Evaluation of high resolution digital subtraction angiography in neuroradiology

A digital subtraction angiography (DSA) system has been modified for capabilities of a 1024 x 1024 matrix with 10 bit depth. Spatial resolution was increased with expansion of the matrix, but contrast resolution was not increased as determined by phantom experiments. Smaller focal spots and magnification factors were also important for improvement of spatial resolution. Clinical evaluation using carotid, vertebral, and cervical DSA with intra-arterial contrast injections demonstrated that there was slight improvement in the image quality, but the final diagnosis and management of patients were not changed with the use of high resolution DSA. Further improvements in image quality of DSA will be accomplished by improvements of image intensifiers and use of smaller focal spots.