A system and method for dual energy CT spectral imaging that provides for accurate blood vessel stenosis visualization and quantification is disclosed. The CT system (10) includes an x-ray source (14) configured to project x-rays toward a region-of-interest of a patient that includes a blood vessel in a stenosed condition and having a plaque material therein. The CT system (10) also includes an x-ray detector (18) to receive x-rays (16) emitted by the x-ray source (14) and attenuated by the region-of-interest, a data acquisition system (DAS) (32) operably connected to the x-ray detector (18), and a computer (36) programmed to obtain a first set of CT image data for the region-of-interest at a first chromatic energy level, obtain a second set of CT image data for the region-of-interest at a second chromatic energy level that is higher than the first chromatic energy level, and identify plaque material in the region-of-interest by analyzing the second set of CT image data.
