Digital angiography.

The many available methods of digital subtraction angiography (DSA) are briefly reviewed. At present the most commonly used are temporal filtration techniques, which include conventional subtraction, integrated remasking , and various types of filtering. Their present use in intravenous, as well as intra-arterial, DSA is shown. The "moving mask" subtraction technique for cardiac and coronary studies is of particular interest. The current status of second-order subtraction techniques such as tomographic DSA and parametric digital imaging is presented. The latter method is particularly useful for demonstration of shunts. Finally, several examples of non-angiographic and future applications of digital radiography are presented.