Digital subtraction angiography: intravenous and intra-arterial techniques.

As experience with digital subtraction angiography (DSA) increases, both its advantages and disadvantages have become more evident. Although the intravenous approach (IV-DSA) is safer and less expensive than conventional arteriography, images are frequently suboptimal. Good-quality IV-DSAs quite accurately detect hemodynamically significant lesions (sensitivity 92% and specificity 92%) but may overlook minor stenoses and wall irregularities (negative predictive value 69%). When fine detail is not required, IV-DSA may serve as the definitive radiographic examination. The intra-arterial approach (IA-DSA), which provides better images, uses less contrast medium, decreases the need for selective catheterization, and permits visualization of vessels in areas of sluggish flow, is being used more extensively. Careful consideration of the complementary roles of DSA, conventional arteriography, and noninvasive testing is necessary to provide accurate diagnostic information at the least hazard and expense to the patient.