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R Brennecke

Publications and source records attributed to R Brennecke.

At least 19 recordsLinked to original sources
PubMed2005

[The PhD program "Multimorbidity in Old Age and Selected Care Problems" Center for Human and Health Sciences of the Charité-Universitätsmedizin Berlin].

The PhD Program concerns the care of multimorbid geriatric patients. It takes a multidisciplinary approach in combining different perspectives on delivering care to the elderly. Students have completed courses of studies such as nursing, social education, sociology, psychology, or public health. Likewise, doctoral projects are overseen by members of various disciplines including medicine. These disciplines are represented in the Center for Human and Health Sciences of the Charité-Universitätsmedizin Berlin, where the PhD Program is located. The doctoral projects are grouped into three main topics--Care Problems and Interventions, Quality of Life and Self-Determination, and Care Structures and Quality.

Academic Medical Centers↗
PubMed2005

[Requirements of a future-oriented social medicine].

With the new national licensing regulations for physicians subsections of the social medicine became discrete subjects. The question arises, which contents the social medicine can have in the future, with consideration of important basic conditions. Such are the progress of medical knowledge, the representation of social medicine at medical faculties, changes of the medical supply, the transformation of jobs and the globalization. On a long-term basis effects of the demographic development, changes of the family structure and the financing of health and illness are important too. The social medicine should promptly make quality-assured contents available with consideration of the Internet. Such contents could be the comprehensive consultation, investigation and control of patient careers as well as the consultation and investigation from health problems in municipalities and in the society. In addition an inductive and practical oriented curriculum should be compiled, using the subject catalogue of the social medicine as well as a new basic textbook of social medicine.

Curriculum↗
PubMed2001

Comparison of image compression viability for lossy and lossless JPEG and Wavelet data reduction in coronary angiography.

BACKGROUND: Lossless or lossy compression of coronary angiogram data can reduce the enormous amounts of data generated by coronary angiographic imaging. The recent International Study of Angiographic Data Compression (ISAC) assessed the clinical viability of lossy Joint Photographic Expert Group (JPEG) compression but was unable to resolve two related questions: (A) the performance of lossless modes of compression in coronary angiography and (B) the performance of newer lossy wavelet algorithms. This present study seeks to supply some of this information. METHODS: The performance of several lossless image compression methods was measured in the same set of images as used in the ISAC study. For the assessment of the relative image quality of lossy JPEG and wavelet compression, the observers ranked the perceived image quality of computer-generated coronary angiograms compressed with wavelet compression relative to the same images with JPEG compression. This ranking allowed the matching of compression ratios for wavelet compression with the clinically viable compression ratios for the JPEG method as obtained in the ISAC study. RESULTS: The best lossless compression scheme (LOCO-I) offered a mean compression ratio (CR) of 3.80:1. The quality of images compressed with the lossy wavelet-based method at CR = 10:1 and 20:1 was comparable to JPEG compression at CR = 6:1 and 10:1, respectively. CONCLUSION: The study has shown that lossless compression can exceed the CR of 2:1 usually quoted. For lossy compression, the range of clinically viable compression ratios can probably be extended by 50 to 100% when applying wavelet compression algorithms as compared to JPEG compression. These results can motivate a larger clinical study.

Algorithms↗
PubMed2000

Ten-year outcome after coronary angioplasty in patients with single-vessel coronary artery disease and comparison with the results of the Coronary Artery Surgery Study (CASS).

The 10-year results of randomized trials comparing percutaneous transluminal coronary angioplasty (PTCA) in patients with single-vessel coronary artery disease (CAD) with coronary artery bypass grafting (CABG) and medical treatment are not available yet. The aim of this evaluation was to compare our 10-year follow-up results after PTCA in patients with single-vessel CAD with the 10-year follow-up results after CABG and medical treatment in the Coronary Artery Surgery Study (CASS) trial. We evaluated the clinical outcome of 509 patients with single-vessel CAD 10 years after coronary angioplasty. The data were compared with the results of 214 patients with single-vessel CAD after CABG or medical treatment from the CASS trial. End points were defined as death and myocardial infarction. Statistical evaluation was performed by life-table analysis and 2-sided Fisher's exact test. The rate of survival was 86% 10 years after PTCA compared with 85% after CABG and 82% after medical treatment in patients from the CASS trial (p = NS). Survival free from myocardial infarction was 77% after coronary angioplasty, 70% after CABG, and 72% after medical treatment (p = NS). Thus, in patients with single-vessel CAD, infarct-free survival 10 years after coronary angioplasty compared favorably with the results after bypass surgery or medical treatment from the CASS trial.

Adrenergic beta-Antagonists↗
PubMed2000

[A standardized documentation structure for data documentation in echocardiography. Work Team on Standards and LV Function of the Work Group on Cardiovascular Ultrasound of the German Society of Cardiology, Heart and Circulation Research].

Presently, there are no well-defined standards for documentation of echocardiographic studies. Nevertheless, standards are essential to provide comparability of data and to realize electronic communication, both essential for quality management in echocardiography. Therefore, the working group "Standards and LV function" of the German Society of Cardiology developed a consensus for documentation of echocardiographic studies. In the present paper this consensus is presented and illustrated by typical clinical examples. Additionally, a prototype of a user-oriented software based on this data set is presented. The complete data set for transesophageal and transthoracic echocardiography and the software prototype can be downloaded at http:@echo.ma.uni-heidelberg.de.

Aortic Valve Stenosis↗
PubMed2000

American College of Cardiology/European Society of Cardiology International Study of Angiographic Data Compression Phase III: measurement of image quality differences at varying levels of data compression.

OBJECTIVES: We sought to investigate up to which level of Joint Photographic Experts Group JPEG) data compression the perceived image quality and the detection of diagnostic features remain equivalent to the quality and detectability found in uncompressed coronary angiograms. BACKGROUND: Digital coronary angiograms represent an enormous amount of data and therefore require costly computerized communication and archiving systems. Earlier studies on the viability of medical image compression were not fully conclusive. METHODS: Twenty-one raters evaluated sets of 91 cine runs. Uncompressed and compressed versions of the images were presented side by side on one monitor, and image quality differences were assessed on a scale featuring six scores. In addition, the raters had to detect pre-defined clinical features. Compression ratios (CR) were 6:1, 10:1 and 16:1. Statistical evaluation was based on descriptive statistics and on the equivalence t-test. RESULTS: At the lowest CR (CR 6:1), there was already a small (15%) increase in assigning the aesthetic quality score indicating "quality difference is barely discernible-the images are equivalent." At CR 10:1 and CR 16:1, close to 10% and 55%, respectively, of the compressed images were rated to be "clearly degraded, but still adequate for clinical use" or worse. Concerning diagnostic features, at CR 10:1 and CR 16:1 the error rate was 9.6% and 13.1%, respectively, compared with 9% for the baseline error rate in uncompressed images. CONCLUSIONS: Compression at CR 6:1 provides equivalence with the original cine runs. If CR 16:1 were used, one would have to tolerate a significant increase in the diagnostic error rate over the baseline error rate. At CR 10:1, intermediate results were obtained.

Adult↗
PubMed2000

American College of Cardiology/ European Society of Cardiology international study of angiographic data compression phase III. Measurement Of image quality differences at varying levels of data compression.

OBJECTIVES: We sought to investigate up to which level of Joint Photographic Experts Group (JPEG) data compression the perceived image quality and the detection of diagnostic features remain equivalent to the quality and detectability found in uncompressed coronary angiograms. BACKGROUND: Digital coronary angiograms represent an enormous amount of data and therefore require costly computerized communication and archiving systems. Earlier studies on the viability of medical image compression were not fully conclusive. METHODS: Twenty-one raters evaluated sets of 91 cine runs. Uncompressed and compressed versions of the images were presented side by side on one monitor, and image quality differences were assessed on a scale featuring six scores. In addition, the raters had to detect pre-defined clinical features. Compression ratios (CR) were 6:1, 10:1 and 16:1. Statistical evaluation was based on descriptive statistics and on the equivalence t -test. Results At the lowest CR (CR 6:1), there was already a small (15%) increase in assigning the aesthetic quality score indicating "quality difference is barely discernible-the images are equivalent.' At CR 10:1 and CR 16:1, close to 10% and 55%, respectively, of the compressed images were rated to be "clearly degraded, but still adequate for clinical use' or worse. Concerning diagnostic features, at CR 10:1 and CR 16:1 the error rate was 9.6% and 13.1%, respectively, compared with 9% for the baseline error rate in uncompressed images. CONCLUSIONS: Compression at CR 6:1 provides equivalence with the original cine runs. If CR 16:1 were used, one would have to tolerate a significant increase in the diagnostic error rate over the baseline error rate. At CR 10:1, intermediate results were obtained.

Adult↗
PubMed1999

Predictors of adverse outcome 10 years after coronary angioplasty.

UNLABELLED: To determine which factors before percutaneous transluminal coronary angioplasty (PTCA) predict long-term outcome, we evaluated the clinical follow-up data from 535 patients 10 years after single-vessel PTCA. Events were defined as death, myocardial infarction, bypass surgery or repeat PTCA. During the follow-up period 79 patients (15%) died, 59 patients (11%) suffered a myocardial infarction, 107 patients (20%) had coronary artery bypass surgery and 141 patients (26%) underwent a redilatation. To determine the predictors of 10-year follow-up, 12 patient-related and 9 lesion parameters were analyzed by logistic regression analysis. Mortality was independently increased in patients with diabetes, with multi-vessel disease, after a previous myocardial infarction and in smokers. The presence of multi-vessel disease, symptoms of a higher angina class and younger age increased the risk for undergoing bypass surgery. In the statistical model with lesion parameters, the risk of bypass surgery was decreased if the stenosis was located in the distal segment of the coronary vessel and by a higher minimal luminal diameter before PTCA. CONCLUSION: Logistic regression analysis identified multi-vessel disease, diabetes, smoking and a previous myocardial infarction as independent clinical predictors of an adverse outcome 10 years after coronary angioplasty. Lesion parameters before PTCA seem to be less important with regard to the long-term outcome after PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1998

Impact of routine angiographic follow-up after angioplasty.

BACKGROUND: There is an ongoing controversy as to whether repeat coronary angiography should be routinely performed after successful percutaneous transluminal coronary angioplasty (PTCA). METHODS: We examined the 10-year outcome in 400 patients who had or had not undergone an angiographic control 6 months after successful PTCA and a subsequent event-free 6-month period. Our comparison was based on data gathered by questionnaire and telephone interview in 315 patients with (group A) and 85 patients without (group B) a routine 6-month angiographic control. Multivariate analysis (Cox model) was performed to identify predictors of adverse events. RESULTS: During the 10-year follow-up period, 22 (7%) of the 315 patients in group A died, compared with 16 (19%) patients in group B (P= .003). In groups A and B, respectively, acute myocardial infarction occurred in 28 (9%) and 10 (12%) patients (not significant [NS]); coronary artery bypass grafting (CABG) was performed in 42 (13%) and 14 (16%) patients (NS); repeat PTCA was performed in 89 (28%) and 11 (13%) patients (P= .012); and serious adverse events (death, myocardial infarction, CABG) occurred in 76 (24%) and 32 (38%) patients (P= .02). Absence of a 6-month angiographic follow-up was identified as an independent predictor of death associated with a 2.7 times higher mortality rate during the 10-year follow-up period. Previous myocardial infarction increased the risk of death 2.5 times. Any increase of residual diameter stenosis by 10% was combined with a 1.4 times higher mortality rate. The chance of bypass surgery was higher in patients with multivessel disease (2.9 times), in patients with unstable angina (2.1 times), and in case of an increase of residual diameter stenosis by 10% (1.3 times). No predictor for the risk of myocardial infarction was found. Angiographic follow-up increased the likelihood of PTCA 2.5 times. CONCLUSIONS: A routinely performed angiographic control 6 months after successful PTCA is associated with a significantly higher rate of repeat PTCA but, most important, is correlated with a significantly lower mortality rate during the 10-year follow-up period.

Adult↗
PubMed1998

In vitro examination of the coronary artery wall after balloon angioplasty using intracoronary ultrasound.

After autopsy 12 human coronary arteries were investigated by intracoronary ultrasound in order to measure the vessel wall dimensions and to detect damage on the vessel wall architecture after balloon angioplasty. Histology revealed artherosclerosis in 11/12 arteries. A total of 41 representative coronary segments were selected for further off-line ultrasound and histological analysis. Intracoronary ultrasound and histological measurements of the vessel wall thickness after balloon dilatation demonstrated a good correlation between the maximum thickness of the intima (histology 0.62 mm vs. intracoronary ultrasound 0.65 mm, r = 0.87) and the intima-media complex (0.80 mm vs. 0.83 mm, r = 0.87), in contrast to a weak one between the minimum thickness (r = 0.46 and r = 0.37). A total of 21 cases of damage occurred during angioplasty; intracoronary ultrasound detected 17. Further analysis showed that it imaged 10 of 11 cases of damage involving more than 30 degrees of the vessel circumference and 7 of 10 cases of damage involving less than 30 degrees of the vessel circumference. After balloon angioplasty of diseased coronary arteries, intracoronary ultrasound is therefore reliable in measuring the maximum wall thickness and in imaging damage involving more than 30 degrees of the vessel wall circumference.

Angioplasty, Balloon↗
PubMed1998

Impact of restenosis 10 years after coronary angioplasty.

AIMS: The aim of the study was to compare the 10-year follow-up results of patients with or without restenosis following single-vessel percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: A total of 313 patients with successful PTCA (> or = 20% reduction in luminal diameter narrowing without acute complications) and a control angiography 6 months after PTCA were included in the study. Events during the follow-up period were defined as death, myocardial infarction, bypass surgery, or repeat PTCA. Statistical evaluation was performed by the Fisher test, logistic regression, and life-table analysis. Restenosis (loss of > 50% of the initial gain and diameter stenosis of 50%) was found in 87 (28%) patients. During follow-up, 11 patients (5%) without restenosis (group A) and 11 (13%) patients with restenosis (group B) died (P < 0.05). In group A, 17 (8%) patients and in group B, 11 (13%) patients suffered myocardial infarction (ns); 17 group A (8%) patients and 25 (29%) group B patients had bypass surgery (P < 0.0001), and 34 (15%) group A patients and 55 (63%) group B patients underwent repeat PTCA (P < 0.0001). Logistic regression analysis identified restenosis as an independent risk factor that increases the risk of death 2.8-fold (P = 0.02), bypass surgery 5.6-fold (P < 0.0001), and repeat PTCA 10-fold (P < 0.0001). CONCLUSION: We conclude that patients with restenosis had a poorer long-term outcome than patients without restenosis. Although most patients with restenosis underwent repeat PTCA, the survival rate without any serious adverse events was only 59%, compared with 83% in patients without restenosis (P < 0.0001).

Adult↗
PubMed1998

[Berlin-Brandenburg-Saxony Rehabilitation Research Group].

The principal subject of the Rehabilitation Research Network of Berlin, Brandenburg and Saxony (BBS) is "the theoretical and practical bases of the organisation and economics of rehabilitation". What is involved is a nation-wide analysis of the rehabilitation system, i.e. obtaining empirical information on the question as to what organisational forms are currently used to carry out rehabilitation and what results are achieved. This empirical stocktaking also includes economic aspects as far as possible. This study is to serve as a basis for developing, testing and implementing steps to rationalise steering mechanisms in the rehabilitation system. The first aspect to be studied is "national steering problems in institutionalised forms of rehabilitation". The focus is on projects on information management and performance and quality management in rehabilitation sciences as well as on the actual work of a number of bodies paying for rehabilitation (Bundesversicherungsanstalt für Angestellte, Landesversicherungsanstalten) as well as rehabilitation facilities (clinics etc.). The two other focuses of the study will examine "rehabilitative adjustment to remedies and technical aids/prostheses" and problems facing "family members in the context of rehabilitation". In studying these two areas, we are particularly interested in examining the interaction between institutionalised aspect of rehabilitation and informal factors both inside and outside the system. The BBS approach is supported by close co-operation with the regional pension insurance institutes (BfA, LVAs) with regard to both the data model and steps being taken. The principal instrument of co-operation is the "Gesellschaft für Rehabilitationswissenschaften e.V." (Society for Rehabilitation Sciences). In Berlin the BBS co-operates with Free University, the Technical University and the Robert Koch Institute and in Saxony with the universities in Dresden and Leipzig. Responsibility for scientific questions in the BBS lies with the Institute for Rehabilitation Sciences of Berlin's Humboldt University.

Cost-Benefit Analysis↗