A method of measuring vessel cross-sectional area includes imaging the cross-sectional area of the vessel, wherein the imaging includes: a central calibration region of interest (ROI) of the vessel to obtain a true Hounsfield unit (HU) an object ROI that includes a vessel area affected by a partial volume effect to obtain an object HU a ring ROI that is outside the object ROI to obtain a background HU and integrating the true HU, the object HU, and the background HU to calculate the cross-sectional area.
