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47 results on '"Baks, Timo"'

19. Different algorithms for quantitative analysis of myocardial infarction with DE MRI: comparison with autopsy specimen measurements

Author

Gruszcnska, KJ, Kirschbaum, Sharon, Baks, Timo, Moelker, Adriaan, Duncker, Dirk-jan, Rossi, Alexia, Baron, J, Feijter, Pim, Krestin, Gabriel, van Geuns, Robert Jan, Gruszczynska, K, Kirschbaum, S, Baks, T, Moelker, A, Duncker, Dj, Rossi, Alexia, Baron, J, de Feyter, Pj, Krestin, Gp, van Geuns, Rj, Radiology & Nuclear Medicine, and Cardiology

Subjects
quantitative analysis, Myocardial Infarction, cardiac magnetic resonance, quantitative analysi
Abstract

Rationale and Objectives: To compare two semiautomated methods for measurement of infarcted myocardium area on delayed contrast enhanced magnetic resonance imaging, with histopathology findings as standard of reference. Materials and Methods: Percentage area of myocardial infarction was measured in 10 Yorkshire landrace pigs manually and using two semiautomated methods. The first (standard deviation method) used two operator-selected regions of interest (ROIs) and nine different cutoff values (one to nine times the standard deviation of signal intensity in normal myocardium) to identify infarction. The second (threshold method) used threshold values based on percentages of maximum signal intensity to identify infarction. Results were compared with histopathology findings. Results: Difference between percentage area of infarction obtained with standard deviation method and autopsy specimens was in the range: -13.5% to +13.2%. With threshold method (thresholds from 30% to 90% of signal intensity), difference was -15% to +23%. Manual contouring underestimated infarcted area by 2% comparing to autopsy results. The best agreement between histopathology and semi-automated software was achieved for 4 standard deviations with standard deviation method: difference -0.45%, and for a percentage threshold of 70% (difference +0.67%) with threshold method. However, with standard deviation method, there was statistically significant difference between ROIs based on their location in viable myocardium: mean difference 1.7 +/- 4%, P < .0001. Conclusion: Semiautomated measurement of myocardial infarcted area on delayed enhanced magnetic resonance images performs well compared to autopsy. The threshold method, based on percentages of maximum signal intensity is preferable over standard deviation method, which is more susceptible to variability from location of ROIs within viable myocardium.

Published
2011

26. Late Cardiac Remodeling After Primary Percutaneous Coronary Intervention

Author

Springeling, Tirza, primary, Kirschbaum, Sharon W., additional, Rossi, Alexia, additional, Baks, Timo, additional, Karamermer, Yusuf, additional, Schulz, Carl, additional, Ouhlous, Mohammed, additional, Duncker, Dirk J., additional, Moelker, Adriaan, additional, Krestin, Gabriel P., additional, Serruys, Patrick W.J.C., additional, de Feyter, Pim, additional, and van Geuns, Robert-Jan M., additional

Published
2013
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30. Addition of the Long-Axis Information to Short-Axis Contours Reduces Interstudy Variability of Left-Ventricular Analysis in Cardiac Magnetic Resonance Studies

Author

Kirschbaum, Sharon W., primary, Baks, Timo, additional, Gronenschild, Ed H., additional, Aben, Jean-Paul, additional, Weustink, Annick C., additional, Wielopolski, Piotr A., additional, Krestin, Gabriel P., additional, de Feyter, Pim J., additional, and van Geuns, Robert-Jan M., additional

Published
2008
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31. Non-invasive visualization of coronary atherosclerosis: state-of-art

Author

Cademartiri, Filippo, primary, La Grutta, Ludovico, additional, Palumbo, Alessandro, additional, Malagutti, Patrizia, additional, Pugliese, Francesca, additional, Meijboom, W Bob, additional, Baks, Timo, additional, Mollet, Nico R, additional, Bruining, Nico, additional, Hamers, Ronald, additional, and de Feyter, Pim J, additional

Published
2007
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33. Hypertrophic Obstructive Cardiomyopathy

Author

Sianos, Georgios, primary, Papafaklis, Michail I., additional, Vourvouri, Eleni C., additional, Ligthart, Jurgen T., additional, Baks, Timo, additional, Ten Cate, Folkert J., additional, and Serruys, Patrick W., additional

Published
2006
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38. Effects of Primary Angioplasty for Acute Myocardial Infarction on Early and Late Infarct Size and Left Ventricular Wall Characteristics

Author

Baks, Timo, primary, van Geuns, Robert-Jan, additional, Biagini, Elena, additional, Wielopolski, Piotr, additional, Mollet, Nico R., additional, Cademartiri, Filippo, additional, van der Giessen, Willem J., additional, Krestin, Gabriel P., additional, Serruys, Patrick W., additional, Duncker, Dirk J., additional, and de Feyter, Pim J., additional

Published
2006
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44. Magnetic Resonance Imaging for Restenosis.

Author

Cannon, Christopher P., Armani, Annemarie M., Duckers, Henricus J., Nabel, Elizabeth G., Serruys, Patrick W., van Geuns, Robert Jan M., and Baks, Timo

Abstract

Magnetic resonance imaging (MRI) of the coronary arteries is a difficult subject. Owing to the motion of the heart during contraction and respiration artefact free imaging needs extremely fast techniques that MRI does not fully qualify yet. However, constant progress is made (1) and with electrocardiography triggering and respiratory motion correction techniques, submilliter resolution can be achieved with reasonable acquisition times (2). Only one study focussed on the use of magnetic resonance (MR) coronary angiography techniques for the detection of restenosis after coronary angioplasty (3). In this study, in which 118 patients after percutaneous transluminal coronary angioplasty were investigated, sensitivity for restenosis detection was 73% (11/15) and specificity was 49%. Overall accuracy was 53% for MRI, which was significantly (p = 0.014) lower compared with electron beam computed tomography. Unfortunately, MR coronary angiography of restenosis is currently hindered by the obligatory use of coronary artery stents to decrease the incidence of restenosis. Still MRI for the detection of restenosis is being performed using different alternative techniques and this subject will be reviewed in this chapter. [ABSTRACT FROM AUTHOR]

Published
2007
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45. Assessment of acute reperfused myocardial infarction with delayed enhancement 64-MDCT.

Author

Baks T, Cademartiri F, Moelker AD, van der Giessen WJ, Krestin GP, Duncker DJ, and de Feyter PJ

Subjects
Animals, Feasibility Studies, Myocardial Infarction etiology, Myocardial Reperfusion Injury complications, Myocardial Stunning etiology, Radiographic Image Enhancement instrumentation, Reproducibility of Results, Sensitivity and Specificity, Swine, Time Factors, Tomography, X-Ray Computed instrumentation, Myocardial Infarction diagnostic imaging, Myocardial Reperfusion Injury diagnostic imaging, Myocardial Stunning diagnostic imaging, Radiographic Image Enhancement methods, Tomography, X-Ray Computed methods
Abstract

Objective: The purpose of this study was to evaluate the utility of delayed enhancement 64-MDCT in the assessment of myocardial infarct size in a porcine model of acute reperfused myocardial infarction. CT can be used for noninvasive assessment of coronary artery stenosis, but to our knowledge, evaluation of myocardial viability in the subacute phase of acute myocardial infarction has not been validated. We performed delayed enhancement imaging on six domestic swine 5 days after reperfused acute myocardial infarction and assessed the relation between delayed enhancement patterns in vivo and the extent of viable and nonviable myocardium at postmortem histochemical analysis., Conclusion: Delayed enhancement imaging with 64-MDCT can be used for accurate assessment of the size of reperfused acute myocardial infarcts.

Published
2007
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46. Images in cardiovascular medicine. Hypertrophic obstructive cardiomyopathy: septal ablation with overlapping sirolimus-eluting and covered stents after failed alcoholization and concomitant coronary artery disease.

Author

Sianos G, Papafaklis MI, Vourvouri EC, Ligthart JT, Baks T, Ten Cate FJ, and Serruys PW

Subjects
Adult, Angioplasty, Balloon, Coronary, Combined Modality Therapy, Coronary Disease complications, Coronary Disease therapy, Drug Implants, Dyspnea etiology, Ethanol administration & dosage, Heart Septum pathology, Humans, Magnetic Resonance Imaging, Male, Mitral Valve Insufficiency complications, Physical Exertion, Recurrence, Sclerosing Solutions administration & dosage, Sirolimus administration & dosage, Sirolimus therapeutic use, Stents, Tomography, Spiral Computed, Ultrasonography, Cardiomyopathy, Hypertrophic diagnostic imaging, Coronary Disease diagnostic imaging, Ethanol therapeutic use, Heart Septum diagnostic imaging, Sclerosing Solutions therapeutic use
Published
2006
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47. Improving diagnostic accuracy of MDCT coronary angiography in patients with mild heart rhythm irregularities using ECG editing.

Author

Cademartiri F, Mollet NR, Runza G, Baks T, Midiri M, McFadden EP, Flohr TG, Ohnesorge B, de Feyter PJ, and Krestin GP

Subjects
Contrast Media, Coronary Angiography, Female, Humans, Iopamidol analogs & derivatives, Male, Middle Aged, Predictive Value of Tests, Prospective Studies, Sensitivity and Specificity, Atrial Fibrillation diagnostic imaging, Bradycardia diagnostic imaging, Cardiac Complexes, Premature diagnostic imaging, Electrocardiography, Tomography, X-Ray Computed methods
Abstract

Objective: The objective of our study was to compare diagnostic accuracy of MDCT coronary angiography in a population of patients with mild heart rhythm irregularities before and after editing the ECG., Subjects and Methods: Thirty-eight patients who underwent MDCT coronary angiography and conventional coronary angiography were enrolled in the study. The inclusion criterion was the presence of mild heart rhythm irregularities (i.e., premature beats; atrial fibrillation; mistriggering; or low heart rate, defined as 40 beats per minute or less) during the scan. All patients underwent MDCT with the following parameters: 16 detectors; collimation, 0.75 mm; gantry rotation time, 375 msec; 120 kV; and effective milliampere-second setting, 500-600. Images were reconstructed in two settings: before ECG editing and after ECG editing (i.e., arbitrary modification of temporal windows within the cardiac cycle at the site of mild heart rhythm irregularities). Data sets were scored for the presence of significant stenoses (> or = 50% lumen reduction) in coronary segments > or = 2 mm diameter. The results of the two groups were compared with a McNemar test, and a p value of less than 0.05 was considered significant., Results: The sensitivity, specificity, and negative and positive predictive values of MDCT coronary angiography for the detection of significant stenoses before and after ECG editing were 63% (41/65) and 92% (78/85); 97% (251/260) and 96% (305/317); 87% (62/71) and 87% (81/93); 91% (251/275) and 97% (305/313), respectively (p < 0.05). The proportion of nonassessable segments was reduced from 17% (70/416) before ECG editing to 2% (10/416) after., Conclusion: ECG editing significantly improves diagnostic accuracy in a selected population of patients with mild heart rate irregularities.

Published
2006
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