Digital subtraction angiography: present and future uses in cardiovascular diagnosis

Digital subtraction angiography (DSA) has been proved to be an effective means of visualizing the cardiovascular system following intravenous injection of contrast material. Excellent quality images have been obtained of the left ventricle, the thoracic aorta and its major branches, the carotid arteries, the abdominal aorta and its major branches, lower extremity vessels, and intracerebral vessels. Avoiding the risks and discomforts of direct arterial puncture and the need for hospitalization, DSA is safer and more economical than standard arteriography. It is, therefore, useful both as a screening tool and, in many patients, as a diagnostic tool for the evaluation of vascular disease. Left ventricular studies provide excellent qualitative and quantitative evaluation of left ventricular function. Arterial injections of contrast have provided excellent quality images of the vascular tree with low volume dilute contrast material. Lower extremity vessels not visualized by standard arteriography have been seen following intra-arterial contrast injections using DSA. Aortic root injections have been used to demonstrate coronary arteries and coronary artery bypass grafts. Although intravenous injections of contrast have shown coronary artery bypass graft patency with reasonable success, they have not proved useful at this point in defining the exact anatomy. Other video techniques following arterial injections of contrast have been used to calculate vessel flows. Although coronary artery images in animal studies following intravenous contrast injection are improving, they are still not of diagnostic quality. Digital subtraction angiography, therefore, has proved itself a useful adjunct to standard arteriographic techniques. Its future potential has not yet been defined.