Comparison Of Accuracy Of Prostate Model Volume Measurement Between 2 Dimensional And 3 Dimensional Ultrasonography.

Purpose: To compare accuracy of prostate model volume measurement between 2 dimensional (2D) and 3 dimensional ultrasonography (3D). Materials and Methods: Sixty prostate models were made using devil’s tongue jelly and shaped by cutting the surface. To compare the accuracy of prostate model volume measurement according to the size and shape of the prostate model, 60 models were divided into four groups according to shape (ellipsoid vs. ellipsoid–intravesical prostate protrusion, IPP) and size (20-50ml vs. 50-80ml). In vitro measurement of prostate models using 2D-HWL, 3D Axial mode, and 3D Sagittal mode was performed and compared. Statistical analysis including simple regression analysis, Bland-Altman plot, and paired samples t-test were performed.Results: The percentage of error in the measurement of ellipsoid prostate models (20 – 80ml) was 4.50% ± 2.33 (3D Sagittal mode), 4.85% ± 1.66 (3D Axial mode), 7.09% ± 2.60 (2D HWL) and there was no statistically different accuracy comparing to true prostate model volume among three measurement methods. Pierson’s correlation coefficient revealed higher positive correlation between true volume and measured volume; 0.977 (3D Sagittal mode), 0.976 (3D Axial mode), 0.964 (2D HWL) in the ellipsoid prostate models measurement and 0.989 (3D Sagittal mode), 0.979 (3D Axial mode), 0.941 (2D HWL) in the ellipsoid-IPP model measurement. However, the percentage of error in the measurement of ellipsoid-IPP prostate models (20 – 80ml) was 4.87% ± 2.74 (3D Sagittal mode), 7.04% ± 3.36 (3D Axial mode), 23.56% ± 13.63 (2D HWL), and 2D HWL showed significantly different volume measurement comparing to true volume (p< 0.001). In addition, there was statistically significant difference between 3D Axial mode measurement and true volume (p=0.047) in the measurement of ellipsoid-IPP prostate models (50 – 80ml). Bland-Altman plot showed higher percentage of mean difference between 2D HWL and true volume in the measurement of ellipsoid-IPP prostate models (20 – 80ml). Conclusion: In measuring prostate model volume, the 3D Sagittal mode is better than 3D Axial mode or 2D HWL measurement, especially irregular larger and IPP prostate models.