Patent ID: 8655041

Claim:
A method for automatically detecting the presence of a contrast agent in an x-ray image, comprising: acquiring a preliminary x-ray image of a region of interest of a subject prior to administration of the contrast agent; estimating a background image based on the acquired preliminary x-ray image; administering the contrast agent into the subject; acquiring a main set of x-ray images including a plurality of image frames; subtracting the estimated background image from each image frame of the acquired main set of x-ray images to create a plurality of subtracted images corresponding to the plurality of image frames; determining a measure of image intensity for each of the subtracted images; selecting one or more of the subtracted images having a highest image intensity; fitting a predefined shape model to the selected one or more subtracted images; using the fitting of the predefined shape model to the one or more subtracted images to fit the shape model to each of the plurality of subtracted images; calculating a feature value for each image frame based on pixel intensities of each pixel fitted to the shape model for the corresponding subtracted image; and determining an image frame of peak contrast by selecting the image frame with the greatest feature value.