Accuracy of three-dimensional ultrasonography in volume estimation of cervical carcinoma

Objective. To evaluate the accuracy of a three-dimensional (3D) ultrasound system in volume estimation of cervical carcinoma. Study design. Transvaginal 3D and two-dimensional (2D) scans on cervical carcinoma volumes were performed 1 day before surgery. The volume of cervical carcinoma measured from each surgical specimen was compared with the corresponding volume of the cervical tumor measured by a 3D ultrasound and with the conventional 2D ultrasound volume measurement calculated using the formula π/6 X(R₁ X R₂ X R₃), where R₁, R₂, and R₃ were the maximal transverse, anteroposterior, and longitudinal length of tumor, respectively. Limits of agreement and 95% confidence intervals were calculated and systemic bias between the methods was analyzed. The Klotz test was also used to assess the statistical significance of the degree of dispersion. Results. A total of 61 cases, 55 with exophytic tumors and 6 with endocervical tumors, were examined in this study. The limits of agreement between the volume measured from specimen and tumor volume determined by ultrasound were +6.68 to -6.10 mL for 3D measurements and +12.46 to -10.98 mL for 2D measurements. The Klotz test showed the discrepancy in the degree of dispersion between 3D and 2D ultrasound measurements was statistically significant (P = 0.01). Conclusion. The true volume of cervical carcinoma is measured more accurately by a 3D ultrasound system than 2D ultrasound.