MASK CONSTRUCTION FOR CARDIAC SUBTRACTION

摘要

To provide an improved method for achieving DSA images where the effect of residual motions in cardiac DSA during the perfusion phase is reduced and in order to display subtracted images containing less motion artefacts, a method of performing digital subtraction angiography DSA in an imaging apparatus comprises the steps of generating a first image sequence of mask images (10) of a subject to be examined, generating at least one first contrast image (22) at a first phase (16) whereby in the first contrast image part of the subject has a different contrast than in said first image sequence, subtracting the mask images (10) from the at least one first contrast image (22) generating a first DSA image sequence (24), subtracting the DSA images of the first DSA image sequence (24) from the first contrast image (22) within the first phase (16) generating a sequence of extended mask images (32); generating a second contrast image (34) with the imaging system at a second phase (18), said second phase (18) being separated from the first phase (16) by a predetermined phase dividing time limit (20), subtracting the images of the sequence of the extended mask images (32) from the second contrast image (34) generating a second DSA image sequence (38), displaying the second DSA image sequence (38) on a display (28).