Is ovarian volume estimation reliable when compared with true volume?

Objective We aimed to evaluate the agreement of 2-dimensional (2D) and 3-dimensional (3D) ultrasonography (USG) with true ovarian volume (OV), as calculated precisely after oophorectomy. Study Design A total of 46 ovaries from 30 patients were prospectively enrolled. Preoperatively, all ovaries were assessed by 2D and 3D USG for volume estimation and results were compared with true OV that was calculated with Archimedes' principles following oophorectomy. Results The correlation coefficients of 2D and 3D USG with true OV were similar (0.65 vs 0.67, respectively). The mean bias (upper and lower limits of agreement) between 2D and true OV was 1.41 (–3.84 to 6.66) mL. The respective figure for 3D and true OV were 0.33 (–4.71 to 5.37) mL. While estimation by 2D USG brought 18% larger, 3D USG revealed 11% smaller values than the true OV. Conclusion Three-dimensional OV estimation might present improvement in means of lower mean bias than 2D USG.