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  • 1
    Digitale Medien
    Digitale Medien
    Should imaging at stress always be followed by imaging at rest in Tc-99m MIBI SPECT? (1997)
    Springer
    The international journal of cardiovascular imaging 13 (1997), S. 323-329 
    Details
    ISSN: 1573-0743
    Schlagwort(e): Technetium-99m MIBI imaging ; myocardial scintigraphy ; myocardial perfusion ; myocardial infarction ; exercise electrocardiography ; imaging strategy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objectives. We addressed the question whether in patients with cardiac chest pain referred for stress myocardial perfusion scintigraphy, Tc-99m MIBI SPECT stress imaging should always be followed by a rest imaging procedure. Background. Using Tc-99m MIBI imaging a stress-rest sequence is usually performed implying that the resting study always follows the stress study irrespective of the results of the stress study. As a normal stress study would eliminate a subsequent resting study, it appears desirable to potentially define certain subsets of patients in whom a normal stress study can be expected in order to determine a more selective referral approach to the nuclear medicine department. The consequences of such a more streamlined approach would less impose on the logistics of the department of nuclear medicine, with decrease of investigation time, radiation dose, and costs in a time of retrenchment in the medical sector. Methods. A consecutive series of 460 patients (mean age 58.2 years) was studied who were stratified to 269 patients without prior myocardial infarction, and to 191 patients with documented evidence of a previously sustained mycoardial infarction. All patients underwent Tc-99m MIBI SPECT imaging according to a two-day stress-rest protocol. Results. Patients with and without a previous myocardial infarction showed suboptimal overall predictive accuracies for the exercise electrocardiograms (58% and 60%, respectively). In the total group of 460 patients, 94 (20%) patients showed a normal stress-rest Tc-99m MIBI SPECT; this occurred in 86/269 (32%) patients without a previous myocardial infarction and in only 8/191 (4%) patients with a previous myocardial infarction. Conclusions. Patients with a stress defect at Tc-99m MIBI SPECT imaging should always undergo a resting SPECT study irrespective of the clinical and stress electrocardiographic findings. As patients without a previous myocardial infarction had a normal stress SPECT study in almost one-third (32%) of patients compared to only 4% in patients with a previous myocardial infarction, it may be useful to employ different referral and imaging strategies i.e. a stress-only versus a stress-rest procedure. To schedule referring patients differently according to the presence or absence of a previously sustained myocardial infarction may be cost-saving, less demanding for the nuclear medicine personnel, and patient-convenient. In addition, a stress-only imaging procedure reduces radiation exposure to the individual patient.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005767823114
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  • 2
    Digitale Medien
    Digitale Medien
    Assessment of left ventricular volume and mass by cine magnetic resonance imaging in patients with anterior myocardial infarction intra-observer and inter-observer variability on contour detection (1996)
    Springer
    The international journal of cardiovascular imaging 12 (1996), S. 11-19 
    Details
    ISSN: 1573-0743
    Schlagwort(e): image processing ; left ventricle ; left ventricular mass ; left ventricular volume ; magnetic resonance imaging ; myocardial infarction ; observer variability ; remodeling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Remodeling of the left ventricle after myocardial infarction can be documented by calculation of left ventricular volume and mass, using endocardial and epicardial tracings of multilevel multiphase short-axis cine magnetic resonance (MR) imaging series. We assessed left ventricular volume and mass from 8 slices and during 12 phases of the cardiac cycle in seven patients with an anterior wall myocardial infarction; one patient was studied twice, leaving eight MR examinations to be evaluated. Purpose of this study was to assess the intra-observer and interobserver variability of epicardial volume, endocardial volume, and left ventricular mass from contours manually traced by two independent observers. For the eight MR examinations, epicardial volume was found to be 292 ± 51 ml (mean ± SD) at end-diastole, which decreased to 237 ± 55 ml at end-systole. Endocardial volume was 141 ± 31 ml at end-diastole, which decreased to 79 ± 27 ml at end-systole. Left ventricular ejection fraction was 45 ± 8%. Mean left ventricular mass, when averaged over all patient studies and all phases, was 159 ± 30 g. Intra-observer and inter-observer variability were found to be 3.5% and 5.2% for endocardial volume, 2.0% and 2.5% for epicardial volume, and 3.6% and 3.6% for left ventricular mass, respectively. The contour analysis showed a statistically significant phase effect in the endocardial contour in the midventricular slices, which was resolved after establishing a more precise definition for the tracing of the endocardial border. In conclusion, left ventricular volume and mass in patients with an anterior wall myocardial infarction can be assessed with high reproducibility and relibility from manual contour tracings. A precise protocol for the definition of endocardial and epicardial contours is required to obtain reproducible and reliable results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01798113
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  • 3
    Digitale Medien
    Digitale Medien
    Regional myocardial shape alterations in patients with anterior myocardial infarction (1996)
    Springer
    The international journal of cardiovascular imaging 12 (1996), S. 89-96 
    Details
    ISSN: 1573-0743
    Schlagwort(e): myocardial infarction ; curvature analysis ; remodelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objective: To assess the impact of regional left ventricular curvature in patients with an acute anterior myocardial infarction on ventricular volume.Methods: Left ventricular curvature was calculated at 100 points from apical four chamber echocardiograms of 68 patients with an acute anterior wall infarction. Curvature at any point of the contour was defined as the reciprocal of the radius of the circle that intersects that point tangentially and was independent of volume and geometric assumptions. Curvature, volume and shape of the patient group was compared with these measurements in 20 normal volunteers.Results: Diastolic curvature differed at the borderzone of the infarct and the apical area. In the basal septal area (point 9–18) mean curvature was lower in the patient group (0.1±2.7 versus 2.1±0.7; p〈0.0001) as compared to the normal individuals. In the mid-septal area (point 22 to 27), mean curvature was more concave (− 0.1±2.6) in the patient group corresponding to in the normal population (− 0.4±1.3) p〈0.005. In the apex point 52 and 53 diverged with a curvature of 9.9±1.9 in patients versus 9.4±2.9 p〈0.005 in normal individuals. Systolic curvature diverged at the basal septum (point 1–4) with a mean curvature of 1.4±1.1 in patients compared to 3.5±2.5 in normal individuals p〈0.01. Curvature differed also in the mid-septal region (point 9–29) with a curvature of − 1.7±1.2 in patients versus 0.4±0.9 (p〈0.01) in normal individuals and in the apical septum (point 48–52) with a curvature of 16.6±5.2 in patients and 13.9±2.6 (p〈0.0001) in healthy individuals. Separation of patients with the greatest curvature alteration to those with minor curvature change revealed, that baseline curvature analysis can discriminate patients at risk for left ventricular remodelling.Conclusion: Regional curvature analysis correctly identifies the geometric changes induced by myocardial infarction. Apical systolic curvature can distinguish those patients that are at risk for left ventricular remodelling from those who are not at risk.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01880739
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