Intravenous subtraction angiography (ISA)

Indirect arteriography of the abdominal aorta was performed in 171 patients by means of an intravenous bolus injection followed by conventional photographic image subtraction; the renal arteries were shown in 125 patients, the aortic arch and neck vessels in 20, peripheral vascular occlusions after percutaneous transluminal angioplasty in 17 and A-V shunts in dialysis patients in seven. The technique of injection, radiography and subtraction is described and the required dose compared with that for renal angiotomography. Provided the patient is adequately prepared, both renal arteries can be adequately demonstrated by ISA in 90% of patients. Using high-intensification screens, renal ISA requires less than half the dose necessary for angiotomography with a tomographic box a is suitable as a valuable screening method in conjunction with excretion urography. In the extremities, ISA produced adequate demonstration of stenoses, the vessel wall and collaterals. ISA of A-V shunts in haemodialysis patients is to be preferred to peripheral I-V xero-arteriography. (orig.)