81 results on '"Helber U"'
Search Results
2. Primary systemic amyloidosis leading to advanced renal and cardiac involvement in a 30-year old man
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Spyridopoulos, I., Helber, U., Voelker, W., Huppert, P.E., Gärtner, H.V., Saal, J.G., Hoffmeister, H.M., and Risler, T.
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- 1994
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3. Age-dependency in molecular markers of haemostasis, fibrinolysis and in soluble adhesion molecules
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Szabo, S., Kastner, C., Büttcher, E., Ehlers, R., Kazmaier, S., Helber, U., Pfohl, M., and Hoffmeister, H.M.
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- 2000
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4. Influence of ACE Inhibition on Myocardial Damage, the Kallikrein-Kinin System and Hemostasis during Cardiopulmonary Bypass Surgery
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Heller W, Thomas Walter, Hans Martin Hoffmeister, Bail D, and Helber U
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Adult ,Male ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Kallikrein-Kinin System ,Administration, Oral ,Bradykinin ,Angiotensin-Converting Enzyme Inhibitors ,Coronary Disease ,Myocardial Reperfusion Injury ,Pharmacology ,law.invention ,chemistry.chemical_compound ,Double-Blind Method ,Enalapril ,law ,Internal medicine ,medicine ,Cardiopulmonary bypass ,Humans ,Aprotinin ,Coronary Artery Bypass ,Intraoperative Complications ,Aged ,Aged, 80 and over ,Hemostasis ,biology ,Troponin T ,business.industry ,Fibrinogen ,Heart ,Kallikrein ,Middle Aged ,chemistry ,biology.protein ,Cardiology ,Female ,Surgery ,Creatine kinase ,Cardiology and Cardiovascular Medicine ,business ,circulatory and respiratory physiology ,medicine.drug - Abstract
BACKGROUND ACE inhibitors may have a cardioprotective effect by enhancing bradykinin levels during cardiopulmonary bypass (CPB). However, ACE inhibition could lead to unwelcome effects on the kallikrein contact phase during CPB (since reduction of kallikrein activity by aprotinin has been shown to be beneficial) and may alter the hemostasis. We examined the effects of ACE inhibitors on intraoperative myocardial damage, kallikrein contact phase and hemostasis in patients undergoing CPB. METHODS 47 patients randomly received either 20 mg/d enalapril or placebo. Creatine kinase (CK and CK-MB), lactate dehydrogenase (LDH), troponin T (TnT), thrombin-antithrombin III complex (TAT), fibrinogen and kallikrein-like activity were measured before surgery, during and immediately after CPB, at the end of surgery and 1, 3 and 5 days after surgery. RESULTS No significant differences between enalapril- and placebo- treated patients concerning CK (318 +/- 38.6 U/l vs. 316 +/- 16.8 U/l), CK-MB, LDH, TnT (1.81 +/- 0.45 ng/ml vs. 1.52 +/- 0.34 ng/ml), TAT, fibrinogen and kallikrein-like-activity could be found during study period. CONCLUSIONS Reduction of ischemic injury during CPB is not achieved with ACE inhibitors. However, treatment of patients with ACE inhibitors before and during CPB is fully feasible without side effects affecting the kallikrein contact phase or significant influence on hemostasis.
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- 2002
5. Kardio-MR zur Bestimmung links-ventrikulärer Funktionsparameter
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Miller, S., primary, Hahn, U., additional, Bail, D., additional, Helber, U., additional, Nägele, T., additional, Scheule, A., additional, Schick, F., additional, Duda, S., additional, and Claussen, C., additional
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- 2008
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6. 1 M Gd-chelate (gadobutrol) for multislice first-pass magnetic resonance myocardial perfusion imaging
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Fenchel, M, primary, Franow, A, additional, Martirosian, P, additional, Engels, M, additional, Kramer, U, additional, Stauder, N I, additional, Helber, U, additional, Vogler, H, additional, Claussen, C D, additional, and Miller, S, additional
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- 2007
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7. Myocardial Perfusion MR-Imaging at 3 Tesla
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Klumpp, B, primary, Helber, U, additional, Fenchel, M, additional, Kramer, U, additional, Hövelborn, T, additional, May, A, additional, Stauder, NI, additional, Claussen, CD, additional, and Miller, S, additional
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- 2006
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8. Beurteilung der kardialen Beteiligung bei systemischer Amyloidose mit MR-Bildgebung
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Klumpp, B, primary, Fenchel, M, additional, Franow, A, additional, Helber, U, additional, Stauder, NI, additional, Kramer, U, additional, Claussen, CD, additional, and Miller, S, additional
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- 2005
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9. Beurteilung der Myokardperfusion mit Magnetresonanztomographie bei 3.0T
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Klumpp, B, primary, Fenchel, M, additional, Franow, A, additional, Helber, U, additional, Kramer, U, additional, Stauder, NI, additional, Claussen, CD, additional, and Miller, S, additional
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- 2005
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10. Myokardiale Vitalitätsdiagnostik mit Late Enhancement MR-Bildgebung bei 3.0T im Vergleich zu 1.5T
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Klumpp, B, primary, Fenchel, M, additional, Kramer, U, additional, Stauder, NI, additional, Franow, A, additional, Helber, U, additional, Claussen, CD, additional, and Miller, S, additional
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- 2005
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11. Entwicklung einer Matlab-basierten Software zur semiquantitativen Analyse der MR First-pass Myokardperfusion
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Fenchel, M, primary, Kramer, U, additional, Stauder, N, additional, Helber, U, additional, Claussen, CD, additional, and Miller, S, additional
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- 2003
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12. Single-breath-hold MR-Bildgebung zur Detektion linksventrikulärer Funktionsstörungen unter Dipyridamol-Stress bei KHK
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Kramer, U, primary, Fenchel, M, additional, Helber, U, additional, Stauder, N, additional, Claussen, C, additional, and Miller, S, additional
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- 2003
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13. Influence of ACE Inhibition on Myocardial Damage, the Kallikrein-Kinin System and Hemostasis during Cardiopulmonary Bypass Surgery
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Walter, T., primary, Helber, U., additional, Bail, D., additional, Heller, W., additional, and Hoffmeister, H. M., additional
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- 2002
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14. Variabilität MR-tomographisch bestimmbarer myokardialer Funktions- und Perfusionsparameter bei gesunden Probanden
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Kramer, U., primary, Miller, S., additional, Helber, U., additional, Schick, F., additional, Nägele, T., additional, Brechtel, K., additional, Huppert, P., additional, and Claussen, C. D., additional
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- 2000
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15. MR angiography and flow quantification of the internal mammary artery graft after minimally invasive direct coronary artery bypass.
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Miller, S, primary, Scheule, A M, additional, Hahn, U, additional, Jurmann, M, additional, Helber, U, additional, Duda, S H, additional, Stauder, N I, additional, and Claussen, C D, additional
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- 1999
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16. MR-tomographische Untersuchung myokardialer Funktion und Perfusion nach Myokardinfarkt
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Miller, S., primary, Huppert, P., additional, Naegele, T., additional, Helber, U., additional, Brechtel, K., additional, Hoffmeister, H., additional, and (Haussen, C., additional
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- 1997
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17. Activation of the contact phase of the coagulation, of the kinin system and of the complement cascade by streptokinase in acute myocardial infarction
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Hoffmeister, H.M., primary, Ruf, M., additional, Wendel, H.P., additional, Helber, U., additional, Kazmaier, S., additional, Heller, W., additional, and Seipel, L., additional
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- 1997
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18. 75. Transient reduction in endothelial tPA-release in unstable angina pectoris
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Helber, U., primary, Beyer, M.E., additional, Jur, M., additional, Heller, W., additional, and Hoffmeister, H.M., additional
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- 1996
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19. 103. Coagulation and fibrinolysis in patients with acute coronary syndromes in the follow up
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Helber, U., primary, Jur, M., additional, Waldenmaier, S., additional, Heller, W., additional, and Hoffmeister, H.M., additional
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- 1996
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20. 76. Effect of cholesterol on fibrinolysis and atherosclerosis in ovariectomized rabbits
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Hoffmeister, A., primary, Hanke, H., additional, Helber, U., additional, Beyer, M., additional, Jur, M., additional, Hanke, S., additional, Koenig, W., additional, and Hoffmeister, H.M., additional
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- 1996
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21. 70. Correlation between the extent of morphological changes and alterations of the fibrinolysis and the coagulation in an experimental atherosclerosis model
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Beyer, M.E., primary, Hanke, H., additional, Helber, U., additional, Hoffmeister, A., additional, Bruck, B., additional, Kazmaier, S., additional, and Hoffmeister, H.M., additional
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- 1996
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22. Comparison of pulsed laser-assisted angioplasty and balloon angioplasty in femoropopliteal artery occlusions.
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Huppert, P E, primary, Duda, S H, additional, Helber, U, additional, Karsch, K R, additional, and Claussen, C D, additional
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- 1992
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23. Influence of ACE Inhibition on Myocardial Damage, [nl]the Kallikrein-Kinin System and Hemostasis [nl]during Cardiopulmonary Bypass Surgery.
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Walter, T., Helber, U., Bail, D., Heller, W., and Hoffmeister, H. M.
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- 2002
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24. The Thrombolytic Paradox
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Hoffmeister, H. M., Szabo, S., Helber, U., and Seipel, L.
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- 2001
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25. Correlation between coronary morphology and molecular markers of fibrinolysis in unstable angina pectoris
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Hoffmeister, H.M., Jur, M., Helber, U., Fischer, M., Heller, W., and Seipel, L.
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- 1999
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26. The challenge to detect heart transplant rejection and transplant vasculopathy non-invasively a pilot study
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Helber Uwe, Schroeder Stephen, Aebert Hermann, Burgstahler Christof, Usta Engin, Kopp Andreas F, and Ziemer Gerhard
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Surgery ,RD1-811 ,Anesthesiology ,RD78.3-87.3 - Abstract
Abstract Background Cardiac allograft rejection and vasculopathy are the main factors limiting long-term survival after heart transplantation. In this pilot study we investigated whether non-invasive methods are beneficial to detect cardiac allograft rejection (Grade 03 R) and cardiac allograft vasculopathy. Thus we compared multi-slice computed tomography and magnetic resonance imaging with invasive methods like coronary angiography and left endomyocardial biopsy. Methods 10 asymptomatic long-term survivors after heart transplantation (8 male, 2 female, mean age 52.1 ± 12 years, 73 ± 11 months after transplantation) were included. In a blinded fashion, coronary angiography and multi-slice computed tomography and ventricular endomyocardial biopsy and magnetic resonance imaging were compared against each other. Results Cardiac allograft vasculopathy and atherosclerosis were correctly detected by multi-slice computed tomography and coronary angiography with positive correlation (r = 1). Late contrast enchancement found by magnetic resonance imaging correlated positively (r = 0.92, r2 = 0.85, p < 0.05) with the histological diagnosis of transplant rejection revealed by myocardial biopsy. None of the examined endomyocardial specimen revealed cardiac allograft rejection greater than Grade 1 R. Conclusion A combined non-invasive approach using multi-slice computed tomography and magnetic resonance imaging may help to assess cardiac allograft vasculopathy and cardiac allograft rejection after heart transplantation before applying more invasive methods.
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- 2009
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27. The challenge to detect heart transplant rejection and transplant vasculopathy non-invasively - a pilot study.
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Usta E, Burgstahler C, Aebert H, Schroeder S, Helber U, Kopp AF, Ziemer G, Usta, Engin, Burgstahler, Christof, Aebert, Hermann, Schroeder, Stephen, Helber, Uwe, Kopp, Andreas F, and Ziemer, Gerhard
- Abstract
Background: Cardiac allograft rejection and vasculopathy are the main factors limiting long-term survival after heart transplantation.In this pilot study we investigated whether non-invasive methods are beneficial to detect cardiac allograft rejection (Grade 03 R) and cardiac allograft vasculopathy. Thus we compared multi-slice computed tomography and magnetic resonance imaging with invasive methods like coronary angiography and left endomyocardial biopsy.Methods: 10 asymptomatic long-term survivors after heart transplantation (8 male, 2 female, mean age 52.1 +/- 12 years, 73 +/- 11 months after transplantation) were included. In a blinded fashion, coronary angiography and multi-slice computed tomography and ventricular endomyocardial biopsy and magnetic resonance imaging were compared against each other.Results: Cardiac allograft vasculopathy and atherosclerosis were correctly detected by multi-slice computed tomography and coronary angiography with positive correlation (r = 1). Late contrast enchancement found by magnetic resonance imaging correlated positively (r = 0.92, r2 = 0.85, p < 0.05) with the histological diagnosis of transplant rejection revealed by myocardial biopsy. None of the examined endomyocardial specimen revealed cardiac allograft rejection greater than Grade 1 R.Conclusion: A combined non-invasive approach using multi-slice computed tomography and magnetic resonance imaging may help to assess cardiac allograft vasculopathy and cardiac allograft rejection after heart transplantation before applying more invasive methods. [ABSTRACT FROM AUTHOR]- Published
- 2009
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28. Fibrin specificity and procoagulant effect related to the kallikrein-contact phase system and to plasmin generation with double-bolus reteplase and front-loaded alteplase thrombolysis in acute myocardial infarction.
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Hoffmeister, Hans Martin, Kastner, Christof, Hoffmeister, H M, Kastner, C, Szabo, S, Beyer, M E, Helber, U, Kazmaier, S, Baumbach, A, Wendel, H P, and Heller, W
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MYOCARDIAL infarction treatment , *HEMOSTASIS , *FIBRINOLYSIS , *FIBRINOLYTIC agents , *ANTICOAGULANTS , *BLOOD coagulation factors , *COMBINATION drug therapy , *CLINICAL trials , *COMPARATIVE studies , *DRUG administration , *DOSE-effect relationship in pharmacology , *FIBRIN , *LONGITUDINAL method , *RESEARCH methodology , *MEDICAL cooperation , *MYOCARDIAL infarction , *PROTEOLYTIC enzymes , *RECOMBINANT proteins , *RESEARCH , *THROMBIN , *THROMBOLYTIC therapy , *TISSUE plasminogen activator , *DISEASE relapse , *EVALUATION research , *RANDOMIZED controlled trials , *PHARMACODYNAMICS - Abstract
This study was undertaken to compare the effects of reteplase and alteplase regimens on hemostasis and fibrinolysis in acute myocardial infarction (AMI). Thrombolytic treatment in patients with AMI is hampered by paradoxical procoagulant effects that favor early reocclusion. In vivo data comparing this effect and the fibrin specificity of double-bolus reteplase and front-loaded alteplase regimens are not available. In a prospective, randomized study, 50 patients with AMI were either treated with double bolus (10 + 10 U) reteplase or with front-loaded alteplase (up to 100 mg) within 6 hours of symptom onset. Thirty apparently healthy persons served as controls. Molecular markers of coagulation and fibrinolysis were serially examined for up to 5 days. Paradoxical thrombin activation at 3 hours after initiation of therapy was comparable between reteplase and alteplase. Reteplase (65 +/- 5 U/L) and alteplase (72 +/- 8 U/L) caused significantly elevated kallikrein activity at 3 hours after adminstration (p <0.01 vs controls 30 +/- 1 U/L). Fibrin specificity was less for reteplase (p <0.05) with a decrease in fibrinogen at 3 hours to 122 +/- 27 mg/dl versus 224 +/- 28 mg/dl for alteplase (p <0.01 and p <0.05 vs controls). D-Dimer levels at 3 hours were higher (p <0.05) after reteplase (5,459 +/- 611 ng/ml) versus alteplase (3,445 +/- 679 ng/ml) (both p <0.01 vs controls 243 +/- 17 ng/ml). Plasmin generation (plasmin-antiplasmin complexes) was significantly (p <0.01) increased at 3 hours with both regimens to 27,079 +/- 3,964 microg/L (reteplase) and 19,522 +/- 2,381 microg/L (alteplase). The data from 3 hours after start of thrombolytic therapy proved less marked fibrin specificity of the reteplase regimen (in vivo) compared with front-loaded alteplase. Both regimens have a moderate procoagulant effect without differences in activation of the kallikrein system. [ABSTRACT FROM AUTHOR]
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- 2000
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29. Successful local antiproliferative paclitaxel delivery in a repeatedly restenosed lesion of the right coronary artery after drug eluting-stent implantation.
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Herdeg C, Göhring-Frischholz K, Helber U, Geisler T, May A, Haase KK, and Gawaz M
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- Angina Pectoris therapy, Catheterization methods, Coronary Artery Disease therapy, Humans, Male, Middle Aged, Angioplasty, Balloon, Coronary, Coronary Restenosis therapy, Drug-Eluting Stents, Paclitaxel administration & dosage
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- 2008
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30. Inappropriate implantable cardioverter-defibrillator shock induced by electromagnetic interference while taking a shower.
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Fernengel A, Schwer C, Helber U, and Dörnberger V
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- Adult, Cardiomyopathy, Hypertrophic diagnosis, Cardiomyopathy, Hypertrophic genetics, Electrocardiography, Female, Humans, Prosthesis Design, Ventricular Fibrillation diagnosis, Baths, Cardiomyopathy, Hypertrophic therapy, Defibrillators, Implantable adverse effects, Electromagnetic Fields adverse effects, Electroshock adverse effects, Prosthesis Failure, Ventricular Fibrillation etiology
- Published
- 2007
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31. Assessment of myocardial viability using delayed enhancement magnetic resonance imaging at 3.0 Tesla.
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Klumpp B, Fenchel M, Hoevelborn T, Helber U, Scheule A, Claussen C, and Miller S
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- Adult, Aged, Aged, 80 and over, Female, Humans, Magnetic Resonance Imaging instrumentation, Magnetics, Male, Middle Aged, Myocardial Infarction pathology, Reference Values, Sensitivity and Specificity, Ventricular Dysfunction, Left pathology, Contrast Media, Image Enhancement, Magnetic Resonance Imaging methods, Myocardial Infarction diagnosis, Ventricular Dysfunction, Left diagnosis
- Abstract
Objective: Cardiac magnetic resonance imaging (MRI) at 3.0 T has recently become available and potentially provides a significant improvement of tissue contrast in T1-weighted imaging techniques relying on Gd-based contrast enhancement. Imaging at high-field strength may be especially advantageous for methods relying on strong T1-weighting and imaging after contrast material administration. The aim of this study was to compare cardiac delayed enhancement (DE) MRI at 3.0 T and 1.5 T with respect to image quality, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) between infarcted and normal myocardium., Materials and Methods: Forty consecutive patients with history of myocardial infarction were examined at 3.0 T (n = 20) or at 1.5 T (n = 20). Myocardial function was assessed using cine steady-state-free-precession (SSFP) sequences (TR 3.1 milliseconds, TE 1.6 milliseconds, flip angle 70 degrees , and a matrix of 168 x 256 at 1.5 T and TR 3.4 milliseconds, TE 1.7 milliseconds, flip angle 50 degrees and a matrix of 168 x 256 at 3.0 T), acquired in long- and short-axes views. DE images were obtained 15 minutes after the administration of 0.15 mmol of Gd-DTPA/kg body weight using a segmented inversion recovery prepared gradient echo sequence at 1.5 T (TR 9.6 milliseconds, TE 4.4 milliseconds, flip angle 25 degrees , matrix 160 x 256, bandwidth 140 Hertz/pixel) and at 3.0 T (TR 9.8 milliseconds, TE 4.3 milliseconds, flip angle 30 degrees , matrix 150 x 256, bandwidth 140 Hertz/pixel). For image analysis, standardized SNR and CNR measurements were performed in infarcted and remote myocardial regions. Two independent observers rated image quality on a 4-point scale (0 = poor image quality, 1 = sufficient image quality, 2 = good image quality, 3 = excellent image quality)., Results: High diagnostic image quality was obtained in all patients. Rating of mean image quality was 2.2 +/- 0.8 at 1.5 T and 2.5 +/- 0.6 at 3.0 T (P = 0.012) for observer 1 and 2.2 +/- 0.7 at 1.5 T and 2.6 +/- 0.6 at 3.0 T (P = 0.003) for observer 2, respectively. Interobserver agreement was good (kappa = 0.68 at 1.5 T and 0.78 at 3.0 T). SNR measurements yielded a mean SNR of 37.8 +/- 13.9/22.9 +/- 6.0 in infarcted myocardium (P < 0.001) and 5.6 +/- 2.2/5.9 +/- 2.4 in normal myocardium (P = 0.45) at 3.0 T/1.5 T, respectively. CNR measurements revealed mean values of 32.4 +/- 13.0/16.7 +/- 5.4 (P< 0.001) at 3.0 T/1.5 T, respectively., Conclusions: Delayed enhancement MRI at 3.0 T is feasible and provides superior image quality compared with 1.5 T. Furthermore, using identical contrast doses, increased SNR and CNR values were recorded at 3.0 T.
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- 2006
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32. Combined thrombolysis with abciximab favourably influences platelet-leukocyte interactions and platelet activation in acute myocardial infarction.
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Szabo S, Etzel D, Ehlers R, Walter T, Kazmaier S, Helber U, and Hoffmeister HM
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- Abciximab, Aged, Blood Platelets metabolism, Blood Platelets pathology, Cell Adhesion Molecules biosynthesis, Female, Humans, Male, Middle Aged, Monocytes metabolism, Monocytes pathology, Myocardial Infarction blood, Neutrophils metabolism, Neutrophils pathology, Platelet Aggregation, Platelet Glycoprotein GPIIb-IIIa Complex antagonists & inhibitors, Antibodies, Monoclonal therapeutic use, Immunoglobulin Fab Fragments therapeutic use, Myocardial Infarction drug therapy, Platelet Aggregation Inhibitors therapeutic use, Thrombolytic Therapy
- Abstract
Background: In patients with acute myocardial infarction (AMI), activated platelets and altered haemostatic/fibrinolytic systems with and without thrombolytic therapy are known. Platelets thereby interact with neutrophils, stimulated endothelial cells and with monocytes leading to adverse effects on further myocardial damage. Thrombolysis in these patients is still hampered by procoagulant effects favoring early reocclusion. The additional treatment with a GPIIb/IIIa antagonist aimed to minimize early reocclusion thus improving the present therapeutic regimen., Methods: In 38 patients with AMI, we investigated the effects of a thrombolytic regimen with half reteplase (r-PA) dose plus abciximab vs. full dose r-PA on membrane-bound adhesion molecules (CD41, CD42b, CD40, CD40L) expressed on platelets, neutrophils and monocytes as well as on soluble platelet-selectin as interaction and activation markers of these cells., Results: The combination group had significantly (p < 0.05) lower sP-selectin levels over 48 h vs. the group treated with full dose r-PA. After 3 h, the percentage of CD41 and CD42b positive monocytes and granulocytes as well as the percentage of CD40 positive granulocytes and the percentage of CD40L positive monocytes markedly (p < 0.01, p < 0.05) decreased in the combination group vs. data at admission compared with the r-PA group indicating less leukocyte-patelet adhesion., Conclusions: The thrombolytic regimen with half dose r-PA and abciximab had a benefical influence on platelet activation and induced a more marked decrease of platelet-monocyte, and in part, platelet-granulocyte aggregates compared with the r-PA regimen. This could contribute to a probably lesser monocyte activation state with favourable effects on monocyte-endothelial adhesion and a consecutively possible influence of myocardial damage, a reduction of the additionally acute local inflammatory processes and a reduction of adherence of platelet-granulocyte aggregates to subendothelium.
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- 2005
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33. Myocardial perfusion after angioplasty in patients suspected of having single-vessel coronary artery disease: improvement detected at rest-stress first-pass perfusion MR imaging--initial experience.
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Fenchel M, Franow A, Stauder NI, Kramer U, Helber U, Claussen CD, and Miller S
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- Adult, Aged, Coronary Angiography, Coronary Disease diagnostic imaging, Female, Follow-Up Studies, Humans, Male, Middle Aged, Prospective Studies, Stents, Tomography, Emission-Computed, Single-Photon, Angioplasty, Balloon, Coronary, Coronary Circulation physiology, Coronary Disease physiopathology, Coronary Disease therapy, Magnetic Resonance Imaging methods
- Abstract
Purpose: To prospectively assess myocardial perfusion before and after successful intervention in patients suspected of having single-vessel coronary artery disease by using a steady-state free precession (SSFP) perfusion magnetic resonance (MR) imaging sequence., Materials and Methods: Local ethics committee approval and informed consent were obtained. Rest-stress perfusion MR imaging studies were performed in 18 patients with coronary artery disease (12 men, six women; mean age, 58.6 years +/- 13.6 [standard deviation]; range, 30-79 years) at 1.5 T with a multisection saturation-recovery SSFP sequence and 0.025 mmol gadopentetate dimeglumine per kilogram of body weight. MR studies were performed before (n = 18), several days after (n = 18), and 8 months after (n = 10) coronary intervention. Nine patients underwent percutaneous transluminal coronary angioplasty (PTCA) alone, and nine patients underwent PTCA with stent placement. Myocardial perfusion reserve index (MPRI) was calculated by dividing results of myocardial perfusion at maximal vasodilation by results at rest. The standard for myocardial perfusion was technetium 99m tetrofosmin single photon emission computed tomography. Statistical significance was tested with univariate variance analysis and Student t tests., Results: In the area of the stenosed vessel, MPRI was 1.04 +/- 0.24 before treatment and 2.18 +/- 0.57 several days afterward (P < .001). In remote areas, MPRI was 2.42 +/- 0.44. In the stent group, MPRI increased by 156%, from 0.99 +/- 0.20 before stent placement to 2.53 +/- 0.53 after (P < .001). Similarly, in the PTCA only group, MPRI increased by 72%, from 1.08 +/- 0.27 before PTCA to 1.87 +/- 0.39 after (P < .001). At follow-up in patients without recurring chest pain, MPRI was 2.14 +/- 0.37 in the area of the treated artery and 2.29 +/- 0.47 in remote areas (P = .06)., Conclusion: The MPRI, derived from rest-stress examinations, can provide information on success of interventional procedures in stenosed coronary arteries., (RSNA, 2005)
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- 2005
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34. Detection of regional myocardial perfusion deficit using rest and stress perfusion MRI: a feasibility study.
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Fenchel M, Helber U, Kramer U, Stauder NI, Franow A, Claussen CD, and Miller S
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- Adult, Aged, Contrast Media, Coronary Artery Disease diagnostic imaging, Feasibility Studies, Female, Gadolinium DTPA, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Radionuclide Imaging, Sensitivity and Specificity, Coronary Artery Disease pathology, Coronary Circulation, Magnetic Resonance Imaging methods
- Abstract
Objective: Providing high temporal and spatial resolution, perfusion MRI is an attractive alternative to traditional radionuclide methods like SPECT and PET. Although first-pass perfusion MRI examinations have gained increasing attention during the past years, this technique still exhibits relatively low signal-to-noise ratio and cardiac coverage. Previous studies have suggested that refocused gradient sequence technology (e.g., true fast imaging with steady-state precession [FISP]) should improve perfusion MRI examinations. The aim of this study was to assess myocardial perfusion deficits in patients with proven coronary artery disease using a saturation recovery true FISP perfusion sequence., Subjects and Methods: Rest and stress perfusion MRI studies were performed in 22 patients with coronary artery disease at 1.5 T using a multislice saturation recovery true FISP sequence after the bolus injection of 0.025 mmol/kg of body weight of gadopentetate dimeglumine. The myocardium of each slice was divided into 12 radial segments with subdivision into subendocardial and subepicardial subregions. Myocardial perfusion was assessed semiquantitatively and independently for each subregion. The standard of reference for myocardial perfusion was SPECT. Delayed enhancement images were acquired after the injection of 0.15 mmol/kg of body weight of gadopentetate dimeglumine., Results: Sensitivity and specificity of perfusion MRI examinations for the detection of perfusion deficits were 81% and 89%, respectively, for the semiquantitative perfusion parameter upslope and 78% and 86% for the parameter peak signal intensity. More specifically, rest perfusion examinations were able to detect areas of infarction, whereas stress examinations increased the perfusion differences between normal and ischemic myocardial areas. Excellent correlation was observed between rest perfusion and late enhancement findings (r = 0.90)., Conclusion: In patients with single-vessel coronary artery disease, perfusion deficits can reliably be detected using a saturation recovery true FISP sequence. Semiquantitative perfusion parameters upslope and peak signal intensity yielded similar results.
- Published
- 2005
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35. Semiquantitative assessment of myocardial perfusion using magnetic resonance imaging: evaluation of appropriate thresholds and segmentation models.
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Fenchel M, Kramer U, Helber U, Stauder NI, Franow A, Claussen CD, and Miller S
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- Adult, Aged, Contrast Media, Coronary Disease diagnostic imaging, Coronary Disease physiopathology, Female, Gadolinium DTPA, Humans, Male, Middle Aged, Organophosphorus Compounds, Organotechnetium Compounds, Radiopharmaceuticals, Sensitivity and Specificity, Tomography, Emission-Computed, Single-Photon, Coronary Circulation, Coronary Disease diagnosis, Magnetic Resonance Imaging methods
- Abstract
Rationale and Objectives: The aim of the study was to determine optimal thresholds for semiquantitative perfusion parameters and to evaluate the influence of different segmentation models in detecting malperfused regions., Material and Methods: In 6 healthy subjects and 13 patients with coronary artery disease, contrast-enhanced first-pass perfusion imaging was performed using a SR-TrueFISP-sequence. Thresholds for semiquantitative parameters were established, and different segmentation models of the left ventricular myocardium were tested. The standard of reference for patient studies was single photon emission computed tomography., Results: Optimal thresholds were determined in healthy subjects for the perfusion parameters upslope, AUC, and peak SI of mv-0.5*std, mv-1.5*std, and mv-1.0*std, respectively. Using the optimal threshold for each parameter/segmentation combination sensitivities and specificities of stress studies were between 66% and 93% and 77% and 92%, respectively. Subdivision of radial segments into subendo/subepicardial segments increased sensitivities for perfusion deficits., Conclusions: Subdivision of radial myocardial segments is essential in analysis of magnetic resonance first-pass perfusion series. Semiquantitative perfusion parameters possess different sensitivities for the detection of perfusion deficits.
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- 2004
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36. Multislice first-pass myocardial perfusion imaging: Comparison of saturation recovery (SR)-TrueFISP-two-dimensional (2D) and SR-TurboFLASH-2D pulse sequences.
- Author
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Fenchel M, Helber U, Simonetti OP, Stauder NI, Kramer U, Nguyen CN, Finn JP, Claussen CD, and Miller S
- Subjects
- Adult, Aged, Coronary Circulation, Humans, Male, Middle Aged, Phantoms, Imaging, Reference Values, Sensitivity and Specificity, Coronary Artery Disease physiopathology, Heart physiopathology, Magnetic Resonance Imaging methods
- Abstract
Purpose: To compare signal-to-noise ratio (SNR), contrast-to-noise (CNR) ratio, and diagnostic accuracy of a newly developed saturation recovery (SR)-TrueFISP-two-dimensional (2D) sequence with an SR-TurboFLASH-2D sequence., Materials and Methods: In seven healthy subjects and nine patients with coronary artery disease (CAD), contrast-enhanced perfusion imaging (with Gd-DTPA) was performed with SR-TrueFISP and SR-TurboFLASH sequences. Hypoperfused areas were assessed qualitatively (scale = 0-4). Furthermore, SNR and CNR were calculated and semiquantitative perfusion parameters were determined from signal intensity (SI) time curves. Standard of reference for patient studies was single-photon emission computer tomography (SPECT) and angiography., Results: The perception of perfusion deficits was superior in TrueFISP images (2.6 +/- 1.0) than in TurboFLASH (1.4 +/- 0.6) (P < 0.001). Phantom measurements yielded increased SNR (143 +/- 34%) and CNR (158 +/- 64%) values for TrueFISP. In patient/volunteer studies SNR was 61% to 100% higher and signal enhancement was 110% to 115% higher with TrueFISP than with TurboFLASH. Qualitative and semiquantitative assessment of perfusion defects yielded higher sensitivities for detection of perfusion defects with TrueFISP (68% to 78%) than with TurboFLASH (44% to 59%)., Conclusion: SR-TrueFISP-2D perfusion imaging provides superior SNR and CNR than TurboFLASH imaging. Moreover, the dynamic range of SIs was found to be higher with TrueFISP, resulting in an increased sensitivity for detection of perfusion defects., (Copyright 2004 Wiley-Liss, Inc.)
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- 2004
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37. Increased fibrin specificity and reduced paradoxical thrombin activation of the combined thrombolytic regimen with reteplase and abciximab versus standard reteplase thrombolysis.
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Szabo S, Etzel D, Ehlers R, Walter T, Kazmaier S, Helber U, Beyer ME, and Hoffmeister HM
- Subjects
- Abciximab, Aged, Dose-Response Relationship, Drug, Drug Therapy, Combination, Female, Fibrinolytic Agents administration & dosage, Humans, Male, Middle Aged, Platelet Aggregation drug effects, Recombinant Proteins administration & dosage, Tissue Plasminogen Activator administration & dosage, Antibodies, Monoclonal therapeutic use, Anticoagulants therapeutic use, Fibrinolytic Agents therapeutic use, Immunoglobulin Fab Fragments therapeutic use, Myocardial Infarction drug therapy, Recombinant Proteins therapeutic use, Tissue Plasminogen Activator therapeutic use
- Abstract
In patients with acute myocardial infarction treated with thrombolytics, platelet activation as well as alterations of the hemostatic and fibrinolytic systems have been described favoring early infarct-related artery reocclusion. We investigated the effects of a newer thrombolytic regimen with half-dose double-bolus reteplase (2 x 5 IU, 20 patients) combined with abciximab versus full-dose reteplase (2 x 10 IU, 18 patients) on the fibrinolytic and the hemostatic system in patients with acute ST-segment elevation (in the electrocardiogram) myocardial infarction. The thrombolytic regimen with half-dose reteplase in combination with abciximab caused in vivo a lower systemic plasminemia and a lower paradoxical activation of the contact phase of the coagulation system (measured as activated factor XII); a lower paradoxical thrombin activation/generation; and a lesser extent of fibrinogen breakdown compared with the reteplase regimen. These results could be, at least in part, a possible explanation for the observed significantly lower rates of reinfarction until 7 days after enrollment and of recurrent ischemia in the combination group in the Global Use of Strategies to Open Occluded Coronary Arteries V (GUSTO V) trial.
- Published
- 2004
38. [Multislice TrueFISP-MR imaging for identifying stress-induced myocardial functional disturbances in coronary heart disease].
- Author
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Kramer U, Fenchel M, Helber U, Kraft A, Stauder NI, Franow A, Claussen CD, and Miller S
- Subjects
- Adult, Aged, Aged, 80 and over, Cardiac Volume physiology, Coronary Angiography, Coronary Disease physiopathology, Dipyridamole, Female, Heart Ventricles physiopathology, Humans, Male, Mathematical Computing, Middle Aged, Myocardial Contraction physiology, Prospective Studies, Reproducibility of Results, Stroke Volume physiology, Vasodilator Agents, Ventricular Dysfunction, Left physiopathology, Ventricular Function, Left physiology, Coronary Disease diagnosis, Exercise Test, Image Enhancement methods, Image Processing, Computer-Assisted methods, Magnetic Resonance Imaging, Cine methods, Ventricular Dysfunction, Left diagnosis
- Abstract
Purpose: This study assesses the left ventricular function using a new multislice cine sequence and determines the diagnostic accuracy of stress-induced wall motion abnormalities in patients with coronary artery disease (CAD)., Materials and Methods: 15 patients (mean age 57.7 years) with angiographically proven CAD were examined on a 1.5 T whole body system (Magnetom Sonata, Siemens, Erlangen) at rest and during dipyridamole-induced (0.56 mg/kg body weight) stress. Left ventricular function was determined using a multislice (steady-state) sequence (TR 2.3 ms, TE 1.15 ms, slice thickness 10 mm, temporal resolution 77 ms) as well as a standard single-slice true FISP 2D sequence (TR 3.2 ms, TE 1.6 ms, slice thickness 5 mm, temporal resolution 45 ms) as reference., Results: Both cine sequences provide high sensitivity and excellent correlation (r = 0.95) with angiographic findings for the detection of regional wall motion abnormalities. However, the measurement of functional parameters yielded significant differences. End-systolic left ventricular volumes (ESV) were systematically overestimated in the multislice images (mean 78 ml, + 5.8 %) compared with the reference single-slice images (mean 74 ml) (p < 0.05). This resulted in underestimation of the ejection fraction with multislice images (mean 40 %, - 11.3 %) compared with single-slice images (mean 46 %) (p < 0.05)., Conclusion: The multislice sequence results in a substantial reduction of imaging time and breath-hold periods necessary to cover the left ventricle for functional assessment. The multislice sequence yields adequate images, especially for qualitative determination of wall motion abnormalities. Due to the reduced spatial and temporal resolution of the multi-slice sequence, however, some uncertainty concerning the functional parameters has to be taken into account.
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- 2003
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39. MR imaging at rest early after myocardial infarction: detection of preserved function in regions with evidence for ischemic injury and non-transmural myocardial infarction.
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Miller S, Helber U, Brechtel K, Nägele T, Hahn U, Kramer U, Hoffmeister HM, and Claussen CD
- Subjects
- Aged, Angioplasty, Balloon, Coronary methods, Cohort Studies, Contrast Media, Female, Heart Function Tests, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Angiography methods, Male, Middle Aged, Myocardial Infarction therapy, Myocardial Reperfusion Injury diagnostic imaging, Myocardial Reperfusion Injury pathology, Observer Variation, Probability, Prognosis, Prospective Studies, Radiography, Sensitivity and Specificity, Severity of Illness Index, Stroke Volume, Time Factors, Ventricular Function, Left physiology, Gadolinium DTPA, Magnetic Resonance Imaging, Cine methods, Myocardial Infarction pathology
- Abstract
Patients with subacute myocardial infarction were studied to detect regions of ischemic injury but with preserved myocardial function combining different MRI techniques. On a 1.5-T imaging system 27 patients were examined 7-14 days after acute myocardial infarction. The imaging protocol included T2-weighted fast spin-echo imaging, a cine fast low-angle shot (FLASH) 2D technique to determine regional function at rest, and a first pass as well as late contrast enhancement perfusion study injecting 0.1 mmol/kg Gd-DTPA. Preserved function was compared with the transmural extent of first-pass perfusion phenomena, increased T2 signal intensity (SI), and late contrast enhancement. Semi-quantitative first-pass perfusion parameters were correlated with quantitative myocardial wall thickening (MWT) and degree of coronary artery stenosis. Indicating ischemic injury increased T2 SI and late enhancement was present in 29 and 26% of segments. Preserved function was found predominantly in segments with non-transmural late enhancement (112 of 338 segments with late enhancement) and transmural increase of T2 SI (129 of 386 segments with increased T2 SI). A high-grade perfusion deficit was detected in 4% of all segments and regularly associated with markedly decreased systolic function. Correlation of first-pass perfusion parameters was observed with MWT (r=0.50-0.90, p<0.001) but not with the degree of coronary artery stenosis. Our data suggest that preserved function was detected in non-transmural myocardial infarction demonstrated by non-transmural late enhancement and increase of T2 SI.
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- 2003
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40. Relationship between minor myocardial damage and inflammatory acute-phase reaction in acute coronary syndromes.
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Hoffmeister HM, Ehlers R, Büttcher E, Steinmetz A, Kazmaier S, Helber U, Szabo S, Beyer ME, and Seipel L
- Subjects
- Acute Disease, Acute-Phase Proteins analysis, Acute-Phase Reaction diagnosis, Adult, Aged, Aged, 80 and over, Angina Pectoris pathology, Biomarkers blood, Blood Coagulation, Case-Control Studies, Coronary Disease pathology, Female, Hemostasis, Humans, Male, Middle Aged, Sensitivity and Specificity, Troponin T standards, Acute-Phase Reaction etiology, Myocardial Ischemia pathology, Troponin T blood
- Abstract
Background: In severe acute coronary syndromes (ACS) elevation of markers of inflammation and acute phase reaction (APR) like C-reactive protein (CRP) as well as a release of troponin have been reported. Using a high sensitivity troponin T (TnT) test we investigated whether an APR occurs in ACS only in the presence of ischemic myocardial damage., Methods: In 85 patients with ACS C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, thrombin antithrombin III complexes (TAT) and kallikrein were determined vs. high sensitive TnT (> or =0.02 ng/ml) initially and 2 d later vs. 45 patients with stable angina pectoris and 42 controls., Results: In stable angina pectoris, markers of inflammation and coagulation were slightly elevated (p < 0.05). Initially in ACS elevations of CRP to 1.2 +/- 0.3 mg/dl, SAA to 4.8 +/- 2.6 mg/dl and fibrinogen to 448 +/- 21 mg/dl (all p < 0.01 vs. controls) were found followed by a significant APR (p < 0.01). In the subgroup of TnT positive ACS patients, an APR with increased CRP (4.1 +/- 1.3 mg/dl), SAA (20.4 +/- 8.3 mg/dl), and fibrinogen (641 +/- 45 mg/dl) was detectable (all p < 0.05 vs. TnT negative patients). In contrast, patients without TnT release showed APR markers comparable to patients with stable angina pectoris., Conclusion: Our findings demonstrate an association between myocardial injury in ACS and acute phase reaction as evidenced by several molecular markers. A highly sensitive TnT-test identified myocardial injury in about all patients with APR while a standard TnT cut-off (0.1 ng/ml) missed 32% of these patients. Thus, the APR in patients with ACS is strongly associated with at least minor ischemic myocardial damage and prior findings of an APR independent from myocardial injury are probably based on less sensitive troponin tests.
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- 2003
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41. ECG-gated 18F-FDG positron emission tomography.
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Hoffmeister HM, Helber U, Franow A, Feine U, Bares R, Seipel L, and Müller-Schauenburg W
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- Adult, Aged, Dobutamine, Female, Gated Blood-Pool Imaging, Humans, Male, Middle Aged, Coronary Disease diagnostic imaging, Fluorodeoxyglucose F18, Radiopharmaceuticals, Tomography, Emission-Computed, Ventricular Function, Left physiology
- Abstract
Aim: 18F-fluorodeoxyglucose (18F-FDG)-positron emission tomography (PET) provides information about myocardial glucose metabolism to diagnose myocardial viability. Additional information about the functional status is necessary. Comparison of tomographic metabolic PET with data from other imaging techniques is always hampered by some transfer uncertainty and scatter. We wanted to evaluate a new Fourier-based ECG-gated PET technique using a high resolution scanner providing both metabolic and functional data with respect to feasibility in patients with diseased left ventricles., Methods: Forty-five patients with coronary artery disease and at least one left ventricular segment with severe hypokinesis or akinesis at biplane cineventriculography were included. A new Fourier-based ECG-gated metabolic 18F-FDG-PET was performed in these patients. Function at rest and 18F-FDG uptake were examined in the PET study using a 36-segment model., Results: Segmental comparison with ventriculography revealed a high reliability in identifying dysfunctional segments (> 96%). 18F-FDG uptake of normokinetic/hypokinetic/akinetic segments was 75.4 +/- 7.5, 65.3 +/- 10.5, and 35.9 +/- 15.2% (p < 0.001). In segments > or = 70% 18F-FDG uptake no akinesia was observed. No residual function was found below 40% 18F-FDG uptake. An additional dobutamine test was performed and revealed inotropic reserve (viability) in 42 akinetic segments and 45 hypokinetic segments., Conclusion: ECG-gated metabolic PET with pixel-based Fourier smoothing provides reliable data on regional function. Assessment of metabolism and function makes complete judgement of segmental status feasible within a single study without any transfer artefacts or test-to-test variability. The results indicate the presence of considerable amounts of viable myocardium in regions with an uptake of 40-50% 18F-FDG.
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- 2002
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42. Absence of paradoxical thrombin activation by fibrin-specific thrombolytics in acute myocardial infarction: comparison of single-bolus tenecteplase and front-loaded alteplase.
- Author
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Szabo S, Letsch R, Ehlers R, Walter T, Kazmaier S, Helber U, and Hoffmeister HM
- Subjects
- Aged, Anticoagulants administration & dosage, Anticoagulants therapeutic use, Antifibrinolytic Agents blood, Antithrombin III analysis, Aspirin administration & dosage, Aspirin therapeutic use, Biomarkers, Enzyme Activation drug effects, Factor XIIa analysis, Female, Fibrin Fibrinogen Degradation Products analysis, Fibrinolysin, Fibrinolysis drug effects, Hemostasis drug effects, Heparin administration & dosage, Heparin therapeutic use, Humans, Male, Middle Aged, Myocardial Infarction drug therapy, Peptide Fragments blood, Platelet Aggregation Inhibitors administration & dosage, Platelet Aggregation Inhibitors therapeutic use, Prothrombin, Recombinant Proteins administration & dosage, Recombinant Proteins pharmacology, Recombinant Proteins therapeutic use, Substrate Specificity, Tenecteplase, Tissue Plasminogen Activator administration & dosage, Tissue Plasminogen Activator blood, Tissue Plasminogen Activator therapeutic use, alpha-2-Antiplasmin, Fibrin drug effects, Fibrinolytic Agents pharmacology, Myocardial Infarction blood, Thrombin drug effects, Thrombolytic Therapy, Tissue Plasminogen Activator pharmacology
- Abstract
Objectives: Thrombolytic therapy in patients with acute myocardial infarction is hampered by bleeding complications and procoagulant effects favoring early reocclusion. TNK-tPA was shown in vitro to have considerable fibrin specificity. We investigated the effects of tenecteplase (TNK-tPA) and alteplase (rt-PA) on the haemostasis and fibrinolytic system., Methods and Results: We enrolled 30 patients with AMI into the study. Twenty patients received front-loaded rt-PA up to 100 mg; 10 patients were given TNK-tPA in a single bolus up to 50 mg. All patients received aspirin and intravenous heparin. During the first 2 days, the following parameters were repetitively determined: thrombin-antithrombin III complexes (TAT), antithrombin III (ATIII), prothrombin fragment F 1 + 2 (F 1 + 2), kallikrein-like activity (KK), activated factor XII (FXIIa), plasmin alpha 2-antiplasmin complexes (PAP), fibrinogen, D-dimers (DD), tissue-type plasminogen activator (t-PA). A total of 75 healthy persons served as control group. TAT increased significantly after rt-PA but not after TNK-tPA (3 h: 38.1 +/- 29.4 versus 10.5 +/- 4.2 microg/l; p < 0.01), indicating paradoxical thrombin activation. F 1 + 2 increased transiently after rt-PA but not after TNK-tPA. Fibrinogen was significantly lower after rt-PA versus TNK-tPA (3 h: 163 +/- 27 versus 380 +/- 54 mg/dl; p < 0.05). KK activities in the rt-PA group were significantly (p < 0.01) increased over 48 h versus TNK-tPA. PAP and D-dimers were lower over the time course of 48 h in the tenecteplase group versus rt-PA., Conclusions: This study indicates that tenecteplase has higher fibrin specificity not only in vitro but also in vivo versus alteplase. TNK-tPA consecutively has no paradoxical systemic procoagulant effect due to the lower extent of activation of the kallikrein-factor XII system than alteplase., (Copyright 2002 Elsevier Science Ltd.)
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- 2002
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43. Correlation between ST-T-segment changes with markers of hemostasis in patients with acute coronary syndromes.
- Author
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Ehlers R, Büttcher E, Eltzschig HK, Kazmaier S, Szabo S, Helber U, and Hoffmeister HM
- Subjects
- Acute Disease, Adult, Aged, Aged, 80 and over, Apolipoproteins blood, Biomarkers blood, C-Reactive Protein metabolism, Coronary Disease diagnosis, Coronary Disease epidemiology, Coronary Vessels pathology, Female, Fibrinogen metabolism, Follow-Up Studies, Germany epidemiology, Humans, Intercellular Adhesion Molecule-1 blood, Male, Middle Aged, Myocardial Infarction blood, Myocardial Infarction mortality, Patient Admission, Predictive Value of Tests, Risk Factors, Serum Amyloid A Protein, Statistics as Topic, Survival Analysis, Syndrome, Tissue Plasminogen Activator blood, Vascular Cell Adhesion Molecule-1 blood, Coronary Disease blood, Electrocardiography, Hemostasis physiology
- Abstract
Background: Disturbance of the hemostatic and the inflammatory system plays an important role in the pathophysiology of acute coronary syndromes (ACS). Their markers have been shown to predict further coronary events in patients with ACS. The prognostic value of the admission electrocardiogram (ECG), which is commonly used to evaluate ischemia, was studied previously. We investigated the correlation between serum markers of the hemostatic/inflammatory system and ECG changes in ACS., Methods: A standard 12-lead ECG was obtained from 85 patients with ACS on admission (0d). Markers of the hemostatic and inflammatory system were measured on admission and after 2 days (2d)., Results: Patients with ST-T-changes had higher fibrinogen and thrombin-antithrombin III complex (TAT) levels than patients without ECG alterations at both times (fibrinogen: 0d: 492 +/- 38 vs. 357 +/- 36 mg/dl, p < 0.01; 2d: 633 +/- 55 vs. 440 +/- 50 mg/dl, p < 0.02; TAT: 0d: 7.2 +/- 1.3 vs. 3.6 +/- 0.7 microg/l, p < 0.05; 2d: 5.3 +/- 0.9 vs. 3.2 +/- 0.5 microg/l, p < 0.05). Tissue-type plasminogen activator (TPA) was elevated in patients with ECG changes initially (10.1 +/- 0.6 vs. 7.2 +/- 0.7 ng/ml, p < 0.02). D-dimers, the acute-phase proteins C-reactive protein, serum amyloid A and the soluble adhesion molecules showed no significance., Conclusions: The data reveal a correlation between electrocardiographic changes and hemostasis in patients with ACS. The association of myocardial damage and a disturbed hemostatic system might stratify patients who are at high risk of suffering further coronary events., (Copyright 2002 S. Karger AG, Basel)
- Published
- 2002
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44. Myocardial troponin T release is associated with enhanced fibrinolysis in patients with acute coronary syndromes.
- Author
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Ehlers R, Büttcher E, Kazmaier S, Beyer ME, Helber U, Szabo S, Wendel HP, and Hoffmeister HM
- Subjects
- Acute Disease, Adult, Aged, Aged, 80 and over, Biomarkers blood, Case-Control Studies, Coronary Disease diagnosis, Female, Fibrin Fibrinogen Degradation Products metabolism, Fibrinolysin metabolism, Humans, Male, Middle Aged, Myocardium metabolism, Myocardium pathology, Plasminogen metabolism, Prognosis, Thrombophilia blood, Thrombophilia complications, Tissue Plasminogen Activator blood, Troponin T blood, Troponin T physiology, Coronary Disease blood, Fibrinolysis physiology, Troponin T metabolism
- Abstract
Patients with acute coronary syndromes (ACS) frequently present with signs of disturbed fibrinolysis. The present study investigates the correlation of alterations in the fibrinolytic system and the amount of myocardial damage characterized by troponin release. In 85 patients with ACS markers of plasmin activation, plasminogen activator system and troponin T (TnT) were measured initially and after 48 h. Patients with TnT release (> or = 0.01 microg/l) at admission had higher TPA levels than those without release (10.2+/-0.7 ng/ml vs. 7.6+/-0.5 ng/ml; p <0.01). Additionally, patients with positive TnT had higher D-dimer levels initially (457+/-39 ng/ml vs. 316+/-22 ng/ml; p <0.01) and 48 h later (451+/-42 ng/ml vs. 275+/-37 ng/ml; p <0.01). The association of myocardial damage with a prothrombotic state and an enhanced fibrinolysis may explain the high prognostic value of troponin measurements in respect to future coronary events.
- Published
- 2001
45. Subacute myocardial infarction: assessment by STIR T2-weighted MR imaging in comparison to regional function.
- Author
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Miller S, Helber U, Kramer U, Hahn U, Carr J, Stauder NI, Hoffmeister HM, and Claussen CD
- Subjects
- Aged, Computers, Female, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Time Factors, Magnetic Resonance Angiography methods, Magnetic Resonance Imaging methods, Myocardial Infarction diagnosis, Myocardium pathology
- Abstract
Purpose: Increased T2 signal intensity (SI) can be regularly observed in myocardial infarction. However, there are controversial reports about the relationship of elevated T2 SI to myocardial viability and some authors propose that high T2 SI serves as a sign of irreversible myocardial injury. This study investigates increased T2 SI compared to myocardial function in patients with reperfused subacute myocardial infarction. Preserved function was used as criterion for viability., Methods: Ten healthy volunteers and 17 patients with myocardial infarction and patent infarct related coronary artery were examined on a 1.5 T Magnetom Vision system (Siemens). For T2-weighted MR imaging a breath-hold STIR sequence with dark-blood preparation was used. Cine FLASH 2D imaging was applied to assess myocardial function. Signal-to-noise (S/N) in STIR T2 images was measured in normal and infarcted regions and subsequently identified by two independent observers. Based on a 20 segment model of the left ventricle findings were compared to regional myocardial function., Results: Elevated STIR T2 SI was found in all 17 patients and observed in 27% (204/754) of segments. S/N of normal myocardium was 5.1 +/- 0.7 in volunteers and 4.9 +/- 0.8 in patients (P = NS). Infarcted myocardium presented with significantly increased S/N 12.8 +/- 1.9 (P < 0.0001). Significant transmural elevation of T2 SI was noted in 32% of segments with preserved systolic function., Conclusion: Increased STIR T2 SI can be observed transmurally in post-ischemic myocardial regions with preserved function. It therefore cannot be used as an exclusive marker for the non-viable region.
- Published
- 2001
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46. [Variability in the MR tomographic determination of myocardial function and perfusion parameters in health subjects].
- Author
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Kramer U, Miller S, Helber U, Schick F, Nägele T, Brechtel K, Huppert P, and Claussen CD
- Subjects
- Adult, Contrast Media, Female, Heart Function Tests, Humans, Male, Perfusion, Reference Values, Heart anatomy & histology, Heart physiology, Magnetic Resonance Imaging methods
- Abstract
Purpose: The aim of the study was to evaluate myocardial function and perfusion patterns using magnetic resonance imaging in normal subjects., Materials and Methods: 22 healthy volunteers were examined. Cine-mode acquisitions along all three axes of the heart were generated and perfusion was measured on a mid-ventricular short-axis view. Myocardial wall thickening was scored and contrast enhancement during the first pass was analysed., Results: For myocardial wall thickening increasing values from base (24-86%) to apex (63-106%) were found. Contrast enhancement patterns showed regional variability. In addition marked individual differences were detectable., Conclusion: Perfusion patterns should be interpreted only in combination with functional parameters. Standard values for perfusion measurements cover very large range as a result of the high individual variability.
- Published
- 2000
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47. Fat- and water-selective MR cine imaging of the human heart: assessment of right ventricular dysplasia.
- Author
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Schick F, Miller S, Hahn U, Nägele T, Helber U, Stauder N, Brechtel K, and Claussen CD
- Subjects
- Adipose Tissue, Adult, Female, Humans, Male, Phantoms, Imaging, Water, Arrhythmogenic Right Ventricular Dysplasia diagnosis, Magnetic Resonance Imaging, Cine
- Abstract
Rationale and Objectives: The purpose of this study was to develop and implement MR sequences for chemical shift-selective breath-hold cine imaging of the heart. Fibroadipose conversion of myocardium in cases suspected of right ventricular dysplasia should be revealed in fat- and water-selective MR images of high quality., Methods: Frequency-selective saturation of one chemical shift component was applied in modified k-space-segmented, electrocardiography-gated sequences, allowing high-quality cine imaging of the human heart in a single breath-hold. Phantom studies and human examinations in eight normal subjects (aged 24-62 years) and in seven patients (aged 31-47 years) with suspected right ventricular dysplasia were performed. The patients showed suspicious findings, such as a dyskinetic and dilated right ventricle combined with ventricular arrhythmia, and underwent MR imaging after exclusion of other possible reasons (eg, coronary artery disease or pulmonary hypertension)., Results: High selectivity to the desired chemical shift component was confirmed by test measurements in a phantom containing water and lipids. In the human subjects, minor problems with magnetic field inhomogeneities appeared in the thoracic walls only. Four patients with suspected right ventricular dysplasia showed clearly abnormal signal behavior of the right myocardial wall in both fat- and water-selective cine images. Bright transmural structures were exhibited in fat-selective images, but the origin of the fat (epicardium or infiltrated myocardium) was often difficult to assess., Conclusions: Right ventricular areas with fibrosis and fatty degeneration often show normal signal intensity in standard T1-weighted images but can be differentiated from normal tissue by the new chemical shift-selective breath-hold cine techniques.
- Published
- 2000
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48. MR angiography and flow quantification of the internal mammary artery graft after minimally invasive direct coronary artery bypass.
- Author
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Miller S, Scheule AM, Hahn U, Jurmann M, Helber U, Duda SH, Stauder NI, and Claussen CD
- Subjects
- Contrast Media, Coronary Circulation, Gadolinium DTPA, Graft Occlusion, Vascular diagnosis, Humans, Male, Middle Aged, Minimally Invasive Surgical Procedures, Vascular Patency, Internal Mammary-Coronary Artery Anastomosis methods, Magnetic Resonance Angiography
- Abstract
Objective: Six patients who had undergone minimally invasive direct coronary artery bypass surgery were examined to evaluate an MR imaging protocol that provided information about cardiac function, bypass graft patency, and flow characteristics with a single examination., Conclusion: Preliminary results suggest that our imaging protocol allows accurate follow-up of patients after minimally invasive direct coronary artery bypass surgery. Bypass graft patency was correctly determined in all patients. In four patients, anastomoses were visualized by MR angiography, and flow measurements revealed a volume range of 28-84 ml/min (native and grafted internal mammary arteries) and a trend for the flow values of bypass grafts to be lower than those of native vessels. Interobserver reproducibility was good (r = .99; slope, .98).
- Published
- 1999
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49. Quantification of Viable Myocardium in Multivessel Coronary Disease: Effects of the Redistribution Time after Reinjection Of Thallium-201 and Comparison with Postrevascularization Defect Size.
- Author
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Helber U, Müller-Schauenburg W, and Hoffmeister HM
- Abstract
Reinjection of 201Tl is used for improved detection of viable myocardium. Prospectively the effect of the redistribution time after injection for the quantification of the definitive perfusion defect size in multivessel coronary heart disease and severely impaired left ventricular function was examined. Thirty patients were included preoperatively before CABG. The study was performed with 80-90 MBq 201Tl-Cl and reinjection (40-50 MBq). Imaging was performed after an exercise test and 3 hours afterwards. Thereafter, the reinjection dose was given and repeated studies were performed 10 minutes, 2 hours, and 20 hours later. Defect sizes were compared with the 3-hour rest-study without reinjection. Imaging studies were repeated postoperatively. The defect size was expressed as % of left ventricular total myocardium. Perfusion defect sizes were as follows: post-stress study (27%), 3 hour rest-study (17%), post-reinjection-10 min (12%), 2 hours (9%), and 20 hours (7%). Compared with the 3 hour rest-study, the perfusion defect was reduced only in 7/30 patients in the study immediately after reinjection. In the delayed studies, defect sizes were markedly smaller (p < 0.05) both in studies 2 hours and 20 hours after reinjection. In 15/30 patients there was a marked reduction of 50% of defect sizes in the study 2 hours post-reinjection vs the 3 hour rest-study. The residual defects at 2 hours after reinjection were identical to the postoperative defect sizes (10%). Further prolongation of the redistribution time to 20 horus caused an additional small reduction in defect size only in two patients compared with the 2-hour post-reinjection images (n.s.). Using a marker as 201Tl with redistribution characteristics, the redistribution time after reinjection is of utmost importance to correctly identify the definitive size of the perfusion defect vs viable myocardium in patients with multivessel disease. A delay of 2 hours for redistribution after the reinjection most correctly corresponds to the postop defect size; a longer redistribution time did not provide additional advantages.
- Published
- 1999
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50. [Cardiac MRI for determining functional left ventricular parameters].
- Author
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Miller S, Hahn U, Bail DM, Helber U, Nägele T, Scheule AM, Schick F, Duda SH, and Claussen CD
- Subjects
- Adult, Aortic Valve Insufficiency physiopathology, Aortic Valve Stenosis physiopathology, Cardiac Output physiology, Diastole physiology, Electrocardiography, Female, Humans, Male, Reference Values, Stroke Volume physiology, Ventricular Dysfunction, Left physiopathology, Ventricular Function, Left physiology, Aortic Valve Insufficiency diagnosis, Aortic Valve Stenosis diagnosis, Hemodynamics physiology, Magnetic Resonance Imaging, Cine, Ventricular Dysfunction, Left diagnosis
- Abstract
Purpose: To prove the accuracy of MR methods in the determination of left ventricular (LV) functional parameters and anatomy., Materials and Methods: At 1.5 T, 20 healthy volunteers and 22 patients with aortic valvular disease (stenosis n = 15, regurgitation n = 7) were examined. Functional parameters like cardiac output, ejection fraction, end-diastolic volume, aortic flow maximum, and time interval from the R-wave to maximum flow were obtained using a velocity encoding 2D FLASH sequence (TR 24 ms, TE 5 ms, venc 250 cm/sec) and segmented breath-hold cine FLASH 2D technique (TR 100 ms, TE 4.8 ms, flip angle 25 degrees, temporal resolution 50 ms). Invasive measurements (Fick principle) served as gold standard, intra- and interobserver variability were determined., Results: Differences of functional parameters between normal volunteers and patients were detectable at a high level of significance (p < 0.0001). For cardiac output a superior correlation with the gold standard was found using flow measurements (r = 0.66, p < 0.0007) compared to volumetric calculations from cine studies (r = 0.47, p < 0.02). Interobserver variability was 2.5 +/- 2.7%/4.5 +/- 6.9% (flow quantification/calculations from cine studies), intraobserver variability was 1.7 +/- 1.6%/3.3 +/- 2.2%., Conclusions: MRI is an appropriate tool for determining LV functional parameters and anatomy. Differences between normal volunteers and patients with aortic valvular disease can be detected reliably. Flow measurements turned out to be more accurate than calculations from cine images. Therefore, flow quantification techniques should be preferred for clinical use.
- Published
- 1999
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