Generation of a subtraction mask for digital angiography based on the movement of the coronary

A synthetic mask technique for angiography of coronary arteries was experimentally studied, using conventional 35 mm film sequences of coronary arteries. The method makes use of the fact that because of the movement of the heart vessels different parts of the background will be hidden. The background is extracted from two or more neighbouring frames by computer assistance and afterwards used for a subtraction mask. The experiments showed that the synthetic masks are of a good accuracy, the background anatomy is markedly reduced and the contrast is increased.