A system reduces artifacts introduced by patient or table motion during generation of a composite image visualizing contrast agent flow. A system for generation of a composite medical image of vessel structure, includes an imaging device for acquiring multiple sequential images of vessel structure of a portion of patient anatomy in the presence of a contrast agent. An imaging processor aligns individual images of the multiple sequential images with a single particular mask image containing background detail of the portion of patient anatomy in the absence of contrast agent. The imaging processor forms data representing multiple digitally subtracted images by subtracting data representing the single particular mask image from aligned individual images of the multiple sequential images. The imaging processor associates different individual images of the multiple digitally subtracted images with different corresponding visual attributes and combines data representing the digitally subtracted images to form a composite image. A reproduction device presents the composite image to a user.