[Development of a new digital angiography system--improvement of rotational angiography and three dimensional image display]

Abstract

The prototype of a rotational digital angiography system, has been improved to expand its range of application. The new system features an improved hardware configuration and new digital processing device. The system, called "computerized dynamic stereoradiography", is based on rapid transverse rotation of the X-ray apparatus, serial circumferential radiography and binocular stereographic imaging. The new digital processing device was included in the apparatus to provide rotational digital angiography. In use, mask exposures are first taken and all data are collected on a real-time basis into frame memories. Immediately afterwards, the X-ray apparatus is returned to the starting point and and live images are obtained. Subtraction images of all frames can be produced by a keyboard operation that requires less than 10 seconds. Three-dimensional images are rendered by two display systems with a 5 degree angle of difference. These images move at the same speed of rotation of two cathode ray tubes with 1,024 lines per screen, so that optical 3-D images can be observed. Digital angiography without subtraction is also available in the new system in both rotational and sequential modes. This is particularly useful when examining emergency patients and those who cannot hold their breath during X-ray exposure. This paper presents the principle and theory of the new system, and discusses its potential for overcoming the problems presented by current angiographic procedures in clinical practice.