15 Fakultätsübergreifend / Sonstige Einrichtung
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/16
Browse
32 results
Search Results
Item Open Access Die Ermittlung von Steuerprofilen zur Insulinabgabe mit programmierbaren Insulininfusionssystemen(1981) Schulz, Gerhard; Beyer, Jürgen; Nagel, Joachim H.; Strack, Thomas; Krause, Ulrich; Hassinger, Wieland; Cordes, UweDer Insulinverbrauch und die Form der Insulinabgabeprofile bei intravenöser Insulintherapie mit nicht rückgekoppelten Infusionsgeräten wurde bisher nur rein empirisch ermittelt. Dabei war die Form der Insulinabgabeprofile nicht zuletzt auch von den technischen Möglichkeiten des Dosiergerätes abhängig. Unser Ziel war es, Grundsätze für die Blutzuckerführung mit Open-Loop-Systemen zu entwickeln. Die Insulinprofile sollten dem Blutzuckeranstieg und Abfall nach den Mahlzeiten möglichst gut angepaßt sein und individuell programmiert werden können, so daß der Patient zu den Mahlzeiten das entsprechende Programm abrufen kann.Item Open Access Quantification of aortic stenosis based on the morphology of Doppler ultrasound signals using image processing techniques(1994) Zahn, Thomas P.; Nagel, Joachim H.; Agatston, Arthur S.A method was developed to evaluate the morphologic structure of continuous wave Doppler ultrasound signals in order to quantify aortic valve stenosis in the human heart. The systolic peaks of the Doppler signal were assigned digital images and the stability of shape information was tested for patients with low stroke volume and aortal fibrillation. The results indicate that the shape of the signal peaks remains stable despite variations in amplitude and duration. The shape information was then used to quantify the severity of aortic stenosis by optimally matching Doppler peak images to selected templates representing typical diagnostic patterns. The developed software is capable of automatic extraction of shape information from Doppler ultrasound signals in order to support the clinical decision about valve functioning and replacement.Item Open Access Digital signal processing of the fetal heart sound(1982) Kartmann, Peter; Schlotter, Claus M.; Zhou, Li Gao; Nagel, Joachim H.; Schaldach, Max-Item Open Access Diagnosis and modelling of Alzheimer's disease through neural network analyses of PET studies(1990) Kippenhan, Jonathan Shane; Nagel, Joachim H.The back-propagation neural network algorithm was applied to the analysis of regional patterns in cerebral function, as demonstrated in positron emission tomography (PET). A trained network was able to successfully distinguish PET scans of normal subjects from PET scans of Alzheimer's Disease patients. It is concluded that the combination of PET and neural networks is a useful diagnostic tool for Alzheimer's Disease. A new paradigm for back-propagation learning is discussed which emphasizes its similarity to template matching. It is demonstrated that, under certain circumstances, the back-propagation network can be used as an estimation tool, as well as a classification tool, i.e., a trained neural network can indicate the criteria by which its classifications are performed.Item Open Access Beam/ray imaging(1988) Nagel, Joachim H.The diagnosis of disease is facilitated by imaging internal structures of anatomy and metabolic processes. The basic medical imaging techniques are radiographic (X-ray) imaging, nuclear medicine (gamma-ray) imaging, magnetic resonance imaging (MRI), ultrasound (US) imaging, and endoscopy. With the exception only of ultrasonic imaging, these techniques use electromagnetic waves as information carriers or measuring probes. According to the nature and wavelength of the radiation used and the properties of its interaction with tissue, including its ability to penetrate, specific diagnostic applications and imaging principles have been developed for each type of radiation.Item Open Access Elektronische Simulation der Reizausbreitung im Herzen(1980) Müller, Heinz; Nagel, Joachim H.; Schaldach, MaxDas beschriebene Gerät erweist sich als wertvolles Hilfsmittel zur Veranschaulichung der Reizausbreitung im Herzen im Zusammenhang mit den meßbaren Potentialen. Durch Anschluß eines Schrittmachers kann dessen Verhalten bei verschiedenen Rhythmusstörungen des Herzens sowie bei Störfällen beobachtet werden.Item Open Access Fast multimodality image matching(1988) Apicella, Anthony; Nagel, Joachim H.; Duara, RanjanThe diagnostic potential of medical images obtained at different times or from complimentary imaging modalities may be augmented by objective, accurate matching of the different data sets. Correlation analysis offers a powerful technique for the computation of translation, rotation, and scaling differences between image data sets, especially in the case of complimentary images containing similar but not exact information. So far, this technique suffers from the drawback of high computational expense. We have reformulated this approach, yielding a fast, computationally much less expensive algorithm. Reduction of computation time is about seventy five percent.Item Open Access New diagnostic and technical aspects of fetal phonocardiography(1986) Nagel, Joachim H.A new generation of instruments designed to record the fetal phonocardiogram is discussed, as are new methods of time-domain and frequency-domain processing of the fetal phonocardiogram. Using these techniques, detailed information can be obtained about both fetal and maternal cardiovascular conditions.Item Open Access Decomposition of heart rate variability by adaptive filtering for estimation of cardiac vagal tone(1991) Han, Kedu; Nagel, Joachim H.; Hurwitz, Barry E.; Schneiderman, NeilHeart rate fluctuations resulting from respiration and other influences upon the cardiovascular system are encoded into the patterns of heart rate variability (HRV). The fluctuations due to respiration are called respiratory sinus arrhythmia (RSA). Since RSA is primarily mediated through the autonomic nervous system (ANS), it is of interest to separate RSA from other influences to assess the underlying ANS function. On the other hand, the RSA may obscure heart rate responses to external manipulations in psychophysiological tests. A method of partitioning the HRV signal which can provide quantitative estimate of RSA as well as true heart rate responses without respiratory disturbances for psychophysiological studies is developed. The analysis of HRV signal is performed using an adaptive filtering system. With the simultaneously recorded respiration signal as a reference input, the HRV signal can be separated into two components, RSA and fluctuation due to other influences. After the separation, the variance of RSA, an estimate of cardiac vagal tone (ECVT), is readily obtained. The performance of the system was evaluated using artificial test signals as well as real HR V data. As a time domain approach, the method is simple, fast and robust.Item Open Access A fast correlation technique for multimodality image matching(1988) Apicella, Anthony; Nagel, Joachim H.-