Intra-arterial DSA: early experience with a 1024² matrix

Summary

Twenty patients were studied with intraarterial digital subtraction angiography (IA DSA), utilizing a 1024² matrix memory. Acquisition of the images was through a prototype television camera incorporating a finely focused electron beam. In five cases, comparison between a 512×512 (512²) matrix acquisition and a 1024×1024 (1024²) matrix acquisition mode was made, with injections occurring in the same vessel in the same patient. The clinical material demonstrated no significant improvement in image quality at the 41/2 as well as the 6 inch image intensifier (II) modes. However, the 1024² matrix combined with the 9 inch II mode showed foci of disease and normal anatomy with detail not always seen on the 9 inch II when a 512² matrix was used. In no case, however, was the basic diagnosis missed with the 512² matrix. Spatial resolution, as measured from lead bar test pattern images, demonstrated that the 1024² matrix allows a 70% or greater improvement in spatial resolution over the 512² for the 41/2, 6 and 9 inch II modes. For a given mode the radiation dose was held constant for the two matrix sizes.