Subtraction techniques for digital cardiac imaging have been hampered by misregistration artifacts. The use of dual-energy imaging is being evaluated as a means for reducing these artifacts. Results reported previously indicate that the dual-energy technique may be useful for applications such as exercise ventriculography and general quantification tasks. The purpose of the current study is to investigate the use of dual-energy subtraction imaging for quantitative coronary arteriography. In vivo coronary vessel phantoms (0.2 to 7 mm2 in cross-sectional area) were used to study the potential advantages of tissue suppressed energy subtracted images over unsubtracted images for quantification of absolute vessel cross-sectional area when cardiac motion is present. Estimates of lumen cross-sectional area (N = 20) were determined using videodensitometric analysis of selected energy subtracted and unsubtracted images. Linear regression analysis of measured and actual cross-sectional area showed energy subtracted image data (slope = 1.06, intercept = 0.48 mm2, r = 0.99) to have improved accuracy (P less than .05) and precision (P less than .05) over unsubtracted image data (slope = 1.24, intercept = 1.07 mm2, r = 0.95).