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Photon Emission Tomography (photon + emission_tomography)

Distribution by Scientific Domains
Medical Sciences85%

Kinds of Photon Emission Tomography

  • single photon emission tomography
    		•

    Selected Abstracts

    Assessment of Myocardial Viability with Dobutamine Stress Echocardiography in Patients with Ischemic Left Ventricular Dysfunction

    ECHOCARDIOGRAPHY, Issue 1 2005
    Siu-Sun Yao M.D.
    The noninvasive assessment of myocardial viability has proved clinically useful for distinguishing hibernating and/or stunned myocardium from irreversibly injured myocardium in patients with chronic ischemic heart disease or recent myocardial infarction, with marked regional and/or global left ventricular (LV) dysfunction. Noninvasive techniques utilized for the detection of viability in asynergic myocardial regions include positron emission tomographic imaging of residual metabolic activity, single photon emission tomography (SPECT) of radioisotope uptake with thallium-201, low-dose dobutamine echocardiography assessment of inotropic reserve and myocardial contrast echocardiography for evaluation of microvascular integrity. Of these techniques, dobutamine stress echocardiography is a safe, widely available and relatively inexpensive modality for the identification of myocardial viability for risk stratification and prognosis. Low-dose dobutamine response can accurately predict improvement of dysfunctional yet viable myocardial regions, and thus identify a subset of patients whose LV function will improve following successful coronary revascularization. [source]

    Levels of ,-Aminobutyric Acid-Benzodiazepine Receptors in Abstinent, Alcohol-Dependent Women: Preliminary Findings From an 123I-Iomazenil Single Photon Emission Tomography Study

    ALCOHOLISM, Issue 9 2000
    A. R. Lingford-Hughes
    Background: Although alcohol dependence in women is an increasing problem, little is known about the effects of alcohol on the female brain. Evidence from a few structural and functional neuroimaging studies suggests that the female brain may be more susceptible than the male brain to the harmful effects of alcohol. However, no in vivo studies of the neuropharmacology of alcohol dependence in women have been carried out. The aim of this preliminary study was to test the hypothesis that alcohol dependence in women is associated with greater reduction in ,-aminobutyric acid (GABA)-benzodiazepine receptor levels than in men with an equivalent drinking history. Methods: We used single photon emission tomography and 123I-iomazenil to label the central GABA-benzodiazepine receptor and to compare semiquantified levels in 9 abstinent alcohol-dependent and 13 control women. These groups were further compared with equivalent male groups from a previous study. Results: There was a trend toward a reduction in GABA-benzodiazepine receptor levels in alcohol-dependent women, but this did not reach significance. These lower levels were seen primarily in the cerebellum, occipital lobes, and parietal cortex (left > right). This was in marked contrast with the pattern of reduction seen in the previous study of male dependence, where significant reductions were seen primarily in the frontal cortex. Conclusions: Due to the semiquantitative analysis performed and the relatively small number of subjects in this study, which resulted in a nonsignificant trend, we can only comment on the differences in the pattern of lower levels of GABA-benzodiazepine receptors seen in alcohol dependence in men and women. Although we are not able to ascertain whether the female brain is more susceptible to the effects of alcohol, it appears that alcohol has a differential effect on the central GABA-benzodiazepine receptors in men and women. Recent animal evidence supports this hypothesis. Future studies should explore whether other neuropharmacological differences exist between men and women in alcohol dependence that could have implications for pharmacotherapy. [source]

    Parkinson's disease: 10 years of progress, 1997,2007,,

    MOVEMENT DISORDERS, Issue S1 2010
    Stanley Fahn MD
    Abstract Many people with Parkinson's disease (PD) and their family members ask their physicians "What is happening in research on Parkinson's disease? Is there anything new?" As the initial speaker at the symposium organized by the Parkinson's Disease Foundation in celebration of its 50th anniversary, I sought to address these questions, focusing on research published between the years 1997 and 2007. I cataloged the advances I considered most important in the field, recognizing my viewpoint is a subjective one and most likely differs from similar listings that others would put together. Space limitation allows me to discuss only a tiny fraction of the remarkable new findings that have been discovered during this 10-year span. Nevertheless, I expect the readers of this summation of advances in the field to be as impressed as I am on the wealth, breadth, and excitement stirring in the field of PD research. Included in this overview are highlights in both laboratory science and clinical science of PD research. In the former category are advances in knowledge on the genetics of PD; potential etiologic and pathogenic causes, especially the better understanding of endogenous factors within dopaminergic neurons; pathologic changes including deposition of alpha-synuclein aggregates; and the consequences of altered alpha-synuclein on the degradation of proteins by both the ubiquitin-proteasomal pathway and the lysosome. Clinical science has also been very active and impressively productive with important clinical advances. In this category are new information on the epidemiology of PD, including awareness of additional factors (besides smoking) that might slow the onset and worsening of PD, such as caffeine and urate; neuroimaging with positron emission tomography and single photon emission tomography; keener awareness of nonmotor features of PD and their impact on quality of life for the persons with PD and their family; recognition of behavioral complications of medications utilized to treat PD, such as impulse control problems; appreciation of the natural history of PD with the increasing impairments as the disease relentlessly worsens over time; the many controlled clinical trials attempting to slow the progression of the disease and to provide new symptomatic therapies; and surgical approaches to alleviate symptoms and progression, including cellular and gene therapy as well as deep brain stimulation. © 2010 Movement Disorder Society [source]

    Senile chorea treated by deep brain stimulation,A clinical, neurophysiological and functional imaging study,

    MOVEMENT DISORDERS, Issue 5 2004
    John Yianni MRCS
    Abstract We report on a patient with senile chorea, treated with deep brain stimulation of the left globus pallidus internus and subsequently the left ventralis oralis posterior nucleus of the thalamus. Deep brain field potential recordings and functional imaging using single photon emission tomography enabled us to suggest pathophysiological mechanisms for the symptoms. © 2004 Movement Disorder Society [source]

    SPECT and Alzheimer's Disease

    PSYCHOGERIATRICS, Issue 2 2002
    Siobhan Ni Bhriain
    Abstract: This article is review of the role of single photon emission tomography (SPECT) in the diagnosis and management of Alzheimer's disease (AD). It begins by describing AD in terms of diagnosis, pathology and current pharmacological treatment. The relevance of the pathological changes in relation to SPECT is outlined. This is discussed in terms of receptor abnormalities and atrophic changes which in turn effect cerebral blood flow. A detailed description of SPECT methodology describes how the quality of the image is effected by SPECT instrumentation, image reconstruction techniques and a number of subject factors. The article goes on to discuss the role SPECT in the diagnosis of AD and its potential for facilitating early diagnosis. The main focus here is on the changes which occur in cerebral blood flow in AD and the sensitivity and specificity of regional changes in cerebral blood flow is described. Image analysis is an area in which there has been many developments in the last number of years and the authors describe the differences between qualitative and quantitative image analysis, with a particular focus on statistical parametric mapping (SPM). There is a brief discussion concerning receptor ligands and their potential use in the diagnosis and management of AD, although this remains an undeveloped area in SPECT imaging as yet. Finally, the authors discuss the future possibilities for SPECT and AD, and conclude that there is considerable potential for SPECT in the diagnosis and management of AD with further refinement of image analysis techniques and the development of cholinergic receptor ligands. [source]

    Diagnostic imaging tests and microbial infections

    CELLULAR MICROBIOLOGY, Issue 10 2007
    Christopher J. Palestro
    Summary Despite significant advances in the understanding of its pathogenesis, infection remains a major cause of patient morbidity and mortality. While the presence of infection may be suggested by signs and symptoms, imaging tests are often used to localize or confirm its presence. There are two principal imaging test types: morphological and functional. Morphological tests include radiographs, computed tomography (CT), magnetic resonance imaging, and sonongraphy. These procedures detect anatomic, or structural, alterations produced by microbial invasion and host response. Functional imaging tests reflect the physiological changes that are part of this process. Prototypical functional tests are radionuclide procedures such as bone, gallium, labelled leukocyte and fluorodeoxyglucose (FDG)-positron emission tomography (PET) imaging. In-line functional/morphological tomographic imaging systems, PET/CT and single photon emission tomography (SPECT)/CT, have revolutionized diagnostic imaging. These devices consist of a functional imaging device (PET or SPECT) joined together with a CT scanner. The patient undergoes both tests sequentially without leaving the examination table. Images from each study can be viewed separately and as fused images, providing precisely localized anatomic and functional information. It must be noted, however, that none of the current morphological or functional tests, either alone or in combination, are specific for infection and the goal of finding such an imaging test remains elusive. [source]

    Regulation of cerebral blood flow in patients with autonomic dysfunction and severe postural hypotension

    CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 4 2002
    Birger Hesse
    Background:,Whether cerebral blood flow (CBF) autoregulation is maintained in autonomic dysfunction has been debated for a long time, and the rather sparse data available are equivocal. The relationship between CBF and mean arterial blood pressure (MABP) was therefore tested in eight patients with symptoms and signs of severe cardiovascular autonomic dysfunction. Patients and methods:,Eight patients were included, three of whom had Parkinson's disease, three diabetes, one pure autonomic failure and the last one had multiple system atrophy. By the use of two techniques, the arteriovenous oxygen [(a-v)O2] method and xenon-inhalation with single photon emission tomography, 15 measurements (range 10,20) and three to four CBF measurements, respectively, were obtained in each patient. Following CBF measurements during baseline, MABP was raised gradually using intravenous noradrenaline infusion, and then lowered by application of lower body negative pressure. From the (a-v)O2 samples the CBF response to changes in MABP was evaluated using a computer program fitting one or two regression lines through the plot. Results and conclusion:,Preserved autoregulation was observed in three patients, while the remaining five patients showed a linear relationship between CBF and MABP. Comparison of the results of the tomographic CBF measurements to the (a-v)O2 data demonstrated that it is not possible to assess whether CBF is autoregulated or not with only three to four pairs of data. [source]