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Biomedical engineering support. Quarterly progress report, June 15, 1971-- September 15, 1971

Description: A daily power profile for the artificial heart has been determined from the literature and equipment and instrumentation has been assembled for measuring the efficienciea and power losses in the Kwan-Geff antificial heart. (auth)
Date: October 11, 1971
Creator: Kolff, W.J. & Donovan, F.M. Jr.
Partner: UNT Libraries Government Documents Department

Biomedical engineering support. Quarterly progress report, September 15, 1971--December 15, 1971

Description: The power input to the air drive line, input to the air chamber, input to the pumping diaphragm and output from the Kwan-Gett artificial heart has been measured at different atrial pressures with a constant frequency of 120 beats per minute and constant mean arterial pressure of 100 mm Hg. These measurements were made in vitro. The various efficiencies, cardiac outputs and pressures corresponding to the power measurements were also determined. (auth)
Date: December 16, 1971
Creator: Kolff, W.J. & Donovan, F.M. Jr.
Partner: UNT Libraries Government Documents Department

Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report

Description: This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.
Date: January 1, 1999
Creator: Borovetz, H.S.; Shaffer, F.; Schaub, R.; Lund, L. & Woodard, J.
Partner: UNT Libraries Government Documents Department


Description: The Bayes Inference Engine (BIE) has been used to perform a 4D reconstruction of a first-pass radiotracer bolus distribution inside a CardioWest Total Artificial Heart, imaged with the University of Arizona's FastSPECT system. The BIE estimates parameter values that define the 3D model of the radiotracer distribution at each of 41 times spanning about two seconds. The 3D models have two components: a closed surface, composed of hi-quadratic Bezier triangular surface patches, that defines the interface between the part of the blood pool that contains radiotracer and the part that contains no radiotracer, and smooth voxel-to-voxel variations in intensity within the closed surface. Ideally, the surface estimates the ventricular wall location where the bolus is infused throughout the part of the blood pool contained by the right ventricle. The voxel-to-voxel variations are needed to model an inhomogeneously-mixed bolus. Maximum a posterior (MAP) estimates of the Bezier control points and voxel values are obtained for each time frame. We show new reconstructions using the Bezier surface models, and discuss estimates of ventricular volume as a function of time, ejection fraction, and wall motion. The computation time for our reconstruction process, which directly estimates complex 3D model parameters from the raw data, is performed in a time that is competitive with more traditional voxel-based methods (ML-EM, e.g.).
Date: January 2000
Creator: Cunningham, G. S. & Lehovich, A.
Partner: UNT Libraries Government Documents Department

Artificial heart development program. Volume II. System support. Phase III summary report. Period covered: July 1, 1973--September 30, 1977

Description: Appendix A covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detail procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested.
Date: January 1, 1977
Partner: UNT Libraries Government Documents Department

Artificial heart development program. Volume I. System development. Phase III summary report

Description: The report documents efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power systems portion is physically that portion of the implantable model between the Pu-238 heat sources and the blood pump ventricles. The work performed had two parallel themes. The first of these was the development of an integrated implantable model for bench and animal experiments plus design effort on a more advanced model. The second was research and development on components of the system done in conjunction with the development of the implantable model and to provide technology for incorporation into advanced models plus support to implantations, at the University of Utah, of the systems blood pumping elements when driven by electric motor. The efforts and results of implantable model development are covered, mainly, in the text of the report. The research and development efforts and results are reported, primarily, in the appendices (Vol. 2).
Date: January 1, 1977
Partner: UNT Libraries Government Documents Department

Classification of heart valve single leg separations from acoustic clinical measurements

Description: Our system classifies the condition (intact or single leg separated) of in vivo Bjork-Shiley Convexo-Concave (BSCC) heart valves by processing acoustic measurements of clinical heart valve opening sounds. We use spectral features as inputs to a two-stage classifier, which first classifies individual heart beats, then classifies valves. Performance is measured by probability of detection and probability of false alarm, and by confidence intervals on the probability of correct classification. The novelty of the work lies in the application of advanced techniques to real heart valve data, and extensions of published algorithms that enhance their applicability. We show that even when given a very small number of training samples, the classifier can achieve a probability of correct classification of 100%.
Date: May 1, 1994
Creator: Clark, G. A.; Bowman, B. C.; Boruta, N.; Thomas, G. H.; Jones, H. E. & Buhl, M. R.
Partner: UNT Libraries Government Documents Department

Available space for a totally implantable cardiac prosthesis. Annual progress report, April 1, 1973--March 31, 1974

Description: Methods were developed for generating an integrated, statistical model of the anatomical structures within the human thorax relevant to radioisotope powered artificial heart implantation. These methods involve measurement and analysis of anatomy in four areas: chest wall, pericardium, vascular connections, and great vessels. A model for the prediction of thorax outline from radiograms was finalized. These models were combined with 100 radiograms to arrive at a size distribution representing the adult male and female populations. (CH)
Date: April 1, 1974
Creator: Nose, Y.
Partner: UNT Libraries Government Documents Department