1. A method for identifying an ideal plasma region of interest in a series of medical images, the method comprising: (a) receiving image data representing the series of medical images into a computing device; (b) receiving an identification of a plasma region; (c) automatically assigning a score to each voxel in the image data in accordance with suitability for inclusion in the ideal plasma region of interest; and (d) identifying the ideal plasma region of interest as including a plurality of voxels whose scores as assigned in step (c) are highest.