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Biomedical subjects

W Ameling

Publications and source records attributed to W Ameling.

34 records · Page 2Linked to original sources
PubMed1977

[Detailed analysis of systolic and diastolic parameters in aortic valve disease (author's transl)].

The on-line computer-system for the analysis of cathlab data developed by us allows the immediate evaluation of the conventional pressure- and valve-opening as well as a new hemodynamic parameters. In addition the volume-analysis is performed by the videometry-program. In simultaneous pressure-volume-registrations the complementary calculation of important energetic items is possible. This expanded analysis by the aid of the computer-system enables a detailed pre- and postoperative study of great clinical-practical and scientific importance.

Aortic Valve↗
PubMed1976

[Data processing system for laboratory and hemodynamic heart catheterization measurements].

In cooperation with the Department of Electronic Data Processing Systems we have developed a data processing unit for the analysis of hemodynamic data at the Department of Internal Medicine I. The aim was to design a computer-system for the daily routine in heart-catheterizations as well as for the solution of scientific problems during hemodynamic studies. In the on-line-mode besides the ECG up to four pressures can be analysed simultaneously. Analog and digital tapes can also be processed off-line on demand. The concept of the whole system and the individual steps of computer-handling are adjusted to the problems of data-analysis in praxis from the viewpoint of the examining cardiologist. Since the system is interactive after each measurement and each given command the computer-results are displayed on the video-scope. Because of the modular structure of the program new medical criteria can easily be implemented at any time. Since the computer-system is not effectively used with only one cath-lab other units possibly of different hard-ware configuration can be connected simultaneously to the computer. Each cath-lab shares 16 K out of the total 32 K core-memory. The results are displayed graphically and alpha-numerically on video-scope, x-y-plotter and line printer. The sampling-rate for fluid-filled catheters is 200 Hz and for catheter-tip-manometers 400 Hz. Smothing and differentiation-procedures are adapted to the respective catheter-material. The computer-program calibrates the different pressure amplifiers automatically. After defining the catheter-position the pressure-signals are sampled for 10 s and immediately afterwards analyzed by the computer. The ECG and the corresponding pressure-curves are displayed on the video-scope. The automatically selected representative beat as well as each of the identified and numerated other beats of the sampling-phase can be displayed selectively together with its numerical results. The computer marks the positions within the pressure-curves, where the individual measurements were taken. Besides the systolic and diastolic pressures in valvular stenosis the maximal and mean systolic or diastolic gradients, ejection- or filling-period, valve-flow and valve-area are calculated autonomously. The calculation of cardiac-output, different volume-indices and stroke-work-index are based on Fick-method, thermo- or indicator-dilution technique. The contractility-parameters max dp/dt, t-max dp/dt, max dp/dt/DP, max dp/dt/P, VPM, V40, min dp/dt and the stiffness are computed for the left and on demand also for the right ventricle. Data of the patient and the operating-team, catheter-technique, complications and free comments are transmitted to the computer via terminal together with the actual time. The computer-system was drafted for permanent use. Therefore possible technical defects have been anticipated in the design of hard- and soft-ware. In cases of failure suitable steps allow the immediate restart of the system without loosing information...

Angiocardiography↗
PubMedDate not supplied

[Initial studies of 3-dimensional imaging using ultrasound].

In the study reported here three-dimensional sonographic imaging of organs was achieved for the first time. To make this possible it was first necessary to ensure, by appropriate guidance of the probe, that the sequence of sonographic sections was coordinated in their spatial arrangement. This was accomplished by constructing a probe guide with which parallel sonographic sections could be demonstrated. The distance between these sections was known, so that with the aid of suitable computer programs three-dimensional reconstruction of a kidney examined in a water bath was possible. Since, however, due to the uneven surface of the body, it will hardly be possible to obtain parallel sonographic sections of an organ, a new solution had to be found to ensure the necessary coordinated sequence of sections. The solution lay in rotating the probe. A further device was constructed in which the probe could be rotated farther, by known angles, from section to section. The pivotal point was at the center of the probe tip. The computer knew the angular distance between these sections and reconstruction to a three-dimensional image was therefore possible. Prior the three-dimensional reconstruction the ultrasonographic sections had to be contoured, since only the surface of the organ was available for three-dimensional image construction. Three-dimensional imaging of an organ can be achieved on the one hand by binary representation and on the other with a continuous organ surface. The advantage of binary representation is that the original sonographic data are incorporated in the image-producing process without any computer manipulation; with a continuous surface the distance between the individual sections has to be interpolated.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Simulation↗