6533b834fe1ef96bd129d4fa

RESEARCH PRODUCT

Digital Acquisition and Processing of Video Angiocardiograms

subject

description

Angiocardiographic diagnosis is still mainly based on the visual assessment of radiographic projection images recorded on photographic film. Considerable amounts of contrast material have to be selectively injected into the circulation in order to make the regions of diagnostic relevance visible in the superposition of the shadows of tissue and bone structures displayed in these transmission images. In addition, selective angiocardiography requires exact positioning of the catheter, a time-consuming procedure which is not without risk. The processing of the angiographie films obtained is difficult to maintain at a constant high quality level, and this introduces an disadvantageous delay between image recording and diagnostic evaluation. Electronic techniques of image recording and processing based on analog devices have not been able to replace film as the primary image storage medium in angiocardiography. However, the rapid development of digital microelectronic technology promises to offer the technical prerequisites for both high quality, flexible electronic image recording and reproducible image evaluation. The need for image processing, in addition to recording, results from two general requirements: 1. A wider demand for less invasive diagnostic procedures. The high sensitivity of the selective contrast material display offered by certain digital image processing techniques results in reduced patient load or makes possible an increased number of examinations at constant load, needed for follow-up studies, screening, or intervention angiocardiography. 2. The need for extraction of quantitative parameters characterizing functions such as regional blood flow or ejection fraction. The quantification of these parameters can help to support diagnostic decisions and to evaluate the success of a therapy. Analog videodensitometry and videometry can be applied to extract these data, but their application in a clinical environment has been limited by the need to interface the additional equipment necessary and its relatively complicated operation.