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  • 1
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Nuclear Instruments and Methods 51 (1967), S. 241-244 
    ISSN: 0029-554X
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Energietechnik , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Lung 141 (1969), S. 139-147 
    ISSN: 1432-1750
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1619-7089
    Schlagwort(e): Contraction fraction ; 99mTc-MIBI ; SPECT ; Myocardial size ; Radionuclide ventriculography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Criteria for the detection of coronary artery disease in nuclear cardiology include visualization of perfusion defects and functional impairment of contraction. The purpose of this study is to combine both methods in one procedure with the new myocardial perfusion tracer, 99mTc-methoxy-isobutyl-isonitril (MIBI), reducing time and radiation burden to the patient. Following an uncomplicated recovery, ten patients with first myocardial infarction participated in this study. Radionuclide ventriculography (RNV) was performed at rest and during exercise. Within 2–3 days, 370 MBq 99mTc-MIBI were injected and SPECT acquisition commenced 1 h later. Data processing included a scar image in polar coordinates. Areas of significantly reduced tracer uptake were expressed as a percentage of the total myocardial area. Directly following SPECT, resting and maximum exercise gated planar LAO images were recorded and the contraction was quantified. The concept of the contraction fraction (CF) rested on the end systolic change in count distribution: their increase in density and their centripetal concentration. For comparison, geometrical inner edge detection techniques were also applied. All algorithms for describing an EF equivalent were verified by computer simulations, showing a perfect correlation over a wide range of preset EFs. When applied to the patient studies only the non geometric methods revealed a good correlation with the ejection fraction (EF) obtained by RNV, and with the infarct size measured by SPECT. The corresponding correlation coefficients (r), standard errors (SEE) and the regression lines read as follows (in %): CF=0.56×EF+24.8; r=0.87; SEE=4.98; CF=-0.53×SPECT+71.5; r=0.93; SEE=4.19. Thus, estimation of the left ventricular function by the above defined CF is feasible, easy to perform and clinically meaningful. In one procedure with 99mTc-labelled MIBI not only the perfusion abnormalities were detectable, but also any reduction in function by a valied EF equivalent. Although the monochromatic gamma spectrum of the radionuclide provided better tissue penetrating power, the inner edge of the left ventricle was poorly outlined (especially in the stress studies) and does not lend itself to clinical routine practice.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1619-7089
    Schlagwort(e): Radionuclide ventriculography ; Myocardial scanning ; Functional imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Myocardial scanning (MS) and radionuclide ventriculography (RNV) are the foundation of nuclear cardiology. These procedures aim in two completely different directions: RNV tries to image heart motion, that is, mechanical (pump) function, and therefore belongs to the group of first-order functional imaging (FI, imaging mechanical function), whereas MS is based on myocardial metabolism, and therefore can be attributed to third-order functional imaging (metabolism). This statement is relevant for the assessment of the clinical position of RNV: Third-order (metabolism) functional imaging is the domain of nuclear medicine (NM), whereas first-order FI has to face the competition of alternative noninvasive procedures such as ultrasound (US), digital subtraction angiography (DSA), computer tomography (CT), and nuclear magnetic resonance (NMR). The domain of RNV includes stages two (acute infarction) and three (postinfarction period) of coronary arterial disease (CAD). The advantageous combination of quantitative data on global, left ventricular (LV) function and imaging of regional motion ensures the superiority of RNV over US. However, RNV is inferior to MS in physical examinations in the preinfarction stage of CAD, whereas US is clearly inferior to both NM procedures. Recent progress could be attained by gated SPECT (GASPECT). A proposal is presented for simplification of this time-consuming procedure. Technetium-labeled isonitriles offer the chance for the combination of “perfusion-motion” imaging of the myocardium. However, even standard RNV offers new possibilities. The multitude of parameters produced by quantitation has not yet been exploited completely. This can be done by discriminant analysis. The computer finds out an optimal subset from the whole set of parameters for the solution of a significant clinical problem. The software “learns” to find the “label” of a special pathognomonic entity. This computer work is supported by a relational data bank (Oracle) and an optical disk. Two examples for the effectiveness of the computer in problem solving are presented. It is concluded that RNV, even in the very competitive class of first-order functional imaging, enjoys a preferred position. The future indeed seems brighter because labeled isonitriles offer the chance for the combination of perfusion-motion imaging of the myocardium.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1619-7089
    Schlagwort(e): WPW syndrome ; Location of accessory bypass tract ; Radionuclide ventriculograms ; Fourier phase analysis ; Comparison to ECGs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract It has been suggested that phase analysis of radionuclide ventriculograms may be of value for detecting and localising the abnormal sequence of ventricular contraction secondary to Wolff-Parkinson-White (WPW) syndrome. The present study was undertaken to test this hypothesis. The space-time sequences of right- and left-ventricular action obtained from radionuclide ventriculograms obtained during rest studies were evaluated in 8 patients with WPW syndrome (confirmed by 12-lead surface electrocardiography) and compared to those of 14 normal subjects. All of the latter showed a consistent ventricular activation pattern, i.e. the first site of ventricular activity in the upper septal region followed by a second site either at the base of the left ventricle or located apically. It was possible to diagnose 11 of the 14 normal subjects (specificity, 79%) and 7 of the 8 patients (sensitivity, 88%). The 4 patients who had been classified as having a left-sided accessory bundle by surface electrocardiography were likewise diagnosed by phase analysis, as were the 2 patients with a confirmed right-sided bypass tract. Two patients with septal posterior accessory pathways could not be identified by phase analysis. Furthermore, cases with an activation pattern which closely resembled that of the 2 patients with right-sided accessory bundles were found to be normal from their ECGs. It is now necessary to evaluate phase analysis against invasive electrophysiological methods in such patients.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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