OBJECTIVE. This purpose of this study was to evaluate the accuracy and reproducibility of a voxel analysis technique for measuring noncalcified plaque in the coronary arteries. MATERIALS AND METHODS. Polyethylene phantoms representing noncalcified plaque were scanned in both MDCT and micro-CT scanners and inter- and intrareader variability of volume calculation was performed. RESULTS. Volume measurements by both MDCT and micro-CT were comparable to the true volume as measured by micrometry (textless 3%, p = 0.05). CONCLUSION. There appears to be no significant difference (textless 3%) between MDCT and micro-CT measurements. textcopyright American Roentgen Ray Society.