A method for plaque characterization. The method comprises obtaining a first
set
of image data created in response to a first x-ray energy level and including a
plurality of pixel elements. Each of the first pixel elements corresponds to a
unique location in an object being scanned. The method further comprises obtaining
a second set of image data created in response to a second x-ray energy level and
including a plurality of second pixel elements. Each of the second pixel elements
corresponds to one of the first pixel elements and the second x-ray energy level
is higher than the first x-ray energy level. The method also comprises calculating
a third set of image data in response to the first set of image data and the second
set of image data. The calculating includes subtracting each second pixel element
from the corresponding first pixel element.
