET image quality suffers from short acquisition times, even a duration of 2 mpb permits sufficient lesion detection. Moreover, quantitative measures of tracer uptake are also reasonably precise at short acquisition times.
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- 2013
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174. Simultaneous 68Ga-DOTATOC PET/MRI in patients with gastroenteropancreatic neuroendocrine tumors: initial results.
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Beiderwellen KJ, Poeppel TD, Hartung-Knemeyer V, Buchbender C, Kuehl H, Bockisch A, and Lauenstein TC
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- Adult, Aged, Contrast Media, Diagnosis, Differential, Female, Gastrointestinal Neoplasms diagnosis, Gastrointestinal Tract diagnostic imaging, Gastrointestinal Tract pathology, Humans, Image Enhancement methods, Iohexol analogs & derivatives, Male, Multimodal Imaging methods, Pancreas diagnostic imaging, Pancreas pathology, Pancreatic Neoplasms diagnosis, Pilot Projects, Prospective Studies, Reproducibility of Results, Tomography, X-Ray Computed, Whole Body Imaging methods, Gallium Radioisotopes, Magnetic Resonance Imaging methods, Neuroendocrine Tumors diagnosis, Octreotide analogs & derivatives, Organometallic Compounds, Positron-Emission Tomography methods
- Abstract
Objectives: The aim of this pilot study was to demonstrate the potential of simultaneously acquired 68-Gallium-DOTA-D-Phe1-Tyr3-octreotide (68Ga-DOTATOC) positron emission tomography/magnetic resonance imaging (PET/MRI) in comparison with 68Ga-DOTATOC PET/computed tomography (PET/CT) in patients with known gastroenteropancreatic neuroendocrine tumors (NETs)., Materials and Methods: Eight patients (4 women and 4 men; mean [SD] age, 54 [17] years; median, 55 years; range 25-74 years) with histopathologically confirmed NET and scheduled 68Ga-DOTATOC PET/CT were prospectively enrolled for an additional integrated PET/MRI scan. Positron emission tomography/computed tomography was performed using a triple-phase contrast-enhanced full-dose protocol. Positron emission tomography/magnetic resonance imaging encompassed a diagnostic, contrast-enhanced whole-body MRI protocol. Two readers separately analyzed the PET/CT and PET/MRI data sets including their subscans in random order regarding lesion localization, count, and characterization on a 4-point ordinal scale (0, not visible; 1, benign; 2, indeterminate; and 3, malignant). In addition, each lesion was rated in consensus on a binary scale (allowing for benign/malignant only). Clinical imaging, existing prior examinations, and histopathology (if available) served as the standard of reference. In PET-positive lesions, the standardized uptake value (SUV max) was measured in consensus. A descriptive, case-oriented data analysis was performed, including determination of frequencies and percentages in detection of malignant, benign, and indeterminate lesions in connection to their localization. In addition, percentages in detection by a singular modality (such as PET, CT, or MRI) were calculated. Interobserver variability was calculated (Cohen's κ). The SUVs in the lesions in PET/CT and PET/MRI were measured, and the correlation coefficient (Pearson, 2-tailed) was calculated., Results: According to the reference standard, 5 of the 8 patients had malignant NET lesions at the time of the examination. A total of 4 patients were correctly identified by PET/CT, with the PET and CT component correctly identifying 3 patients each. All 5 patients positive for NET disease were correctly identified by PET/MRI, with the MRI subscan identifying all 5 patients and the PET subscan identifying 3 patients. All lesions considered as malignant in PET/CT were equally depicted in and considered using PET/MRI. One liver lesion rated as "indetermined" in PET/CT was identified as metastasis in PET/MRI because of a diffusion restriction in diffusion-weighted imaging. Of the 4 lung lesions characterized in PET/CT, only 1 was depicted in PET/MRI. Of the 3 lymph nodes depicted in PET/CT, only 1 was characterized in PET/MRI. Interobserver reliability was equally very good in PET/CT (κ = 0.916) and PET/MRI (κ = 1.0). The SUV max measured in PET/CT and in PET/MRI showed a strong correlation (Pearson correlation coefficient, 0.996)., Conclusions: This pilot study demonstrates the potential of 68Ga-DOTATOC PET/MRI in patients with gastroenteropancreatic NET, with special advantages in the characterization of abdominal lesions yet certain weaknesses inherent to MRI, such as lung metastases and hypersclerotic bone lesions.
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- 2013
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175. Factors in adoption of a fire department wellness program: champ-and-chief model.
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Kuehl H, Mabry L, Elliot DL, Kuehl KS, and Favorite KC
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- Humans, Oregon, Prospective Studies, Qualitative Research, Risk Reduction Behavior, Washington, Firefighters, Health Promotion organization & administration, Models, Organizational, Occupational Health
- Abstract
Objective: To identify and evaluate determinants of fire departments' wellness program adoption., Methods: The Promoting Healthy Lifestyles: Alternative Models' Effects fire service wellness program was offered for free to all medium-sized fire departments in Oregon and Washington. An invitation to participate was mailed to key fire department decision makers (chief, union president, and wellness officer). These key decision makers from 12 sites that adopted the program and 24 matched nonadopting sites were interviewed and results were analyzed to define adoption determinants., Results: Three adoption requirements were identified: (1) mailer connection, (2) local firefighter wellness champion, and (3) willing fire chief, whereas a fourth set of organizational factors had little or no impact on adoption including previous and ongoing wellness activities, financial pressures, and resistance to change., Conclusions: Findings identified determinants of medium-sized fire service wellness program adoption.
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- 2013
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176. Selective and sequential transarterial chemoembolization: survival in patients with hepatocellular carcinoma.
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Antoch G, Roelle G, Ladd SC, Kuehl H, Heusner TA, Sotiropoulos GC, Hilgard P, Forsting M, and Verhagen R
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- Antineoplastic Agents therapeutic use, Female, Germany epidemiology, Hemostatics therapeutic use, Humans, Male, Middle Aged, Prevalence, Risk Factors, Survival Analysis, Survival Rate, Treatment Outcome, Carcinoma, Hepatocellular mortality, Carcinoma, Hepatocellular therapy, Chemoembolization, Therapeutic mortality, Ethiodized Oil therapeutic use, Liver Neoplasms mortality, Liver Neoplasms therapy, Mitomycin therapeutic use
- Abstract
Purpose: To assess the survival time of patients with HCC following transarterial chemoembolization performed in a highly selective and sequential way., Patients and Methods: 124 HCC patients (102 male, 22 female; mean age 63±11 years) treated with selective and sequential chemoembolization at a single center were included. Selective chemoembolization was performed through a coaxially introduced microcatheter in a segmental or subsegmental hepatic artery. Treatment was stopped after complete stasis of the blood flow in the tumor-feeding vessel. The primary endpoint of the study was overall survival., Results: The median overall survival of the entire patient population was 27.2 months (mo) (±8.9 mo, 95% CI 9.8 mo, 44.6 mo). When stratified according to liver function the median survival was 46.1 mo (±9.0 mo; 95% CI 28.5 mo, 63.7 mo) for Child-Pugh A and 11.1 mo (±4.3 mo; 95% CI 2.7 mo, 19.5 mo) for Child-Pugh B (p<.001). The median survival was 46.1 mo (±16.6 mo; 95% CI 13.5 mo, 78.7 mo) for BCLC stage A, 19.7 mo (±2.6 mo; 95% CI 14.6 mo, 24.8 mo) for BCLC stage B, and 14.4 mo (±5.0 mo; 95% CI 4.5 mo, 24.3 mo) for BCLC stage C (p<.01)., Conclusion: Selective and sequential chemoembolization offers long survival times in patients with HCC. Those patients with preserved liver function benefit more than patients with limited liver reserve., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)
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- 2012
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177. Changes in staging for hepatocellular carcinoma after radiofrequency ablation prior to liver transplantation as found in the explanted liver.
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Schroeder T, Sotiropoulos GC, Molmenti EP, Kuehl H, Cicinnati VR, Schmitz KJ, Kóbori L, Paul A, and Mathé Z
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- Disease Progression, Humans, Neoplasm Staging, Catheter Ablation, Liver Neoplasms pathology, Liver Neoplasms surgery, Liver Transplantation
- Abstract
Background/aims: To analyze the efficacy of radiofrequency ablation (RFA) prior to liver transplantation (LT) in liver explants., Methodology: We reviewed pathological findings in the explanted livers of 13 patients with histologically proven HCC and liver cirrhosis who underwent RFA as bridging treatment prior to LT. Eight patients had solitary nodules with a median diameter of 4cm, whereas five patients had two tumors each with a median total diameter of 3.3cm prior to RFA. One session of RFA was performed by all patients., Results: Tumor regression was proved in 3/13 patients whereas steady disease was observed in 5/13 patients (38%). Tumor regression was observed only in one of the five patients having two tumors prior to RFA. Pathology proved a multifocal tumor in four patients, including one patient with a radiological presumed solitary tumor. Tumor progression was observed in 5/13 patients (38%)., Conclusions: Although the majority of our patients (8/13, 62%) had a solitary tumor at the beginning of treatment, tumor progression was observed in a large proportion (38%) among them. The underestimation of tumor lesions in radiology and partial necrosis of the tumor achieved in most patients limit the role of RFA as bridging treatment prior to LT.
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- 2011
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178. The impact of 68Ga-DOTATOC positron emission tomography/computed tomography on the multimodal management of patients with neuroendocrine tumors.
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Frilling A, Sotiropoulos GC, Radtke A, Malago M, Bockisch A, Kuehl H, Li J, and Broelsch CE
- Subjects
- Adult, Aged, Disease Progression, Female, Gallium Radioisotopes, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Neoplasm Staging, Neuroendocrine Tumors pathology, Sensitivity and Specificity, Whole Body Imaging, Neuroendocrine Tumors diagnostic imaging, Octreotide analogs & derivatives, Positron-Emission Tomography methods, Radiopharmaceuticals, Tomography, X-Ray Computed methods
- Abstract
Objective: To evaluate the impact of 68Ga-DOTATOC positron emission tomography (PET)/computed tomography (CT) on the multimodal management of neuroendocrine tumors (NET)., Background: Establishment of the extent and progression of NET are necessary to decide which treatment option to choose. However, morphological imaging with CT or magnetic resonance imaging (MRI) is often inadequate in identifying the primary tumor and/or in detecting small metastatic lesions., Methods: In total, 52 patients (27 women and 25 men) with histologically proven NET could be included in the protocol of comparison between 68Ga-DOTATOC PET/CT and CT and/or MRI. The examinations were performed in terms of tumor staging and, in some instances, also of primary tumor site identification to evaluate the patient's eligibility for treatment. Each patient presented with either CT and/or MRI performed elsewhere and consecutively underwent 68Ga-DOTATOC PET/CT in our institution., Results: In all 52 patients, 68Ga-DOTATOC PET/CT demonstrated pathologically increased uptake for at least 1 tumor site, yielding a sensitivity of 100% on a patient basis. In 3 of 4 patients with unknown primary tumor site, 68Ga-DOTATOC PET/CT visualized the primary tumor region (jejunum, ileum, and pancreas, respectively) not identified on CT and/or MRI. 68Ga-DOTATOC PET/CT detected additional hepatic and/or extrahepatic metastases in 22 of the 33 patients diagnosed with hepatic metastases on CT and/or MRI. Of the 15 patients evaluated for liver transplantation, we omitted 7 (46.6%) from further screening because of evidence of metastatic deposits not seen by conventional imaging. Overall, 68Ga-DOTATOC PET/CT altered our treatment decision based on CT and/or MRI alone, in 31 (59.6%) of the 52 patients., Conclusions: In this study, 68Ga-DOTATOC PET/CT proved clearly superior to CT and/or MRI for detection and staging of NET. More important, 68Ga-DOTATOC PET/CT impacted our treatment decision in more than every second patient.
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- 2010
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179. Flow-targeted inversion-prepared b-TFE coronary MR angiography: initial results in patients.
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Katoh M, Spüntrup E, Kuehl H, Stuber M, Günther RW, and Botnar RM
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- Adult, Blood Flow Velocity physiology, Coronary Stenosis physiopathology, Electrocardiography, Female, Humans, Male, Middle Aged, Reference Values, Sensitivity and Specificity, Signal Processing, Computer-Assisted, Coronary Angiography methods, Coronary Circulation physiology, Coronary Stenosis diagnosis, Image Enhancement methods, Image Processing, Computer-Assisted methods, Imaging, Three-Dimensional methods, Magnetic Resonance Angiography methods
- Abstract
Purpose: Visualization of coronary blood flow in the right and left coronary system in volunteers and patients by means of a modified inversion-prepared bright-blood coronary magnetic resonance angiography (cMRA) sequence., Materials and Methods: cMRA was performed in 14 healthy volunteers and 19 patients on a 1.5 Tesla MR system using a free-breathing 3D balanced turbo field echo (b-TFE) sequence with radial k-space sampling. For magnetization preparation a slab selective and a 2D selective inversion pulse were used for the right and left coronary system, respectively. cMRA images were evaluated in terms of clinically relevant stenoses (< 50 %) and compared to conventional catheter angiography. Signal was measured in the coronary arteries (coro), the aorta (ao) and in the epicardial fat (fat) to determine SNR and CNR. In addition, maximal visible vessel length, and vessel border definition were analyzed., Results: The use of a selective inversion pre-pulse allowed direct visualization of the coronary blood flow in the right and left coronary system. The measured SNR and CNR, vessel length, and vessel sharpness in volunteers (SNR coro: 28.3 +/- 5.0; SNR ao: 37.6 +/- 8.4; CNR coro-fat: 25.3 +/- 4.5; LAD: 128.0 cm +/- 8.8; RCA: 74.6 cm +/- 12.4; Sharpness: 66.6 % +/- 4.8) were slightly increased compared to those in patients (SNR coro: 24.1 +/- 3.8; SNR ao: 33.8 +/- 11.4; CNR coro-fat: 19.9 +/- 3.3; LAD: 112.5 cm +/- 13.8; RCA: 69.6 cm +/- 16.6; Sharpness: 58.9 % +/- 7.9; n.s.). In the patient study the assessment of 42 coronary segments lead to correct identification of 10 clinically relevant stenoses., Conclusion: The modification of a previously published inversion-prepared cMRA sequence allowed direct visualization of the coronary blood flow in the right as well as in the left coronary system. In addition, this sequence proved to be highly sensitive regarding the assessment of clinically relevant stenotic lesions.
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- 2009
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180. [Atrial tumors in cardiac MRI].
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Kraemer N, Balzer JC, Schoth F, Neizel M, Kuehl H, Günther RW, and Krombach G
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- Diagnosis, Differential, Electrocardiography, Fibroma diagnosis, Germany, Heart Neoplasms secondary, Heart Valves pathology, Heart Ventricles pathology, Hemangioma diagnosis, Hemangiosarcoma diagnosis, Humans, Lipoma diagnosis, Lymphoma diagnosis, Myxoma diagnosis, Pericardium pathology, Practice Guidelines as Topic, Rhabdomyoma diagnosis, Rhabdomyosarcoma diagnosis, Sarcoma diagnosis, Thrombosis diagnosis, Heart Atria pathology, Heart Neoplasms diagnosis, Image Enhancement methods, Image Processing, Computer-Assisted methods, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging methods, Magnetic Resonance Imaging, Cine methods
- Abstract
Cardiac magnetic resonance imaging (MRI) is an important tool for the diagnosis of cardiac masses. Various cardiac tumors are predisposed to occurring in atrial structures. The aim of this review article is the description of atrial tumors and their morphological features in MRI. In general, cardiac tumors are rare: approximately 0.001 - 0.03 % in autopsy studies. About 75 % of them are benign. The most common cardiac tumor is the myxoma. They are predisposed to occur in the atria and show a characteristically strong hyperintense signal on T 2-wieghted images in MRI. In other sequences a heterogeneous pattern reflects its variable histological appearance. Lipomas exhibit a signal behavior identical to fatty tissue with a typical passive movement in cine imaging. Fibroelastomas are the most common tumors of the cardiac valves. Consisting of avascular fibrous tissue, they often present with hypointense signal intensities. Thrombi attached to their surface can cause severe emboli even in small tumors. Amongst primary cardiac malignancies, sarcomas are most common and favor the atria. Secondary malignancies of the heart are far more common than primary ones (20 - 40 times). In case of known malignancies, approximately 10 % of patients develop cardiac metastasis at the end of their disease. Lymphogenic metastases favor the pericardium, while hematogenic spread prefers the myocardium. Since they are not real atrial tumors, thrombi and anatomical structures of the atria have to be differentiated from other pathologies.
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- 2009
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181. 3-dimensional echocardiographic assessment of left ventricular dyssynchrony: an alternative viewpoint.
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Monaghan M, Bax J, Franke A, Kamp O, Kuehl H, Nihoyannopoulos P, and Tencate F
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- Artifacts, Humans, Predictive Value of Tests, Reproducibility of Results, Echocardiography, Three-Dimensional, Ventricular Dysfunction, Left diagnostic imaging
- Published
- 2009
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182. Avoidance of proximal endoleak using a hybrid stent graft in arch replacement and descending aorta stenting.
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Tsagakis K, Kamler M, Kuehl H, Kowalczyk W, Tossios P, Thielmann M, Osswald B, Erbel R, Eggebrecht H, and Jakob H
- Subjects
- Adult, Aged, Aortic Dissection diagnostic imaging, Aortic Dissection mortality, Aorta, Thoracic diagnostic imaging, Aortic Aneurysm, Thoracic diagnostic imaging, Aortic Aneurysm, Thoracic mortality, Aortic Rupture diagnostic imaging, Aortic Rupture surgery, Blood Vessel Prosthesis Implantation methods, Feasibility Studies, Female, Follow-Up Studies, Germany, Hospital Mortality, Humans, Male, Middle Aged, Postoperative Complications mortality, Prosthesis Fitting, Thrombosis diagnostic imaging, Aortic Dissection surgery, Aorta, Thoracic surgery, Aortic Aneurysm, Thoracic surgery, Aortography, Blood Vessel Prosthesis, Image Processing, Computer-Assisted, Imaging, Three-Dimensional, Postoperative Complications diagnostic imaging, Postoperative Complications prevention & control, Prosthesis Design, Stents, Tomography, X-Ray Computed
- Abstract
Background: In complex thoracic aortic procedures, proximal repair and antegrade stent grafting of the descending aorta is an emerging technique to achieve one-stage treatment of the thoracic aorta. To overcome problems of proximal endoleak, a hybrid stent graft was designed and used. This study assessed technical feasibility and early results., Methods: From Jan 2005 to May 2008, 41 patients (age, 60 +/- 13 years) comprising 35 aortic dissections (AD) and 6 aortic aneurysms underwent arch replacement and antegrade stent grafting of the descending aorta using the hybrid stent graft. Endoleaks were evaluated by computed tomography (CT) scans. In AD cases, the false lumen (FL) was evaluated with CT volume measurements., Results: Combined arch replacement and antegrade stent grafting was technically successful. One proximal endoleak was observed, which was not related to the hybrid prosthesis (40 of 41, 98%). Three patients died (7%). No paraplegia occurred. Incidence of immediate FL thrombosis was 97% at the proximal and 80% at the distal stent graft level. During follow-up (17 +/- 11 months), complete thrombosis of the perigraft space was 91%. FL volume shrinkage was documented (p < 0.01). No perfusion of the perigraft space was observed in aneurysm cases. Intermediate survival was 33 of 38 (87%)., Conclusions: One-stage repair of complex thoracic aortic disease using a hybrid stent graft can be reliably performed with low hospital mortality. Proximal endoleak can be definitely avoided; in AD, exclusion and ongoing significant shrinkage of the FL can be achieved.
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- 2009
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183. Estimating chimpanzee population size with nest counts: validating methods in Taï National Park.
- Author
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Kouakou CY, Boesch C, and Kuehl H
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- Animals, Conservation of Natural Resources methods, Cote d'Ivoire, Female, Geographic Information Systems, Male, Models, Theoretical, Population Density, Nesting Behavior, Pan troglodytes growth & development
- Abstract
Successful conservation and management of wild animals require reliable estimates of their population size. Ape surveys almost always rely on counts of sleeping nests, as the animals occur at low densities and visibility is low in tropical forests. The reliability of standing-crop nest counts and marked-nest counts, the most widely used methods, has not been tested on populations of known size. Therefore, the answer to the question of which method is more appropriate for surveying chimpanzee population remains problematic and comparisons among sites are difficult. This study aimed to test the validity of these two methods by comparing their estimates to the known population size of three habituated chimpanzee communities in Taï National Park [Boesch et al., Am J Phys Anthropol 130:103-115, 2006; Boesch et al., Am J Primatol 70:519-532, 2008]. In addition to transect surveys, we made observations on nest production rate and nest lifetime. Taï chimpanzees built 1.143 nests per day. The mean nest lifetime of 141 fresh nests was 91.22 days. Estimate precision for the two methods did not differ considerably (difference of coefficient of variation <5%). The estimate of mean nest decay time was more precise (CV=6.46%) when we used covariates (tree species, rainfall, nest height and age) to model nest decay rate, than when we took a simple mean of nest decay times (CV=9.17%). The two survey methods produced point estimates of chimpanzee abundance that were similar and reliable: i.e. for both methods the true chimpanzee abundance was included within the 95% estimate confidence interval. We recommend further research on covariate modeling of nest decay times as one way to improve the precision and to reduce the costs of conducting nest surveys.
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- 2009
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184. Diagnostic accuracy of contrast-enhanced FDG-PET/CT in primary staging of cutaneous malignant melanoma.
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Veit-Haibach P, Vogt FM, Jablonka R, Kuehl H, Bockisch A, Beyer T, Dahmen G, Rosenbaum S, and Antoch G
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Follow-Up Studies, Humans, Male, Melanoma diagnostic imaging, Middle Aged, Neoplasm Metastasis diagnostic imaging, Neoplasm Staging, Positron-Emission Tomography, Sensitivity and Specificity, Skin Neoplasms diagnostic imaging, Time Factors, Tomography, X-Ray Computed, Contrast Media, Fluorodeoxyglucose F18, Melanoma diagnosis, Melanoma pathology, Skin Neoplasms diagnosis, Skin Neoplasms pathology
- Abstract
Purpose: To evaluate the diagnostic accuracy of contrast-enhanced FDG-PET/CT (ce-PET/CT), PET-only, and CT-only in patients with newly diagnosed and resected cutaneous malignant melanoma., Methods: A final group of 56 patients (mean age 62 years, range 23-86 years; 29 women, 27 men) were staged with ce-PET/CT after resection of the primary tumour. Histopathology as well as clinical follow-up (mean 780 days, range 102-1,390 days) served as the standards of reference. Differences between the staging modalities were tested for statistical significance with McNemar's test., Results: All imaging procedures provided low sensitivities in the detection of lymph nodes (sensitivity N-stage: PET/CT and PET-only 38.5%; CT-only 23.1%) and distant metastases (sensitivity M-stage: PET/CT 41.7%, PET-only 33.3%, CT-only 25.0%) in initial staging after resection of the primary tumour. No statistically significant differences were detected between the imaging procedures (p > 0.05). PET/CT resulted in an alteration in further treatment in two patients compared to PET-only and in four patients compared to CT-only., Conclusion: All imaging modalities had a low sensitivity on initial staging of patients with malignant melanoma. Thus, close patient follow-up must be considered mandatory.
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- 2009
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185. Feasibility of real-time magnetic resonance-guided angioplasty and stenting of renal arteries in vitro and in Swine, using a new polyetheretherketone-based magnetic resonance-compatible guidewire.
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Kos S, Huegli R, Hofmann E, Quick HH, Kuehl H, Aker S, Kaiser GM, Borm PJ, Jacob AL, and Bilecen D
- Subjects
- Animals, Benzophenones, Humans, Polymers, Swine, Angioplasty methods, Ketones, Magnetic Resonance Imaging, Interventional methods, Phantoms, Imaging, Polyethylene Glycols, Renal Artery Obstruction surgery, Stents
- Abstract
Objectives: Demonstrate the usability of a new polyetheretherketone (PEEK)-based MR-compatible guidewire for renal artery catheterization, angioplasty, and stenting under MR-guidance using MR-visible markers, in vitro and in vivo., Material and Methods: The new 0.035'' guidewire with fiber-reinforced PEEK core, a soft tip, and a hydrophilic coating was used. Paramagnetic markings were coated on the wire and nonbraided catheters for passive visualization. Bending stiffness of the guidewire was compared with available hydrophilic guidewires (Terumo Glidewire Stiff and Standard). A human aortic silicon phantom and 2 pigs were used. The study was animal care and use approved by the committee. Under MR-guidance, renal arteries were catheterized, balloon angioplasty was performed, and balloon expandable renal artery stents were deployed in vivo. Post mortem autopsy was performed. Guidewire visibility, pushability, steerability, and device-support capabilities of the marked guidewire were qualitatively assessed. Procedure times were recorded., Results: Bending stiffness of the new PEEK-based wire was comparable with Standard Glidewire. In vitro and in vivo guidewire guidance, catheter configuration, renal artery catheterization, and balloon angioplasty were successful. In pigs, stent deployments were successful in both renal arteries. Autopsy revealed acceptable stent positioning. Guidewire visibility through applied markers was acceptable. Steerability, pushability, and device support were good in vitro and in vivo., Conclusions: The PEEK-based guide allows percutaneous MR-guided renal artery angioplasty and stenting with sufficient visibility, good steerability, pushability, and device support.
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- 2009
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186. MR-compatible polyetheretherketone-based guide wire assisting MR-guided stenting of iliac and supraaortic arteries in swine: feasibility study.
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Kos S, Huegli R, Hofmann E, Quick HH, Kuehl H, Aker S, Kaiser GM, Borm PJ, Jacob AL, and Bilecen D
- Subjects
- Angioplasty methods, Animals, Aorta surgery, Benzophenones, Biocompatible Materials, Brachiocephalic Trunk surgery, Cardiac Catheterization instrumentation, Cardiac Catheterization methods, Equipment Design, Female, Iliac Artery surgery, Polymers, Subclavian Artery surgery, Swine, Ketones, Magnetic Resonance Imaging, Interventional methods, Polyethylene Glycols, Stents
- Abstract
The purpose of this study was to demonstrate first magnetic resonance (MR)-guided stenting of iliac and supraaortic arteries using a polyetheretherketone-based (PEEK) MR-compatible guide wire. In vitro and animal experiments were performed in a short magnet wide-bore scanner (1.5 Tesla, Espree, Siemens Healthcare, Erlangen, Germany). For all experiments, a 0.035'' MR-compatible guide wire prototoype was used. This wire had a compound core of PEEK with reinforcing fibres, a soft and atraumatic tip and a hydrophilic coating. For its passive visualization, paramagnetic markings were attached. All experiments were performed through a vascular introducer sheath under MR-guidance. In vitro repetitive selective over the wire catheterizations of either the right carotid artery and the left subclavian artery were performed. In vivo, selective catheterization and over-the-wire stenting of the brachiocephalic trunk and the left subclavian artery were performed. The common iliac arteries were catheterized retrogradely (left) and cross-over (right). Angioplasty and stenting were performed over-the-wire. All procedures were successful. Visibility of the PEEK-based guide-wire was rated good in vitro and acceptable in vivo. Guide wire pushability and endovascular device support were good. The PEEK-based MR-compatible guide wire is well visible and usable under MR-guidance. It supports over-the-wire treatment of iliac arteries and supraaortic arteries.
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- 2009
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187. Preoperative assessment of hilar cholangiocarcinoma by dual-modality PET/CT.
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Li J, Kuehl H, Grabellus F, Müller SP, Radunz S, Antoch G, Nadalin S, Broelsch CE, Gerken G, Paul A, and Kaiser GM
- Subjects
- Bile Duct Neoplasms surgery, Bile Ducts, Intrahepatic pathology, Bile Ducts, Intrahepatic surgery, Cholangiocarcinoma surgery, Female, Fluorodeoxyglucose F18, Humans, Male, Middle Aged, Neoplasm Metastasis diagnosis, Neoplasm Staging, Prospective Studies, Radiopharmaceuticals, Sensitivity and Specificity, Bile Duct Neoplasms pathology, Cholangiocarcinoma pathology, Positron-Emission Tomography, Preoperative Care, Tomography, X-Ray Computed
- Abstract
Background: The purpose of the current study was to evaluate the accuracy of (18)F-FDG PET/CT in staging hilar cholangiocarcinoma., Materials and Methods: From June 2004 to December 2007, patients evaluated for surgical treatment of hilar cholangiocarcinoma were entered into a prospective database. Dual modality (18)F-FDG PET/CT was performed before surgery. The report was reviewed with comparison to the operative and pathological results in each case for tumour-node-metastasis staging., Results: Seventeen patients (6 women, 11 men) of a median age of 62 years were included in the study. Radical tumour resection was performed on seven patients. Ten patients underwent surgical exploration. The sensitivity of PET/CT in detecting primary tumour was found to be 58.8% (25% in T2 tumour, 70% in T3 tumour, 66.7% in T4 tumour). The sensitivity/specificity of PET/CT in detecting lymph node metastasis and distant metastasis were 41.7%/80% and 55.6%/87.5%, respectively. Positive (18)F-FDG uptake in the bile duct was found to be associated with surgical non-resectability (P = 0.05)., Conclusion: Dual-modality PET/CT imaging was found to have a high specificity in detection of lymph node and distant metastasis in hilar cholangiocarcinoma, with a limited value in correct judgement of surgical resectability for tumours in stadium UICC I-III., ((c) 2008 Wiley-Liss, Inc.)
- Published
- 2008
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188. Alarming decline of West African chimpanzees in Côte d'Ivoire.
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Campbell G, Kuehl H, N'Goran Kouamé P, and Boesch C
- Subjects
- Animals, Conservation of Natural Resources, Cote d'Ivoire, Population Density, Pan troglodytes
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- 2008
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189. Pulmonary nodules at risk in patients undergoing liver transplantation for hepatocellular carcinoma.
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Sotiropoulos GC, Kuehl H, Sgourakis G, Molmenti EP, Beckebaum S, Cicinnati VR, Baba HA, Schmitz KJ, Broelsch CE, and Lang H
- Subjects
- Adult, Carcinoma, Hepatocellular secondary, Contraindications, Female, Humans, Liver Neoplasms pathology, Lung Neoplasms secondary, Male, Middle Aged, Tomography, X-Ray Computed, Carcinoma, Hepatocellular surgery, Liver Neoplasms surgery, Liver Transplantation, Lung diagnostic imaging, Lung Neoplasms diagnostic imaging
- Abstract
The aim of this study was to evaluate the accuracy of pretransplant imaging in patients with hepatocellular carcinoma (HCC) considering small pulmonary nodules, and to determine whether preoperatively diagnosed small pulmonary nodules should be considered 'nodules at risk'. We evaluated 10 consecutive liver transplant patients with a diagnosis of HCC and pulmonary nodules detected by preoperative computerized tomography (CT) scanning. Pretransplant CT evaluation of pulmonary nodules showed a 90% accuracy rate. There was only one incorrect reading in the case of a patient, where a metastasis was misdiagnosed as a pulmonary fibroma. Two patients died from multifocal tumor recurrence with pulmonary metastases 17 and 19 months post-transplant. One more patient died 29 months post-transplantation on account of diffuse metastatic prostate carcinoma. Seven patients are currently alive with no evidence of tumor after a median follow-up period of 48 months post-transplantation. Small pulmonary nodules in high-risk HCC patients (low tumor grading, exceeding Milan criteria) may be characterized as nodules at risk, and evaluated very closely prior to listing and during the pre- and post-transplant periods.
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- 2008
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190. Diagnostic yield of computed tomography-guided coaxial core biopsy of undetermined masses in the free retroperitoneal space: single-center experience.
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Stattaus J, Kalkmann J, Kuehl H, Metz KA, Nowrousian MR, Forsting M, and Ladd SC
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- Adult, Age Factors, Aged, Biopsy, Needle adverse effects, Cohort Studies, Contrast Media, Female, Follow-Up Studies, Humans, Male, Middle Aged, Retroperitoneal Neoplasms diagnostic imaging, Retroperitoneal Space diagnostic imaging, Retroperitoneal Space pathology, Retrospective Studies, Risk Assessment, Safety Management, Sensitivity and Specificity, Sex Factors, Biopsy, Needle methods, Radiography, Interventional, Retroperitoneal Neoplasms pathology, Tomography, X-Ray Computed methods
- Abstract
The purpose of this study was to evaluate the diagnostic yield of core biopsy in coaxial technique under guidance of computed tomography (CT) for retroperitoneal masses. We performed a retrospective analysis of CT-guided coaxial core biopsies of undetermined masses in the non-organ-bound retroperitoneal space in 49 patients. In 37 cases a 15-G guidance needle with a 16-G semiautomated core biopsy system, and in 12 cases a 16-G guidance needle with an 18-G biopsy system, was used. All biopsies were technically successful. A small hematoma was seen in one case, but no relevant complication occurred. With the coaxial technique, up to 4 specimens were obtained from each lesion (mean, 2.8). Diagnostic accuracy in differentiation between malignant and benign diseases was 95.9%. A specific histological diagnosis could be established in 39 of 42 malignant lesions (92.9%). Correct subtyping of malignant lymphoma according to the WHO classification was possible in 87.0%. Benign lesions were correctly identified in seven cases, although a specific diagnosis could only be made in conjunction with clinical and radiological information. In conclusion, CT-guided coaxial core biopsy provides safe and accurate diagnosis of retroperitoneal masses. A specific histological diagnosis, which is essential for choosing the appropriate therapy, could be established in most cases of malignancy.
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- 2008
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191. Comparison of FDG-PET, PET/CT and MRI for follow-up of colorectal liver metastases treated with radiofrequency ablation: initial results.
- Author
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Kuehl H, Antoch G, Stergar H, Veit-Haibach P, Rosenbaum-Krumme S, Vogt F, Frilling A, Barkhausen J, and Bockisch A
- Subjects
- Adult, Aged, Contrast Media, Female, Fluorodeoxyglucose F18, Humans, Image Processing, Computer-Assisted, Liver Neoplasms diagnostic imaging, Liver Neoplasms secondary, Magnetic Resonance Imaging methods, Male, Middle Aged, Positron-Emission Tomography methods, Radiopharmaceuticals, Tomography, X-Ray Computed methods, Treatment Outcome, Catheter Ablation methods, Colorectal Neoplasms pathology, Liver Neoplasms diagnosis, Liver Neoplasms surgery
- Abstract
Purpose: Morphologic imaging after radiofrequency ablation (RFA) of liver metastases is hampered by rim-like enhancement in the ablation margin, making the identification of local tumor progression (LTP) difficult. Follow-up with PET/CT is compared to follow-up with PET alone and MRI after RFA., Methods and Materials: Sixteen patients showed 25 FDG-positive colorectal liver metastases in pre-interventional PET/CT. Post-interventional PET/CT was performed 24h after ablation and was repeated after 1, 3 and 6 months and then every 6 months. PET and PET/CT data were compared with MR data sets acquired within 14 days before or after these time points. Either histological proof by biopsy or resection, or a combination of contrast-enhanced CT at fixed time points and clinical data served as a reference., Results: The 25 metastases showed a mean size of 20mm and were treated with 39 RFA sessions. Ten lesions which developed LTP received a second round of RFA; four lesions received three rounds of treatment. The mean follow-up time was 22 months. Seventy-two PET/CT and 57 MR examinations were performed for follow-up. The accuracy and sensitivity for tumor detection was 86% and 76% for PET alone, 91% and 83% for PET/CT and 92% and 75% for MRI, respectively., Conclusions: In comparison to PET alone, PET/CT was significantly better for detecting LTP after RFA. There were no significant differences between MRI and PET/CT. These preliminary results, however, need further verification.
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- 2008
- Full Text
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192. Highly iodinated intravenous contrast material for PET/CT - a feasibility study.
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Heusner TA, Kuehl H, Veit-Haibach P, Hahn S, Boy C, Forsting M, Bockisch A, and Antoch G
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- Adolescent, Adult, Aged, Artifacts, Dose-Response Relationship, Drug, Feasibility Studies, Female, Humans, Iopamidol administration & dosage, Male, Middle Aged, Neoplasm Metastasis diagnostic imaging, Neoplasms surgery, Retrospective Studies, Sensitivity and Specificity, Image Enhancement methods, Image Processing, Computer-Assisted methods, Iopamidol analogs & derivatives, Neoplasms diagnostic imaging, Positron-Emission Tomography methods, Tomography, X-Ray Computed methods, Whole Body Imaging methods
- Abstract
Purpose: Intravenous contrast materials (CM) are of benefit in PET/CT imaging. However, CM may influence tracer quantification and may cause artifacts when using the CT data for PET attenuation correction. The aim of the study was to assess the feasibility of applying a highly concentrated CM (HCCM, 400 mg iodine/ml) in PET/CT in comparison to a lower concentrated CM (LCCM, 300 mg iodine/ml)., Materials and Methods: In 60 whole-body FDG PET/CT scans (30 scans each with HCCM and LCCM), tracer uptake (maximal standardized uptake value - SUVmax) and CT attenuation (Hounsfield Units) were quantified at 16 positions in different vessels and parenchyma. The number of potential PET artifacts was documented. The Mann-Whitney-Wilcoxon Test was performed for statistical assessment (p < 0.05)., Results: HCCM did not cause a significant increase in the SUVmax (p > 0.05) or the number of PET artifacts (p = 0.69) while simultaneously significantly increasing CT attenuation (p = 0.002) as compared to LCCM in 11 / 16 positions., Conclusion: The application of HCCM seems feasible in PET/CT and should be considered in future protocols.
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- 2008
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193. Where there is no PET/CT.
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Kuehl H, Antoch G, Bockisch A, and Forsting M
- Subjects
- Adult, Aged, Contrast Media, Female, Fluorodeoxyglucose F18, Humans, Image Processing, Computer-Assisted, Liver Neoplasms diagnostic imaging, Liver Neoplasms secondary, Magnetic Resonance Imaging methods, Male, Middle Aged, Positron-Emission Tomography methods, Radiopharmaceuticals, Tomography, X-Ray Computed methods, Treatment Outcome, Catheter Ablation methods, Colorectal Neoplasms pathology, Liver Neoplasms diagnosis, Liver Neoplasms surgery
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- 2008
- Full Text
- View/download PDF
194. Impact of whole-body imaging on treatment decision to radio-frequency ablation in patients with malignant liver tumors: comparison of [18F]fluorodeoxyglucose-PET/computed tomography, PET and computed tomography.
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Kuehl H, Rosenbaum-Krumme S, Veit-Haibach P, Stergar H, Forsting M, Bockisch A, and Antoch G
- Subjects
- Adult, Aged, Female, Humans, Male, Middle Aged, Patient Selection, Radiopharmaceuticals, Subtraction Technique, Treatment Outcome, Catheter Ablation methods, Fluorodeoxyglucose F18, Liver Neoplasms diagnosis, Liver Neoplasms surgery, Positron-Emission Tomography methods, Preoperative Care methods, Tomography, X-Ray Computed methods
- Abstract
Objective: The correct staging of patients with malignant liver tumors before radio-frequency ablation (RFA) is mandatory for successful treatment. Our study aimed to compare the influence on decision to perform RFA of whole-body fluorodeoxyglucose (FDG)-PET/computed tomography (CT) with whole-body contrast-enhanced CT (CE-CT) and PET alone., Methods: Fifty-eight patients with known hepatic malignancies (23, liver metastases 35) received FDG-PET/CT before RFA planned with curative intention. CT and PET data were each read separately, PET/CT fusion data were read in consensus afterward by a third reader group. The diagnostic accuracy of CE-CT, PET alone, and PET/CT to identify patients eligible for RFA was compared and the impact on decision was analyzed. The McNemar test with Bonferroni correction was used to test for significant differences., Results: The accuracy and sensitivity to detect correctly intrahepatic and extrahepatic tumor were 94 and 97% for CT, 75 and 54% for PET, and 97 and 95% for PET/CT. The differences between CT and PET, as well as between PET/CT and PET, were statistically significant, but there was no significant difference between PET/CT and CT alone (P>0.65). PET alone, CE-CT, and PET/CT correctly identified 32, 55, and 57 patients, respectively. Again, PET/CT showed no significant advantage over CE-CT. Both imaging methods performed significantly better than PET alone (P<0.0001). Forty-three (74%) of 58 patients underwent RFA with curative intention., Conclusion: Whole-body imaging changed patient management in 26% of the patients planned for curative intended RFA, yet there was no significant difference between CE-CT and PET/CT.
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- 2008
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195. Mid-term outcome of positron emission tomography/computed tomography-assisted radiofrequency ablation in primary and secondary liver tumours--a single-centre experience.
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Kuehl H, Stattaus J, Hertel S, Hunold P, Kaiser G, Bockisch A, and Forsting M
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Humans, Liver Neoplasms diagnostic imaging, Liver Neoplasms pathology, Liver Neoplasms secondary, Male, Middle Aged, Retrospective Studies, Risk Factors, Time Factors, Treatment Outcome, Catheter Ablation, Liver Neoplasms surgery, Positron-Emission Tomography, Tomography, X-Ray Computed
- Abstract
Aims: To determine the mid-term results of percutaneous radiofrequency ablation (RFA) of malignant liver tumours when using FDG-positron emission tomography (FDG-PET)/computed tomography for tumour evaluation and follow-up., Materials and Methods: Between January 2002 and June 2006, 55 patients (mean age 63 years) with 78 liver lesions (39 colorectal metastases, 39 hepatocellular carcinoma [HCC] nodules) were treated with RFA. All patients received PET/computed tomography before intervention. RFA was performed under computed tomography guidance with conscious sedation. Post-interventional PET/computed tomography was carried out in PET-positive patients 24h after the ablation and was repeated at 1, 3 and 6 months and every 6 months after the intervention. PET-negative patients received contrast-enhanced computed tomography at the same time points. The rate of local tumour progression (LTP) and survival rates were assessed for the whole patient population., Results: The 78 lesions (mean size 2.3 cm, range 0.8-5 cm) were treated with 101 consecutive ablation procedures resulting in a technical success rate of 96%. The mean time of follow-up was 25+/-12 months. Thirty-five of 78 tumours (45%) developed LTP. At the end of follow-up, LTP was found in 22 patients (40%), with intra- and extrahepatic recurrence in 11 patients. Twenty-two patients remained free of hepatic tumours. The 1-, 2- and 3-year survival rates were 85, 74 and 58%, respectively. Tumour entity, lesion size and localisation were significant risk factors for LTP., Conclusions: Computed tomography-guided RFA of malignant liver tumours is effective, but shows a high rate of LTP. PET/computed tomography supports RFA by early identification of residual tumour or LTP.
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- 2008
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196. Cervical lymph node metastases of unknown origin: primary tumor detection with whole-body positron emission tomography/computed tomography.
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Nassenstein K, Veit-Haibach P, Stergar H, Gutzeit A, Freudenberg L, Kuehl H, Fischer M, Barkhausen J, Bockisch A, and Antoch G
- Subjects
- Aged, Female, Fluorodeoxyglucose F18, Humans, Male, Middle Aged, Neck, Neoplasms, Unknown Primary pathology, Positron-Emission Tomography, Radiopharmaceuticals, Sensitivity and Specificity, Tomography, X-Ray Computed, Lymphatic Metastasis diagnostic imaging, Neoplasms, Unknown Primary diagnostic imaging
- Abstract
Background: Identification of primary tumor in patients with cervical lymph node metastasis of unknown primary (MUO) has a great impact on therapy approach and potentially on patient prognosis., Purpose: To assess the diagnostic accuracy of combined positron emission tomography(PET)/computer tomography (CT) for primary tumor detection in cervical metastases of unknown origin compared to PET, CT, and PET+CT side-by-side evaluation., Material and Methods: 39 consecutive patients (eight women, 31 men; mean age 59.9 ± 11.2 years) with MUO were enrolled in this study. PET/CT images were obtained 1 hour after injection of 350 MBq of fluorodeoxyglucose. Oral and intravenous contrast agents were administered in all patients to ensure diagnostic CT data. Fused PET/CT data were evaluated for primary tumor detection. Diagnostic accuracy was calculated and compared with CT alone, PET alone, and side-by-side PET+CT evaluation.Statistical analysis of differences in diagnostic performance between the different imaging procedures was based on the McNemar test., Results: Fused PET/CT depicted the primary tumor in 11 of 39 (28%) patients. In 28(72%) patients, the primary tumor remained occult. CT revealed the primary in five(13%), PET alone in 10 (26%), and side-by-side evaluation of PET+CT in 10 (26%) of 39 patients. Statistical analysis showed no significant differences between the imaging modalities., Conclusion: PET, side-by-side PET+CT, and PET/CT revealed similar detection rates for primary tumors in cervical MUO patients. Therefore, cervical metastases of an unknown primary may be assessed with either of these imaging modalities. Detection rates with CT were substantially lower. Thus, inclusion of functional data for assessment of cervical MUO patients must be recommended.
- Published
- 2007
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197. Morphologic and functional changes in nontumorous liver tissue after radiofrequency ablation in an in vivo model: comparison of 18F-FDG PET/CT, MRI, ultrasound, and CT.
- Author
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Vogt FM, Antoch G, Veit P, Freudenberg LS, Blechschmid N, Diersch O, Bockisch A, Barkhausen J, and Kuehl H
- Subjects
- Animals, Liver diagnostic imaging, Liver Neoplasms diagnostic imaging, Liver Neoplasms pathology, Magnetic Resonance Imaging methods, Male, Necrosis, Neoplasm, Residual, Positron-Emission Tomography methods, Radiopharmaceuticals, Swine, Swine, Miniature, Tomography, X-Ray Computed methods, Ultrasonography, Catheter Ablation, Fluorodeoxyglucose F18, Liver pathology
- Abstract
Unlabelled: Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on (18)F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from regenerative tissue after radiofrequency ablation of liver lesions. This study used MRI, CT, ultrasound, and (18)F-FDG PET/CT to assess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation., Methods: Lesions were created by radiofrequency ablation of normal liver parenchyma in 21 minipigs. Follow-up was performed by 3 contrast-enhanced morphologic modalities-MRI, CT, and ultrasound-and by (18)F-FDG PET/CT immediately, 3 and 10 d, and 1, 2, 3, and 6 mo after radiofrequency ablation. Images were evaluated qualitatively for areas of increased enhancement and regions of elevated tracer uptake. Furthermore, all images were assessed quantitatively by determination of ratios comparing enhancement/tracer uptake in the periphery of the necrosis with enhancement/tracer uptake in normal liver parenchyma. Imaging findings were compared with histopathology findings., Results: Immediately after radiofrequency ablation, no increase in (18)F-FDG uptake was visible, whereas elevated enhancement was noticed in the periphery of the necrosis on all morphologic imaging procedures. At further follow-up, an area of rimlike increase in (18)F-FDG uptake surrounding the necrosis was detected on PET/CT. The rimlike pattern of increased enhancement in the arterial phase was present for all liver lesions on CT, MRI, and ultrasound, especially between day 3 and month 1 after the radiofrequency ablation. Both elevated glucose metabolism and enhancement persisted for 6 mo postinterventionally. Histologic examination showed a hemorrhagic border converting into a regeneration capsule., Conclusion: If performed immediately after radiofrequency ablation, (18)F-FDG PET/CT probably has benefits over those of morphologic imaging procedures when assessing liver tissue for residual tumor. Later follow-up may be hampered by visualization of peripheral hyperperfusion and tissue regeneration. Further studies on a patient population are essential.
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- 2007
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198. CT-guided biopsy of small liver lesions: visibility, artifacts, and corresponding diagnostic accuracy.
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Stattaus J, Kuehl H, Ladd S, Schroeder T, Antoch G, Baba HA, Barkhausen J, and Forsting M
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- Adult, Aged, False Negative Reactions, Female, Humans, Liver Neoplasms diagnostic imaging, Liver Neoplasms pathology, Male, Middle Aged, Predictive Value of Tests, Radiographic Image Interpretation, Computer-Assisted, Retrospective Studies, Sensitivity and Specificity, Artifacts, Biopsy, Needle methods, Contrast Media, Iohexol analogs & derivatives, Liver Neoplasms diagnosis, Radiography, Interventional, Tomography, X-Ray Computed
- Abstract
Purpose: Our study aimed to determine the visibility of small liver lesions during CT-guided biopsy and to assess the influence of lesion visibility on biopsy results., Material and Methods: Fifty patients underwent CT-guided core biopsy of small focal liver lesions (maximum diameter, 3 cm); 38 biopsies were performed using noncontrast CT, and the remaining 12 were contrast-enhanced. Visibility of all lesions was graded on a 4-point-scale (0 = not visible, 1 = poorly visible, 2 = sufficiently visible, 3 = excellently visible) before and during biopsy (with the needle placed adjacent to and within the target lesion)., Results: Forty-three biopsies (86%) yielded diagnostic results, and seven biopsies were false-negative. In noncontrast biopsies, the rate of insufficiently visualized lesions (grades 0-1) increased significantly during the procedure, from 10.5% to 44.7%, due to needle artifacts. This resulted in more (17.6%) false-negative biopsy results compared to lesions with good visualization (4.8%), although this difference lacks statistical significance. Visualization impairment appeared more often with an intercostal or subcostal vs. an epigastric access and with a subcapsular vs. a central lesion location, respectively. With contrast-enhanced biopsy the visibility of hepatic lesions was only temporarily improved, with a risk of complete obscuration in the late phase., Conclusion: In conclusion, visibility of small liver lesions diminished significantly during CT-guided biopsy due to needle artifacts, with a fourfold increased rate of insufficiently visualized lesions and of false-negative histological results. Contrast enhancement did not reveal better results.
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- 2007
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199. Anesthesia for cardiovascular interventions and magnetic resonance imaging in pigs.
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Kaiser GM, Breuckmann F, Aker S, Eggebrecht H, Kuehl H, Erbel R, Fruhauf NR, Broelsch CE, and Quick HH
- Subjects
- Anesthesiology instrumentation, Animals, Anesthesia methods, Cardiovascular Surgical Procedures, Laboratory Animal Science methods, Magnetic Resonance Imaging instrumentation, Sus scrofa surgery
- Abstract
Large animal models are still required for many experimental purposes. The aim of the current study was to define a viable narcotic procedure for experimental cardiovascular interventions and imaging in pigs. A total of 32 domestic pigs were used. Animals received propofol, midazolam, and fentanyl as continuous intravenous infusion anesthesia for complex vascular interventions, angiographic X-ray imaging, and magnetic resonance imaging (MRI). Anesthesia was maintained for 6 to 10 h. The initial hourly doses were 2.29 mg/kg of propofol, 1.14 mg/kg of midazolam, and 0.009 mg/kg of fentanyl, with controlled ventilation. Anesthesia, interventions, imaging, periods of apnea of as long as 2 min, and transportation were well-tolerated. Stress-induced arrhythmias were not noted, and artifact-free imaging was achieved. The combination of propofol, midazolam, and fentanyl is well-suited for experimental angiographic interventional studies, experimental cardiovascular MRI, and MR-guided interventions in pigs.
- Published
- 2007
200. Quantification of left ventricular volumes and ejection fraction from 16- and rebinned 8-frame gated 99mTc-tetrofosmin SPECT. Comparison of 4D-MSPECT and QGS.
- Author
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Schaefer WM, Kaiser HJ, Kuehl H, Koch KC, Nowak B, and Buell U
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Heart diagnostic imaging, Humans, Male, Middle Aged, Organophosphorus Compounds, Organotechnetium Compounds, Radiopharmaceuticals, Regression Analysis, Reproducibility of Results, Tomography, Emission-Computed, Single-Photon methods, Heart Ventricles diagnostic imaging, Ventricular Function, Left
- Abstract
Aim: Using 8-frames/cardiac cycle with gated SPECT underestimates end-diastolic volumes (EDV) and ejection fractions (LVEF), and overestimates end-systolic volumes (ESV). However, using 16-frames/cardiac cycle significantly decreases the signal-to-noise-ratio. We analyzed 16-frames and rebinned 8-frame gated SPECT data using common 4D-MSPECT and QGS algorithms., Patients, Methods: 120 patients were examined using gated SPECT on a Siemens Multispect 3 (triple-head gamma camera) 60 minutes after intravenous administration at rest of about 450 MBq (two-day protocol) or about 750 MBq (one-day protocol) (99m)Tc-tetrofosmin. Reoriented short axis slices (16-frames) were summed framewise (1+2,3+4, etc.) yielding 8-frame data sets. EDV, ESV and LVEF were calculated for both data sets using 4D-MSPECT and QGS., Results: QGS succeeded with 119, 4D-MSPECT with 117 patients. For the remaining 116 patients, higher EDV (+0.8ml/+3.8 ml) and LVEF (+1.5%/+2.6%; absolute) and lower ESV (-1.7ml/-0.9 ml) (4D-MSPECT/QGS) were found for 16-frame runs. Bland-Altman limits were smaller for QGS than 4D-MSPECT [EDV 32/12 ml, ESV 21/10 ml, LVEF 17/7% (4D-MSPECT/QGS)]., Conclusion: Both algorithms showed the expected effects. Contour finding using QGS failed with only one data set, whereas contour finding using 4D-MSPECT failed with three data sets. Since the effects observed between the 8- and the 16-frame studies are relatively small and quite predictable, 8-frame studies can be employed in clinical routine with hardly any loss at all, plus contour finding appears less susceptible to error.
- Published
- 2007
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