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PubMed1984

[Digital subtraction angiography with dynamic color function images].

The authors present for the first time the principles and initial results of a laboratory pilot plant with which parametric colour images can be produced in real time. These images are digital function images of the type originally made widely known by Höhne et al. The colour function images can be produced during conventional digital subtraction angiography (DSA) practically as a sideline, that is to say, with a minimum of time and effort, as a parallel product. Despite the fact that the course of the functional processes can be visualised dynamically, the only feature required is the storage capacity of a single digital TV screen image. Of course, the colour function image is not a substitute for exact quantitative evaluations. However, it does furnish a rapid survey of haemodynamic processes for a multitude of patients in routine diagnosis.

Analog-Digital Conversion↗
PubMed1984

[Advances in diagnosis and their significance for radiological practice].

Many changes have taken place in x-ray diagnosis from the early introductory days of tomography and the introduction and development of the image intensifier. Ultrasound marked a big step forward. There are now about 12 000 ultrasound units in the FRG. In general practice, ultrasound is mainly used for screening examinations of the abdominal organs, whereas in hospitals special examinations are of great importance, such as neonatal skull, thyroid gland, mammary gland, scrotal sonography, and the valuation of blunt traumas. In nuclear medicine, an important advance was the application of spect in the diagnosis and localisation of disturbances of regional myocardial perfusion in coronary heart disease. In the last years CT has revolutionised radiology. In the FRG, the number of CT units, and all kinds of CT investigations in hospitals and in general practice, have been increasing rapidly. In 1983, there were 361 CT scanners in the FRG. The interdisciplinary character of radiology emerges especially in those areas which are known as interventional radiology. The most important methods are percutaneous transluminal angioplasty, percutaneous transhepatic cholangiography, puncture and drainage of abscesses, extraction of intraluminal foreign bodies, as well as therapeutical occlusion of vessels. Digital subtraction angiography is a new imaging method which is now available at all major departments in Western Germany. The method is well established by transvenous contrast medium injection for examination of the carotids, the renal arteries, the aorta, and the larger vessels of the extremities. Another new imaging method, magnetic resonance, has produced excitement in medical imaging.(ABSTRACT TRUNCATED AT 250 WORDS)

Analog-Digital Conversion↗
PubMed1984

[Arterial digital subtraction angiography for visualizing hemodialysis shunts].

Intraarterial application of contrast medium in digital video subtraction angiography was used to visualize chronic haemodialysis arteriovenous shunts. Patient compliance could be enhanced by the use of small volumes of non ionic contrast medium (3 ml/inj.), and the use off thin needles. The diagnostic reliability was excellent for all 25 examinations.

Adult↗
PubMed1978

A method for continuous electrocardiodynamic monitoring.

A new method is presented for the monitoring of cardiac time intervals, e.g. in clinical and industrial work investigation. The methods yields 'on-line' the electrocardiodynamic time profile during rest as well as effort, and has applications in health care, sports and occupational medicine. By means of analog processing of an electrocardiographic signal, ear densitogram and beat-by-beat display of the measured cardiac time intervals as amplitude-modulated pulses, an 'electrocardiodynamic time profile' is obtained. In order to estimate the accuracy and the limitations of the method, a comparison with computerized methods was performed. In an ergonomic experiment carried out by a Romanian-Swedish research team, analog and digital methods for the detection of cardiac time intervals showed good agreement.

Adolescent↗
PubMed1979

Apperceptive signals demonstrating the dynamic disturbance of myocardial ischemia.

Analog pressure signals (catheter-tip manometers) from the left atrium, left ventricle, and aorta and a flow signal from the arota were obtained in 25, open-chest, anesthetized dogs in which 115 episodes of ischemia were produced in an area of the left ventricle subtended by the distal left anterior descending coronary artery and its last major diagonal branch. The left ventricular pressure and its first derivative (dP/dt) were displayed as an X-Y loop. The character of this loop went through a unique series of dynamic changes in 110 of the 115 ischemic episodes, indicating that this is a useful tool for monitoring myocardial ischemia. Spectrum pairs of the above signals were analyzed with digital computational transfer functions in 14 ischemic episodes of three experiments and preliminary assessment reveals unique pole and zero changes in many pairs during each episode which also may prove to be a useful indicator of the hemodynamic disturbance incurred during myocardial ischemia.

Analog-Digital Conversion↗
PubMed1976

International standard (C.C.I.T.T.) for transmitting biomedical analogue and digital data on the public telephone network.

Analogue transmission of biomedical signals over the public telephone network has advantages from the economic point of view over digitalized transmission. This paper deals with the special problems encountered with the transmission of biomedical signals. Furthermore, the new international transmission standard C.C.I.T.T. recommendation V. 16 is introduced. This standard has recently been adopted by the relevant study group and has been presented to the Plenary Assembly of the C.C.I.T.T. for final approval. This standard is compatible with the existing public telephone networks. The technical specifications of this standard allow the transmission of the three-channel ECG for diagnostic purposes, e.g., remote processing and computer-assisted evaluation, as well as the transmission of the one-channel ECG with acoustic coupling, e.g., in emergency cases and for pace maker monitoring.

Analog-Digital Conversion↗
PubMed1975

[A hybrid system for documentation of pathological findings (author's transl)].

Considerations on the theory of communication point to the importance of "redundant" data in medicine. These usually arise from texts such as catamneses, descriptions of findings etc., and escape digital data pooling and storage on organizational and financial grounds. Here, microfilm is available as an economical storage medium taking little room. Developments in recent years enable integration of automatic analog storage into digital information systems. The use of such a hybrid system in the field of pathology is described.

Analog-Digital Conversion↗
PubMedDate not supplied

A dual-processor computer for arrhythmia analysis.

In order to facilitate the analysis of 24-hour tape recordings of ECG for rhythm by the AZTEC technique, we have configured a dual-processor system. It samples the ECG signal from a tape playback unit at a rate of 7501.88 Hz, allowing analysis at 30 x real time. An approach to error recognition and containment for the program, which utilizes the sampling of events, is discussed. Steps are taken to reduce errors caused by human sampling of "high risk" regions of the record.

Analog-Digital Conversion↗
PubMed1976

Analog vs. digital photogrammetry for optic cup analysis.

This report compares the reproducibility of analog and digital photogrammetry for topographical analysis of the optic cup. Ten simultaneous stereophotographs of each of three optic discs were taken with the Zeiss fundus camera plus a twin-prism stereoseparator. Digital processing produced photogrammetric contours of the optic cup and estimates of its geometry. Optic cup contours from the same stereopairs were also drawn with an analog stereoplotter and were analyzed by manual planimetry. The reproducibility of digital photogrammetry and analysis for estimation of cup depth, cup width, cup cross sectional area, and cup volume was concluded to be generally superior to the reproducibility of analog photogrammetry and manual analysis.

Analog-Digital Conversion↗