Intravenous arteriography using digital subtraction techniques.

The application of digital computers to electronic x-ray imaging devices has rejuvenated interest in the field of intravenous arteriography. By utilizing computer image subtraction techniques, digital roentgenographic systems based on fluoroscopy or computed tomography (scanned projection radiography) provide significantly improved vascular imaging compared with conventional film subtraction methods. Digital subtraction angiography schemes isolate contrast media in the vessel by detecting differences in images obtained before and after the injection of contrast medium or changes in the relative attenuation of contrast media at different x-ray energies. Present applications include carotid and peripheral arteriography, thoracic and abdominal aortography, pulmonary arteriography, and ventriculography. Future applications may include intracerebral and coronary arteriography. These systems should provide low-risk outpatient screening arteriography.