3D versus 2D ultrasound: accuracy of volume measurement in human cadaver kidneys

RATIONALE AND OBJECTIVES: Comparison of the accuracy of 3D and 2D ultrasound in assessing the volume of human cadaver kidneys. MATERIALS AND METHODS: Before autopsy the volume of 22 kidneys was assessed from a 3D data set after manually tracing organ contours (3D volumetry) and by applying a 3D ellipsoid formula both on a 3D data set and 2D images. Measurements by water-displacement served as the gold standard. RESULTS: 3D volumetry showed a mean absolute deviation of 31 mL (18.5%) compared with the mean gold standard measurement (168 mL), yielding a concordance correlation (Lin's rho(c) ) of 0.71. Calculation based on the ellipsoid formula revealed a mean absolute deviation of 37 mL (22.0%) when applied on the 3D data set (rho(c) = 0.65) and of 42 mL (25.0%) when applied on 2D images (rho(c) = 0.61). CONCLUSIONS: 3D volumetry showed a satisfactory concordance correlation and is superior to volume calculation based on the ellipsoid formula either applied to a 3D data set or to conventional 2D images in assessing the volume of human cadaver kidneys.