Though intravenous digital subtraction angiography (IV DSA) has several advantages over conventional angiography in diagnosis and follow up of various vascular disease, it also has several undesirable problems such as large volume of the contrast medium and inferior image quality compared to conventional angiography. So recently intrarterial digital subtraction angiography (IA DSA) was introduced for better image quality using small amount of contrast medium. The authors had good clinical results IA DSA which was made in 20 patients with our own system, SRM-11 developed by cooperation of Departments of Radiology and Medical engineering, Seoul National University Hospital. Intraarterial digital substraction angiography was found to have several advantages over conventional angiography : (a) small amount of contrast medium, (b) reduced need for selective arterial catheterization. (c) lower film cost, (d) shortened examination time, (e) ability to obtain a "road map", and (f) easier detection of contrast medium. Also IA DSA has several advantages over IV DSA: (a) less dependency on cardiac output, (b) far less vessel overlapping, (c) reduction in patient motion through less painful procedure by reduced volume of contrast media and shorter imaging time.ging time.