Digital angiography: current status.

Digital angiography depends upon computer recording and manipulation of the radiographic image rather than the use of film. We use a small focal spot x-ray tube, a cesium iodide image intensifier and the image is recorded on a 512 X 512 matrix at 1.2 frames per second. Subtraction angiograms have been obtained in 250 patients and 86% of the results were graded as either good or excellent in head and neck examinations. There is however a small proportion of patients in whom results are unsatisfactory and in whom this fact can be attributed most often to cardiac failure. The advantages of digital intravenous and intra-arterial subtraction angiography have been evaluated and amount to improved patient safety, high system contrast and favourable cost effectiveness; these outweigh the limitations of the restricted field of view and the relatively low resolution of the image in comparison with conventional arteriography.