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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of noninvasive electrocardiology 2 (1997), S. 0 
    ISSN: 1542-474X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective: Criteria for detection of late potentials have not yet been standardized, but the criteria recommended by ESC/AHA/ACC are widely used. In this investigation, the prevalence of late potentials is studied in an age stratified healthy population with likelihood of coronary artery disease 〈 5%. Relation between signal-averaged variables and clinical variables was studied.Methods: Signal-averaged ECGs were recorded using Butterworth filters at 40 and 250 Hz. The following three time-domain parameters were evaluated: QRS duration (duration of the amplified, filtered QRS complex); LPD (duration of the late potentials, i.e., duration from the point of time when the magnitude of the main complex becomes lower than 40 μV); and RMS40 (root mean square of the activity within the last 40 ms of the amplified, filtered QRS complex).Results: QRS duration was significantly longer in men than in women, and was correlated to the mass of the left ventricle (LVM). The combination LPD and RMS40 gave the highest prevalence of late potentials. The prevalence of late potentials was 25%.Conclusion: Standard criteria should be used with great caution, and normal limits should be established in each laboratory to a preselected noise level. QRSD should be included within the definition of reference limits and should be gender matched. Even though there is correlation between LVM and the QRSD, the upper normal limit of QRSD based on LVM matching is unchanged.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1619-7089
    Keywords: Bull's eye ; Myocardial single-photon emission tomography ; Reference data base ; Technetium-99m sestamibi ; Technetium-99m tetrofosmin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to compare technetium-99m labelled tetrofosmin and sestamibi myocardial perfusion single-photon emission tomography (SPET) with one common sestamibi reference file for bull's eye imaging, with quantitation of the extent and severity of perfusion defects. Twenty patients suspected or known to have coronary artery disease participated in the study. Patients first underwent routine sestamibi myocardial SPET over 2 days, receiving doses of 400–600 MBq at stress and 600–800 MBq at rest. Then within the same week a 1-day tetrofosmin myocardial SPET study was performed, with a dose of 300 MBq at stress, followed 2.5 h later by a dose of 750 MBq at rest. Bull's eye images were generated for visual evaluation. Black-out defects according to the Cequal software analysis were only recorded if they comprised more than 10 pixels in men and 20 in women. According to the Cequal program, extent score and severity scores were expressed as number of pixels and deviations below reference limits. Five patients had normal myocardial SPET imaging with both radiotracers, while 15 had reversible, irreversible or partially reversible defects. The concordance of the results was high. The only two significant differences were that one patient had a reversible defect which appeared to be located in different myocardial regions (LAD vs RCA), and another patient had a defect that was partially reversible with sestamibi but irreversible with tetrofosmin. The results showed very high correlation coefficients for the extent and severity scores (linear correlation coefficient values of 0.99 and 0.94, respectively). In conclusion, it appears that changing between sestamibi and tetrofosmin has little influence on the interpretation of bull's eye images from the data file of a common reference population using one of the tracers.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1619-7089
    Keywords: Immunoscintigraphy ; Tissue plasminogen activator ; Radiolabelled antibody ; Venous thrombosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The administration of a radiolabelled monoclonal antibody against tissue plasminogen activator allows detection of areas with increased fibrinolytic activity, i. e. those with an active thrombotic lesion. Eight patients with phlebographically verified deep venous thrombosis were examined. At the time of immunoscintigraphy study they were examined receiving anticoagulant therapy. Some 75–85 MBq indium 111-labelled antibody were injected, and scintigrams were obtained after 30 min and after 24 h. The precise site of the thrombus could not be visualized after 30 min due to high background activity, whereas after 24 h it was detectable in all patients. The thrombus/background ratios achieved are twice as high as those observed in a human antifibrin antibody study. These preliminary data suggest a high sensitivity of our t-PA-specific antibody for the detection of active deep venous thrombosis in man, and our antibody seems to offer theoretical advantages over both platelet and fibrin-specific antibodies.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nuclear medicine 24 (1997), S. 179-183 
    ISSN: 1619-7089
    Keywords: Technetium-99m sestamibi ; Coronary artery disease ; Reference databases ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Myocardial perfusion single-photon emission tomographic (SPET) imaging has been shown to be sensitive in the detection of coronary artery disease (CAD), whereas its specificity has been suboptimal. The aim of the present study was to study the frequency of abnormal bull's eye perfusion defects in a large age-stratified group of healthy subjects undergoing myocardial SPET assessed by comparison with two existing commercially available reference databases. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a less than 5% likelihood of CAD underwent rest and exercise technetium-99m sestamibi SPET. The false-positive response rate, defined as a significant reversible defect, was 12% when compared to the CEqual database and 29% when compared to the Cedars-Sinai database. With the CEqual program, rest defects occurred in 12% of the subjects. Defects occurred more often in women than in men, but the difference did not attain statistical significance. Significant defects were most frequent in the inferior wall and in women in the anterior wall as well. The distribution of defects was independent of age. Our results suggest that the specificity of99mTc-sestamibi myocardial SPET using commercially available reference files is suboptimal. The risk of obtaining a falsepositive test result in subjects undergoing99mTc-sestamibi myocardial SPET with a very low likelihood of CAD was higher than anticipated. With both reference files false-positive test results were most frequently observed in the inferior wall. Our data suggest that commercial reference files for myocardial SPET need to be optimised, and should be used with caution. The use of attenuation correction may prove to be a major step forward.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1619-7089
    Keywords: Myocardial single-photon emission tomography ; Reference limits ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise99mTc-sestamibi SPET with a 2-day protocol and 180° elliptical rotation. The normalized activity values of99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1619-7089
    Keywords: Key words: Myocardial single-photon emission tomography ; Left ventricular hypertrophy ; Athletes ; Cardiac imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Exercise ECG and myocardial single-photon emission tomography (SPET) are fundamental in the non-invasive evaluation of patients suspected of having coronary artery disease (CAD). The purpose of the present study was to investigate the influence of physiological left ventricular hypertrophy (LVH) on myocardial sestamibi SPET in healthy young and old athletes. Eighteen young male elite athletes (ten rowers, five power/weight lifters and three triathletes) and 14 well-trained elderly rowers were studied. All underwent a bicycle test as part of a 2-day sestamibi SPET protocol. Attenuation correction was not performed. The studies were evaluated visually and quantitatively analysed by the CEqual program with its reference files and with a file from a local non-athletic age-matched population. Echocardiographic LVH was an inclusion criterion in the young athletes. Exercise ECG was normal in all subjects. In at least three of the young athletes a reversible defect was observed by visual analysis. On quantitative analysis one-third of the young athletes had ”significant” (〉10 pixels) defects compared with both the local reference base and the CEqual reference population. Nearly all defects were found in the anterior or inferior wall. The remaining subjects, including all old rowers, had normal SPET findings. Anterior and inferior wall defects are so common in healthy athletes with physiological LVH that the specificity of myocardial SPET, in contrast to exercise ECG, seems to be too low for evaluation of chest pain in this group. The mechanism of anterior and inferior defects may be related to hot spots (papillary muscles?) in the lateral wall. The specificity of SPET is maintained in athletes without LVH.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1619-7089
    Keywords: Key words: Myocardial single-photon emission tomography ; Reference limits ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise 99mTc-sestamibi SPET with a 2-day protocol and 180° elliptical rotation. The normalized activity values of 99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in 99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-0743
    Keywords: myocardial viability ; PET ; SPECT ; dobutamine echocardiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. Myocardial segments with impaired function may have the potential for functional recovery. Augmented exogenous glucose uptake in relation to blood flow estimated by [2-18F]2-fluorodeoxyglucose (FDG) and positron emission tomography (PET) frequently indicates functional reversibility. The spectrum of FDG uptake levels in relation to Sestamibi uptake and dobutamine contraction reserve in areas with impaired function subtended by an occluded coronary artery has never been reported. Methods and results. Seventeen patients with stable angina pectoris and dysfunctional myocardium subtended by an occluded coronary artery were studied with FDG-PET, low-dose dobutamine echocardiography and Sestamibi - Single Photon Emission Computerized Tomography. In a 16 segment model dysfunctional myocardial segments showed a normally distributed FDG uptake ranging from 34% to 150% when normalized to peak segmental Sestamibi uptake. Low FDG uptake was associated with both lack of dobutamine induced contractile reserve and low Sestamibi uptake (in 73% of the segments) whereas high FDG uptake displayed both contractile reserve and Sestamibi uptake (57%). Segments with intermediate FDG uptake had either contractile reserve or a preserved Sestamibi uptake (62%). Conclusion. Dysfunctional myocardium subtended by an occluded coronary artery represents a continuum of metabolic states with a high degree of heterogeneity with regard to contractile reserve and Sestamibi uptake.
    Type of Medium: Electronic Resource
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